+++ /dev/null
-/*P:100
- * This is the Launcher code, a simple program which lays out the "physical"
- * memory for the new Guest by mapping the kernel image and the virtual
- * devices, then opens /dev/lguest to tell the kernel about the Guest and
- * control it.
-:*/
-#define _LARGEFILE64_SOURCE
-#define _GNU_SOURCE
-#include <stdio.h>
-#include <string.h>
-#include <unistd.h>
-#include <err.h>
-#include <stdint.h>
-#include <stdlib.h>
-#include <elf.h>
-#include <sys/mman.h>
-#include <sys/param.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/wait.h>
-#include <sys/eventfd.h>
-#include <fcntl.h>
-#include <stdbool.h>
-#include <errno.h>
-#include <ctype.h>
-#include <sys/socket.h>
-#include <sys/ioctl.h>
-#include <sys/time.h>
-#include <time.h>
-#include <netinet/in.h>
-#include <net/if.h>
-#include <linux/sockios.h>
-#include <linux/if_tun.h>
-#include <sys/uio.h>
-#include <termios.h>
-#include <getopt.h>
-#include <assert.h>
-#include <sched.h>
-#include <limits.h>
-#include <stddef.h>
-#include <signal.h>
-#include <pwd.h>
-#include <grp.h>
-#include <sys/user.h>
-#include <linux/pci_regs.h>
-
-#ifndef VIRTIO_F_ANY_LAYOUT
-#define VIRTIO_F_ANY_LAYOUT 27
-#endif
-
-/*L:110
- * We can ignore the 43 include files we need for this program, but I do want
- * to draw attention to the use of kernel-style types.
- *
- * As Linus said, "C is a Spartan language, and so should your naming be." I
- * like these abbreviations, so we define them here. Note that u64 is always
- * unsigned long long, which works on all Linux systems: this means that we can
- * use %llu in printf for any u64.
- */
-typedef unsigned long long u64;
-typedef uint32_t u32;
-typedef uint16_t u16;
-typedef uint8_t u8;
-/*:*/
-
-#define VIRTIO_CONFIG_NO_LEGACY
-#define VIRTIO_PCI_NO_LEGACY
-#define VIRTIO_BLK_NO_LEGACY
-#define VIRTIO_NET_NO_LEGACY
-
-/* Use in-kernel ones, which defines VIRTIO_F_VERSION_1 */
-#include "../../include/uapi/linux/virtio_config.h"
-#include "../../include/uapi/linux/virtio_net.h"
-#include "../../include/uapi/linux/virtio_blk.h"
-#include "../../include/uapi/linux/virtio_console.h"
-#include "../../include/uapi/linux/virtio_rng.h"
-#include <linux/virtio_ring.h>
-#include "../../include/uapi/linux/virtio_pci.h"
-#include <asm/bootparam.h>
-#include "../../include/linux/lguest_launcher.h"
-
-#define BRIDGE_PFX "bridge:"
-#ifndef SIOCBRADDIF
-#define SIOCBRADDIF 0x89a2 /* add interface to bridge */
-#endif
-/* We can have up to 256 pages for devices. */
-#define DEVICE_PAGES 256
-/* This will occupy 3 pages: it must be a power of 2. */
-#define VIRTQUEUE_NUM 256
-
-/*L:120
- * verbose is both a global flag and a macro. The C preprocessor allows
- * this, and although I wouldn't recommend it, it works quite nicely here.
- */
-static bool verbose;
-#define verbose(args...) \
- do { if (verbose) printf(args); } while(0)
-/*:*/
-
-/* The pointer to the start of guest memory. */
-static void *guest_base;
-/* The maximum guest physical address allowed, and maximum possible. */
-static unsigned long guest_limit, guest_max, guest_mmio;
-/* The /dev/lguest file descriptor. */
-static int lguest_fd;
-
-/* a per-cpu variable indicating whose vcpu is currently running */
-static unsigned int __thread cpu_id;
-
-/* 5 bit device number in the PCI_CONFIG_ADDR => 32 only */
-#define MAX_PCI_DEVICES 32
-
-/* This is our list of devices. */
-struct device_list {
- /* Counter to assign interrupt numbers. */
- unsigned int next_irq;
-
- /* Counter to print out convenient device numbers. */
- unsigned int device_num;
-
- /* PCI devices. */
- struct device *pci[MAX_PCI_DEVICES];
-};
-
-/* The list of Guest devices, based on command line arguments. */
-static struct device_list devices;
-
-/*
- * Just like struct virtio_pci_cfg_cap in uapi/linux/virtio_pci.h,
- * but uses a u32 explicitly for the data.
- */
-struct virtio_pci_cfg_cap_u32 {
- struct virtio_pci_cap cap;
- u32 pci_cfg_data; /* Data for BAR access. */
-};
-
-struct virtio_pci_mmio {
- struct virtio_pci_common_cfg cfg;
- u16 notify;
- u8 isr;
- u8 padding;
- /* Device-specific configuration follows this. */
-};
-
-/* This is the layout (little-endian) of the PCI config space. */
-struct pci_config {
- u16 vendor_id, device_id;
- u16 command, status;
- u8 revid, prog_if, subclass, class;
- u8 cacheline_size, lat_timer, header_type, bist;
- u32 bar[6];
- u32 cardbus_cis_ptr;
- u16 subsystem_vendor_id, subsystem_device_id;
- u32 expansion_rom_addr;
- u8 capabilities, reserved1[3];
- u32 reserved2;
- u8 irq_line, irq_pin, min_grant, max_latency;
-
- /* Now, this is the linked capability list. */
- struct virtio_pci_cap common;
- struct virtio_pci_notify_cap notify;
- struct virtio_pci_cap isr;
- struct virtio_pci_cap device;
- struct virtio_pci_cfg_cap_u32 cfg_access;
-};
-
-/* The device structure describes a single device. */
-struct device {
- /* The name of this device, for --verbose. */
- const char *name;
-
- /* Any queues attached to this device */
- struct virtqueue *vq;
-
- /* Is it operational */
- bool running;
-
- /* Has it written FEATURES_OK but not re-checked it? */
- bool wrote_features_ok;
-
- /* PCI configuration */
- union {
- struct pci_config config;
- u32 config_words[sizeof(struct pci_config) / sizeof(u32)];
- };
-
- /* Features we offer, and those accepted. */
- u64 features, features_accepted;
-
- /* Device-specific config hangs off the end of this. */
- struct virtio_pci_mmio *mmio;
-
- /* PCI MMIO resources (all in BAR0) */
- size_t mmio_size;
- u32 mmio_addr;
-
- /* Device-specific data. */
- void *priv;
-};
-
-/* The virtqueue structure describes a queue attached to a device. */
-struct virtqueue {
- struct virtqueue *next;
-
- /* Which device owns me. */
- struct device *dev;
-
- /* Name for printing errors. */
- const char *name;
-
- /* The actual ring of buffers. */
- struct vring vring;
-
- /* The information about this virtqueue (we only use queue_size on) */
- struct virtio_pci_common_cfg pci_config;
-
- /* Last available index we saw. */
- u16 last_avail_idx;
-
- /* How many are used since we sent last irq? */
- unsigned int pending_used;
-
- /* Eventfd where Guest notifications arrive. */
- int eventfd;
-
- /* Function for the thread which is servicing this virtqueue. */
- void (*service)(struct virtqueue *vq);
- pid_t thread;
-};
-
-/* Remember the arguments to the program so we can "reboot" */
-static char **main_args;
-
-/* The original tty settings to restore on exit. */
-static struct termios orig_term;
-
-/*
- * We have to be careful with barriers: our devices are all run in separate
- * threads and so we need to make sure that changes visible to the Guest happen
- * in precise order.
- */
-#define wmb() __asm__ __volatile__("" : : : "memory")
-#define rmb() __asm__ __volatile__("lock; addl $0,0(%%esp)" : : : "memory")
-#define mb() __asm__ __volatile__("lock; addl $0,0(%%esp)" : : : "memory")
-
-/* Wrapper for the last available index. Makes it easier to change. */
-#define lg_last_avail(vq) ((vq)->last_avail_idx)
-
-/*
- * The virtio configuration space is defined to be little-endian. x86 is
- * little-endian too, but it's nice to be explicit so we have these helpers.
- */
-#define cpu_to_le16(v16) (v16)
-#define cpu_to_le32(v32) (v32)
-#define cpu_to_le64(v64) (v64)
-#define le16_to_cpu(v16) (v16)
-#define le32_to_cpu(v32) (v32)
-#define le64_to_cpu(v64) (v64)
-
-/*
- * A real device would ignore weird/non-compliant driver behaviour. We
- * stop and flag it, to help debugging Linux problems.
- */
-#define bad_driver(d, fmt, ...) \
- errx(1, "%s: bad driver: " fmt, (d)->name, ## __VA_ARGS__)
-#define bad_driver_vq(vq, fmt, ...) \
- errx(1, "%s vq %s: bad driver: " fmt, (vq)->dev->name, \
- vq->name, ## __VA_ARGS__)
-
-/* Is this iovec empty? */
-static bool iov_empty(const struct iovec iov[], unsigned int num_iov)
-{
- unsigned int i;
-
- for (i = 0; i < num_iov; i++)
- if (iov[i].iov_len)
- return false;
- return true;
-}
-
-/* Take len bytes from the front of this iovec. */
-static void iov_consume(struct device *d,
- struct iovec iov[], unsigned num_iov,
- void *dest, unsigned len)
-{
- unsigned int i;
-
- for (i = 0; i < num_iov; i++) {
- unsigned int used;
-
- used = iov[i].iov_len < len ? iov[i].iov_len : len;
- if (dest) {
- memcpy(dest, iov[i].iov_base, used);
- dest += used;
- }
- iov[i].iov_base += used;
- iov[i].iov_len -= used;
- len -= used;
- }
- if (len != 0)
- bad_driver(d, "iovec too short!");
-}
-
-/*L:100
- * The Launcher code itself takes us out into userspace, that scary place where
- * pointers run wild and free! Unfortunately, like most userspace programs,
- * it's quite boring (which is why everyone likes to hack on the kernel!).
- * Perhaps if you make up an Lguest Drinking Game at this point, it will get
- * you through this section. Or, maybe not.
- *
- * The Launcher sets up a big chunk of memory to be the Guest's "physical"
- * memory and stores it in "guest_base". In other words, Guest physical ==
- * Launcher virtual with an offset.
- *
- * This can be tough to get your head around, but usually it just means that we
- * use these trivial conversion functions when the Guest gives us its
- * "physical" addresses:
- */
-static void *from_guest_phys(unsigned long addr)
-{
- return guest_base + addr;
-}
-
-static unsigned long to_guest_phys(const void *addr)
-{
- return (addr - guest_base);
-}
-
-/*L:130
- * Loading the Kernel.
- *
- * We start with couple of simple helper routines. open_or_die() avoids
- * error-checking code cluttering the callers:
- */
-static int open_or_die(const char *name, int flags)
-{
- int fd = open(name, flags);
- if (fd < 0)
- err(1, "Failed to open %s", name);
- return fd;
-}
-
-/* map_zeroed_pages() takes a number of pages. */
-static void *map_zeroed_pages(unsigned int num)
-{
- int fd = open_or_die("/dev/zero", O_RDONLY);
- void *addr;
-
- /*
- * We use a private mapping (ie. if we write to the page, it will be
- * copied). We allocate an extra two pages PROT_NONE to act as guard
- * pages against read/write attempts that exceed allocated space.
- */
- addr = mmap(NULL, getpagesize() * (num+2),
- PROT_NONE, MAP_PRIVATE, fd, 0);
-
- if (addr == MAP_FAILED)
- err(1, "Mmapping %u pages of /dev/zero", num);
-
- if (mprotect(addr + getpagesize(), getpagesize() * num,
- PROT_READ|PROT_WRITE) == -1)
- err(1, "mprotect rw %u pages failed", num);
-
- /*
- * One neat mmap feature is that you can close the fd, and it
- * stays mapped.
- */
- close(fd);
-
- /* Return address after PROT_NONE page */
- return addr + getpagesize();
-}
-
-/* Get some bytes which won't be mapped into the guest. */
-static unsigned long get_mmio_region(size_t size)
-{
- unsigned long addr = guest_mmio;
- size_t i;
-
- if (!size)
- return addr;
-
- /* Size has to be a power of 2 (and multiple of 16) */
- for (i = 1; i < size; i <<= 1);
-
- guest_mmio += i;
-
- return addr;
-}
-
-/*
- * This routine is used to load the kernel or initrd. It tries mmap, but if
- * that fails (Plan 9's kernel file isn't nicely aligned on page boundaries),
- * it falls back to reading the memory in.
- */
-static void map_at(int fd, void *addr, unsigned long offset, unsigned long len)
-{
- ssize_t r;
-
- /*
- * We map writable even though for some segments are marked read-only.
- * The kernel really wants to be writable: it patches its own
- * instructions.
- *
- * MAP_PRIVATE means that the page won't be copied until a write is
- * done to it. This allows us to share untouched memory between
- * Guests.
- */
- if (mmap(addr, len, PROT_READ|PROT_WRITE,
- MAP_FIXED|MAP_PRIVATE, fd, offset) != MAP_FAILED)
- return;
-
- /* pread does a seek and a read in one shot: saves a few lines. */
- r = pread(fd, addr, len, offset);
- if (r != len)
- err(1, "Reading offset %lu len %lu gave %zi", offset, len, r);
-}
-
-/*
- * This routine takes an open vmlinux image, which is in ELF, and maps it into
- * the Guest memory. ELF = Embedded Linking Format, which is the format used
- * by all modern binaries on Linux including the kernel.
- *
- * The ELF headers give *two* addresses: a physical address, and a virtual
- * address. We use the physical address; the Guest will map itself to the
- * virtual address.
- *
- * We return the starting address.
- */
-static unsigned long map_elf(int elf_fd, const Elf32_Ehdr *ehdr)
-{
- Elf32_Phdr phdr[ehdr->e_phnum];
- unsigned int i;
-
- /*
- * Sanity checks on the main ELF header: an x86 executable with a
- * reasonable number of correctly-sized program headers.
- */
- if (ehdr->e_type != ET_EXEC
- || ehdr->e_machine != EM_386
- || ehdr->e_phentsize != sizeof(Elf32_Phdr)
- || ehdr->e_phnum < 1 || ehdr->e_phnum > 65536U/sizeof(Elf32_Phdr))
- errx(1, "Malformed elf header");
-
- /*
- * An ELF executable contains an ELF header and a number of "program"
- * headers which indicate which parts ("segments") of the program to
- * load where.
- */
-
- /* We read in all the program headers at once: */
- if (lseek(elf_fd, ehdr->e_phoff, SEEK_SET) < 0)
- err(1, "Seeking to program headers");
- if (read(elf_fd, phdr, sizeof(phdr)) != sizeof(phdr))
- err(1, "Reading program headers");
-
- /*
- * Try all the headers: there are usually only three. A read-only one,
- * a read-write one, and a "note" section which we don't load.
- */
- for (i = 0; i < ehdr->e_phnum; i++) {
- /* If this isn't a loadable segment, we ignore it */
- if (phdr[i].p_type != PT_LOAD)
- continue;
-
- verbose("Section %i: size %i addr %p\n",
- i, phdr[i].p_memsz, (void *)phdr[i].p_paddr);
-
- /* We map this section of the file at its physical address. */
- map_at(elf_fd, from_guest_phys(phdr[i].p_paddr),
- phdr[i].p_offset, phdr[i].p_filesz);
- }
-
- /* The entry point is given in the ELF header. */
- return ehdr->e_entry;
-}
-
-/*L:150
- * A bzImage, unlike an ELF file, is not meant to be loaded. You're supposed
- * to jump into it and it will unpack itself. We used to have to perform some
- * hairy magic because the unpacking code scared me.
- *
- * Fortunately, Jeremy Fitzhardinge convinced me it wasn't that hard and wrote
- * a small patch to jump over the tricky bits in the Guest, so now we just read
- * the funky header so we know where in the file to load, and away we go!
- */
-static unsigned long load_bzimage(int fd)
-{
- struct boot_params boot;
- int r;
- /* Modern bzImages get loaded at 1M. */
- void *p = from_guest_phys(0x100000);
-
- /*
- * Go back to the start of the file and read the header. It should be
- * a Linux boot header (see Documentation/x86/boot.txt)
- */
- lseek(fd, 0, SEEK_SET);
- read(fd, &boot, sizeof(boot));
-
- /* Inside the setup_hdr, we expect the magic "HdrS" */
- if (memcmp(&boot.hdr.header, "HdrS", 4) != 0)
- errx(1, "This doesn't look like a bzImage to me");
-
- /* Skip over the extra sectors of the header. */
- lseek(fd, (boot.hdr.setup_sects+1) * 512, SEEK_SET);
-
- /* Now read everything into memory. in nice big chunks. */
- while ((r = read(fd, p, 65536)) > 0)
- p += r;
-
- /* Finally, code32_start tells us where to enter the kernel. */
- return boot.hdr.code32_start;
-}
-
-/*L:140
- * Loading the kernel is easy when it's a "vmlinux", but most kernels
- * come wrapped up in the self-decompressing "bzImage" format. With a little
- * work, we can load those, too.
- */
-static unsigned long load_kernel(int fd)
-{
- Elf32_Ehdr hdr;
-
- /* Read in the first few bytes. */
- if (read(fd, &hdr, sizeof(hdr)) != sizeof(hdr))
- err(1, "Reading kernel");
-
- /* If it's an ELF file, it starts with "\177ELF" */
- if (memcmp(hdr.e_ident, ELFMAG, SELFMAG) == 0)
- return map_elf(fd, &hdr);
-
- /* Otherwise we assume it's a bzImage, and try to load it. */
- return load_bzimage(fd);
-}
-
-/*
- * This is a trivial little helper to align pages. Andi Kleen hated it because
- * it calls getpagesize() twice: "it's dumb code."
- *
- * Kernel guys get really het up about optimization, even when it's not
- * necessary. I leave this code as a reaction against that.
- */
-static inline unsigned long page_align(unsigned long addr)
-{
- /* Add upwards and truncate downwards. */
- return ((addr + getpagesize()-1) & ~(getpagesize()-1));
-}
-
-/*L:180
- * An "initial ram disk" is a disk image loaded into memory along with the
- * kernel which the kernel can use to boot from without needing any drivers.
- * Most distributions now use this as standard: the initrd contains the code to
- * load the appropriate driver modules for the current machine.
- *
- * Importantly, James Morris works for RedHat, and Fedora uses initrds for its
- * kernels. He sent me this (and tells me when I break it).
- */
-static unsigned long load_initrd(const char *name, unsigned long mem)
-{
- int ifd;
- struct stat st;
- unsigned long len;
-
- ifd = open_or_die(name, O_RDONLY);
- /* fstat() is needed to get the file size. */
- if (fstat(ifd, &st) < 0)
- err(1, "fstat() on initrd '%s'", name);
-
- /*
- * We map the initrd at the top of memory, but mmap wants it to be
- * page-aligned, so we round the size up for that.
- */
- len = page_align(st.st_size);
- map_at(ifd, from_guest_phys(mem - len), 0, st.st_size);
- /*
- * Once a file is mapped, you can close the file descriptor. It's a
- * little odd, but quite useful.
- */
- close(ifd);
- verbose("mapped initrd %s size=%lu @ %p\n", name, len, (void*)mem-len);
-
- /* We return the initrd size. */
- return len;
-}
-/*:*/
-
-/*
- * Simple routine to roll all the commandline arguments together with spaces
- * between them.
- */
-static void concat(char *dst, char *args[])
-{
- unsigned int i, len = 0;
-
- for (i = 0; args[i]; i++) {
- if (i) {
- strcat(dst+len, " ");
- len++;
- }
- strcpy(dst+len, args[i]);
- len += strlen(args[i]);
- }
- /* In case it's empty. */
- dst[len] = '\0';
-}
-
-/*L:185
- * This is where we actually tell the kernel to initialize the Guest. We
- * saw the arguments it expects when we looked at initialize() in lguest_user.c:
- * the base of Guest "physical" memory, the top physical page to allow and the
- * entry point for the Guest.
- */
-static void tell_kernel(unsigned long start)
-{
- unsigned long args[] = { LHREQ_INITIALIZE,
- (unsigned long)guest_base,
- guest_limit / getpagesize(), start,
- (guest_mmio+getpagesize()-1) / getpagesize() };
- verbose("Guest: %p - %p (%#lx, MMIO %#lx)\n",
- guest_base, guest_base + guest_limit,
- guest_limit, guest_mmio);
- lguest_fd = open_or_die("/dev/lguest", O_RDWR);
- if (write(lguest_fd, args, sizeof(args)) < 0)
- err(1, "Writing to /dev/lguest");
-}
-/*:*/
-
-/*L:200
- * Device Handling.
- *
- * When the Guest gives us a buffer, it sends an array of addresses and sizes.
- * We need to make sure it's not trying to reach into the Launcher itself, so
- * we have a convenient routine which checks it and exits with an error message
- * if something funny is going on:
- */
-static void *_check_pointer(struct device *d,
- unsigned long addr, unsigned int size,
- unsigned int line)
-{
- /*
- * Check if the requested address and size exceeds the allocated memory,
- * or addr + size wraps around.
- */
- if ((addr + size) > guest_limit || (addr + size) < addr)
- bad_driver(d, "%s:%i: Invalid address %#lx",
- __FILE__, line, addr);
- /*
- * We return a pointer for the caller's convenience, now we know it's
- * safe to use.
- */
- return from_guest_phys(addr);
-}
-/* A macro which transparently hands the line number to the real function. */
-#define check_pointer(d,addr,size) _check_pointer(d, addr, size, __LINE__)
-
-/*
- * Each buffer in the virtqueues is actually a chain of descriptors. This
- * function returns the next descriptor in the chain, or vq->vring.num if we're
- * at the end.
- */
-static unsigned next_desc(struct device *d, struct vring_desc *desc,
- unsigned int i, unsigned int max)
-{
- unsigned int next;
-
- /* If this descriptor says it doesn't chain, we're done. */
- if (!(desc[i].flags & VRING_DESC_F_NEXT))
- return max;
-
- /* Check they're not leading us off end of descriptors. */
- next = desc[i].next;
- /* Make sure compiler knows to grab that: we don't want it changing! */
- wmb();
-
- if (next >= max)
- bad_driver(d, "Desc next is %u", next);
-
- return next;
-}
-
-/*
- * This actually sends the interrupt for this virtqueue, if we've used a
- * buffer.
- */
-static void trigger_irq(struct virtqueue *vq)
-{
- unsigned long buf[] = { LHREQ_IRQ, vq->dev->config.irq_line };
-
- /* Don't inform them if nothing used. */
- if (!vq->pending_used)
- return;
- vq->pending_used = 0;
-
- /*
- * 2.4.7.1:
- *
- * If the VIRTIO_F_EVENT_IDX feature bit is not negotiated:
- * The driver MUST set flags to 0 or 1.
- */
- if (vq->vring.avail->flags > 1)
- bad_driver_vq(vq, "avail->flags = %u\n", vq->vring.avail->flags);
-
- /*
- * 2.4.7.2:
- *
- * If the VIRTIO_F_EVENT_IDX feature bit is not negotiated:
- *
- * - The device MUST ignore the used_event value.
- * - After the device writes a descriptor index into the used ring:
- * - If flags is 1, the device SHOULD NOT send an interrupt.
- * - If flags is 0, the device MUST send an interrupt.
- */
- if (vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT) {
- return;
- }
-
- /*
- * 4.1.4.5.1:
- *
- * If MSI-X capability is disabled, the device MUST set the Queue
- * Interrupt bit in ISR status before sending a virtqueue notification
- * to the driver.
- */
- vq->dev->mmio->isr = 0x1;
-
- /* Send the Guest an interrupt tell them we used something up. */
- if (write(lguest_fd, buf, sizeof(buf)) != 0)
- err(1, "Triggering irq %i", vq->dev->config.irq_line);
-}
-
-/*
- * This looks in the virtqueue for the first available buffer, and converts
- * it to an iovec for convenient access. Since descriptors consist of some
- * number of output then some number of input descriptors, it's actually two
- * iovecs, but we pack them into one and note how many of each there were.
- *
- * This function waits if necessary, and returns the descriptor number found.
- */
-static unsigned wait_for_vq_desc(struct virtqueue *vq,
- struct iovec iov[],
- unsigned int *out_num, unsigned int *in_num)
-{
- unsigned int i, head, max;
- struct vring_desc *desc;
- u16 last_avail = lg_last_avail(vq);
-
- /*
- * 2.4.7.1:
- *
- * The driver MUST handle spurious interrupts from the device.
- *
- * That's why this is a while loop.
- */
-
- /* There's nothing available? */
- while (last_avail == vq->vring.avail->idx) {
- u64 event;
-
- /*
- * Since we're about to sleep, now is a good time to tell the
- * Guest about what we've used up to now.
- */
- trigger_irq(vq);
-
- /* OK, now we need to know about added descriptors. */
- vq->vring.used->flags &= ~VRING_USED_F_NO_NOTIFY;
-
- /*
- * They could have slipped one in as we were doing that: make
- * sure it's written, then check again.
- */
- mb();
- if (last_avail != vq->vring.avail->idx) {
- vq->vring.used->flags |= VRING_USED_F_NO_NOTIFY;
- break;
- }
-
- /* Nothing new? Wait for eventfd to tell us they refilled. */
- if (read(vq->eventfd, &event, sizeof(event)) != sizeof(event))
- errx(1, "Event read failed?");
-
- /* We don't need to be notified again. */
- vq->vring.used->flags |= VRING_USED_F_NO_NOTIFY;
- }
-
- /* Check it isn't doing very strange things with descriptor numbers. */
- if ((u16)(vq->vring.avail->idx - last_avail) > vq->vring.num)
- bad_driver_vq(vq, "Guest moved used index from %u to %u",
- last_avail, vq->vring.avail->idx);
-
- /*
- * Make sure we read the descriptor number *after* we read the ring
- * update; don't let the cpu or compiler change the order.
- */
- rmb();
-
- /*
- * Grab the next descriptor number they're advertising, and increment
- * the index we've seen.
- */
- head = vq->vring.avail->ring[last_avail % vq->vring.num];
- lg_last_avail(vq)++;
-
- /* If their number is silly, that's a fatal mistake. */
- if (head >= vq->vring.num)
- bad_driver_vq(vq, "Guest says index %u is available", head);
-
- /* When we start there are none of either input nor output. */
- *out_num = *in_num = 0;
-
- max = vq->vring.num;
- desc = vq->vring.desc;
- i = head;
-
- /*
- * We have to read the descriptor after we read the descriptor number,
- * but there's a data dependency there so the CPU shouldn't reorder
- * that: no rmb() required.
- */
-
- do {
- /*
- * If this is an indirect entry, then this buffer contains a
- * descriptor table which we handle as if it's any normal
- * descriptor chain.
- */
- if (desc[i].flags & VRING_DESC_F_INDIRECT) {
- /* 2.4.5.3.1:
- *
- * The driver MUST NOT set the VIRTQ_DESC_F_INDIRECT
- * flag unless the VIRTIO_F_INDIRECT_DESC feature was
- * negotiated.
- */
- if (!(vq->dev->features_accepted &
- (1<<VIRTIO_RING_F_INDIRECT_DESC)))
- bad_driver_vq(vq, "vq indirect not negotiated");
-
- /*
- * 2.4.5.3.1:
- *
- * The driver MUST NOT set the VIRTQ_DESC_F_INDIRECT
- * flag within an indirect descriptor (ie. only one
- * table per descriptor).
- */
- if (desc != vq->vring.desc)
- bad_driver_vq(vq, "Indirect within indirect");
-
- /*
- * Proposed update VIRTIO-134 spells this out:
- *
- * A driver MUST NOT set both VIRTQ_DESC_F_INDIRECT
- * and VIRTQ_DESC_F_NEXT in flags.
- */
- if (desc[i].flags & VRING_DESC_F_NEXT)
- bad_driver_vq(vq, "indirect and next together");
-
- if (desc[i].len % sizeof(struct vring_desc))
- bad_driver_vq(vq,
- "Invalid size for indirect table");
- /*
- * 2.4.5.3.2:
- *
- * The device MUST ignore the write-only flag
- * (flags&VIRTQ_DESC_F_WRITE) in the descriptor that
- * refers to an indirect table.
- *
- * We ignore it here: :)
- */
-
- max = desc[i].len / sizeof(struct vring_desc);
- desc = check_pointer(vq->dev, desc[i].addr, desc[i].len);
- i = 0;
-
- /* 2.4.5.3.1:
- *
- * A driver MUST NOT create a descriptor chain longer
- * than the Queue Size of the device.
- */
- if (max > vq->pci_config.queue_size)
- bad_driver_vq(vq,
- "indirect has too many entries");
- }
-
- /* Grab the first descriptor, and check it's OK. */
- iov[*out_num + *in_num].iov_len = desc[i].len;
- iov[*out_num + *in_num].iov_base
- = check_pointer(vq->dev, desc[i].addr, desc[i].len);
- /* If this is an input descriptor, increment that count. */
- if (desc[i].flags & VRING_DESC_F_WRITE)
- (*in_num)++;
- else {
- /*
- * If it's an output descriptor, they're all supposed
- * to come before any input descriptors.
- */
- if (*in_num)
- bad_driver_vq(vq,
- "Descriptor has out after in");
- (*out_num)++;
- }
-
- /* If we've got too many, that implies a descriptor loop. */
- if (*out_num + *in_num > max)
- bad_driver_vq(vq, "Looped descriptor");
- } while ((i = next_desc(vq->dev, desc, i, max)) != max);
-
- return head;
-}
-
-/*
- * After we've used one of their buffers, we tell the Guest about it. Sometime
- * later we'll want to send them an interrupt using trigger_irq(); note that
- * wait_for_vq_desc() does that for us if it has to wait.
- */
-static void add_used(struct virtqueue *vq, unsigned int head, int len)
-{
- struct vring_used_elem *used;
-
- /*
- * The virtqueue contains a ring of used buffers. Get a pointer to the
- * next entry in that used ring.
- */
- used = &vq->vring.used->ring[vq->vring.used->idx % vq->vring.num];
- used->id = head;
- used->len = len;
- /* Make sure buffer is written before we update index. */
- wmb();
- vq->vring.used->idx++;
- vq->pending_used++;
-}
-
-/* And here's the combo meal deal. Supersize me! */
-static void add_used_and_trigger(struct virtqueue *vq, unsigned head, int len)
-{
- add_used(vq, head, len);
- trigger_irq(vq);
-}
-
-/*
- * The Console
- *
- * We associate some data with the console for our exit hack.
- */
-struct console_abort {
- /* How many times have they hit ^C? */
- int count;
- /* When did they start? */
- struct timeval start;
-};
-
-/* This is the routine which handles console input (ie. stdin). */
-static void console_input(struct virtqueue *vq)
-{
- int len;
- unsigned int head, in_num, out_num;
- struct console_abort *abort = vq->dev->priv;
- struct iovec iov[vq->vring.num];
-
- /* Make sure there's a descriptor available. */
- head = wait_for_vq_desc(vq, iov, &out_num, &in_num);
- if (out_num)
- bad_driver_vq(vq, "Output buffers in console in queue?");
-
- /* Read into it. This is where we usually wait. */
- len = readv(STDIN_FILENO, iov, in_num);
- if (len <= 0) {
- /* Ran out of input? */
- warnx("Failed to get console input, ignoring console.");
- /*
- * For simplicity, dying threads kill the whole Launcher. So
- * just nap here.
- */
- for (;;)
- pause();
- }
-
- /* Tell the Guest we used a buffer. */
- add_used_and_trigger(vq, head, len);
-
- /*
- * Three ^C within one second? Exit.
- *
- * This is such a hack, but works surprisingly well. Each ^C has to
- * be in a buffer by itself, so they can't be too fast. But we check
- * that we get three within about a second, so they can't be too
- * slow.
- */
- if (len != 1 || ((char *)iov[0].iov_base)[0] != 3) {
- abort->count = 0;
- return;
- }
-
- abort->count++;
- if (abort->count == 1)
- gettimeofday(&abort->start, NULL);
- else if (abort->count == 3) {
- struct timeval now;
- gettimeofday(&now, NULL);
- /* Kill all Launcher processes with SIGINT, like normal ^C */
- if (now.tv_sec <= abort->start.tv_sec+1)
- kill(0, SIGINT);
- abort->count = 0;
- }
-}
-
-/* This is the routine which handles console output (ie. stdout). */
-static void console_output(struct virtqueue *vq)
-{
- unsigned int head, out, in;
- struct iovec iov[vq->vring.num];
-
- /* We usually wait in here, for the Guest to give us something. */
- head = wait_for_vq_desc(vq, iov, &out, &in);
- if (in)
- bad_driver_vq(vq, "Input buffers in console output queue?");
-
- /* writev can return a partial write, so we loop here. */
- while (!iov_empty(iov, out)) {
- int len = writev(STDOUT_FILENO, iov, out);
- if (len <= 0) {
- warn("Write to stdout gave %i (%d)", len, errno);
- break;
- }
- iov_consume(vq->dev, iov, out, NULL, len);
- }
-
- /*
- * We're finished with that buffer: if we're going to sleep,
- * wait_for_vq_desc() will prod the Guest with an interrupt.
- */
- add_used(vq, head, 0);
-}
-
-/*
- * The Network
- *
- * Handling output for network is also simple: we get all the output buffers
- * and write them to /dev/net/tun.
- */
-struct net_info {
- int tunfd;
-};
-
-static void net_output(struct virtqueue *vq)
-{
- struct net_info *net_info = vq->dev->priv;
- unsigned int head, out, in;
- struct iovec iov[vq->vring.num];
-
- /* We usually wait in here for the Guest to give us a packet. */
- head = wait_for_vq_desc(vq, iov, &out, &in);
- if (in)
- bad_driver_vq(vq, "Input buffers in net output queue?");
- /*
- * Send the whole thing through to /dev/net/tun. It expects the exact
- * same format: what a coincidence!
- */
- if (writev(net_info->tunfd, iov, out) < 0)
- warnx("Write to tun failed (%d)?", errno);
-
- /*
- * Done with that one; wait_for_vq_desc() will send the interrupt if
- * all packets are processed.
- */
- add_used(vq, head, 0);
-}
-
-/*
- * Handling network input is a bit trickier, because I've tried to optimize it.
- *
- * First we have a helper routine which tells is if from this file descriptor
- * (ie. the /dev/net/tun device) will block:
- */
-static bool will_block(int fd)
-{
- fd_set fdset;
- struct timeval zero = { 0, 0 };
- FD_ZERO(&fdset);
- FD_SET(fd, &fdset);
- return select(fd+1, &fdset, NULL, NULL, &zero) != 1;
-}
-
-/*
- * This handles packets coming in from the tun device to our Guest. Like all
- * service routines, it gets called again as soon as it returns, so you don't
- * see a while(1) loop here.
- */
-static void net_input(struct virtqueue *vq)
-{
- int len;
- unsigned int head, out, in;
- struct iovec iov[vq->vring.num];
- struct net_info *net_info = vq->dev->priv;
-
- /*
- * Get a descriptor to write an incoming packet into. This will also
- * send an interrupt if they're out of descriptors.
- */
- head = wait_for_vq_desc(vq, iov, &out, &in);
- if (out)
- bad_driver_vq(vq, "Output buffers in net input queue?");
-
- /*
- * If it looks like we'll block reading from the tun device, send them
- * an interrupt.
- */
- if (vq->pending_used && will_block(net_info->tunfd))
- trigger_irq(vq);
-
- /*
- * Read in the packet. This is where we normally wait (when there's no
- * incoming network traffic).
- */
- len = readv(net_info->tunfd, iov, in);
- if (len <= 0)
- warn("Failed to read from tun (%d).", errno);
-
- /*
- * Mark that packet buffer as used, but don't interrupt here. We want
- * to wait until we've done as much work as we can.
- */
- add_used(vq, head, len);
-}
-/*:*/
-
-/* This is the helper to create threads: run the service routine in a loop. */
-static int do_thread(void *_vq)
-{
- struct virtqueue *vq = _vq;
-
- for (;;)
- vq->service(vq);
- return 0;
-}
-
-/*
- * When a child dies, we kill our entire process group with SIGTERM. This
- * also has the side effect that the shell restores the console for us!
- */
-static void kill_launcher(int signal)
-{
- kill(0, SIGTERM);
-}
-
-static void reset_vq_pci_config(struct virtqueue *vq)
-{
- vq->pci_config.queue_size = VIRTQUEUE_NUM;
- vq->pci_config.queue_enable = 0;
-}
-
-static void reset_device(struct device *dev)
-{
- struct virtqueue *vq;
-
- verbose("Resetting device %s\n", dev->name);
-
- /* Clear any features they've acked. */
- dev->features_accepted = 0;
-
- /* We're going to be explicitly killing threads, so ignore them. */
- signal(SIGCHLD, SIG_IGN);
-
- /*
- * 4.1.4.3.1:
- *
- * The device MUST present a 0 in queue_enable on reset.
- *
- * This means we set it here, and reset the saved ones in every vq.
- */
- dev->mmio->cfg.queue_enable = 0;
-
- /* Get rid of the virtqueue threads */
- for (vq = dev->vq; vq; vq = vq->next) {
- vq->last_avail_idx = 0;
- reset_vq_pci_config(vq);
- if (vq->thread != (pid_t)-1) {
- kill(vq->thread, SIGTERM);
- waitpid(vq->thread, NULL, 0);
- vq->thread = (pid_t)-1;
- }
- }
- dev->running = false;
- dev->wrote_features_ok = false;
-
- /* Now we care if threads die. */
- signal(SIGCHLD, (void *)kill_launcher);
-}
-
-static void cleanup_devices(void)
-{
- unsigned int i;
-
- for (i = 1; i < MAX_PCI_DEVICES; i++) {
- struct device *d = devices.pci[i];
- if (!d)
- continue;
- reset_device(d);
- }
-
- /* If we saved off the original terminal settings, restore them now. */
- if (orig_term.c_lflag & (ISIG|ICANON|ECHO))
- tcsetattr(STDIN_FILENO, TCSANOW, &orig_term);
-}
-
-/*L:217
- * We do PCI. This is mainly done to let us test the kernel virtio PCI
- * code.
- */
-
-/* Linux expects a PCI host bridge: ours is a dummy, and first on the bus. */
-static struct device pci_host_bridge;
-
-static void init_pci_host_bridge(void)
-{
- pci_host_bridge.name = "PCI Host Bridge";
- pci_host_bridge.config.class = 0x06; /* bridge */
- pci_host_bridge.config.subclass = 0; /* host bridge */
- devices.pci[0] = &pci_host_bridge;
-}
-
-/* The IO ports used to read the PCI config space. */
-#define PCI_CONFIG_ADDR 0xCF8
-#define PCI_CONFIG_DATA 0xCFC
-
-/*
- * Not really portable, but does help readability: this is what the Guest
- * writes to the PCI_CONFIG_ADDR IO port.
- */
-union pci_config_addr {
- struct {
- unsigned mbz: 2;
- unsigned offset: 6;
- unsigned funcnum: 3;
- unsigned devnum: 5;
- unsigned busnum: 8;
- unsigned reserved: 7;
- unsigned enabled : 1;
- } bits;
- u32 val;
-};
-
-/*
- * We cache what they wrote to the address port, so we know what they're
- * talking about when they access the data port.
- */
-static union pci_config_addr pci_config_addr;
-
-static struct device *find_pci_device(unsigned int index)
-{
- return devices.pci[index];
-}
-
-/* PCI can do 1, 2 and 4 byte reads; we handle that here. */
-static void ioread(u16 off, u32 v, u32 mask, u32 *val)
-{
- assert(off < 4);
- assert(mask == 0xFF || mask == 0xFFFF || mask == 0xFFFFFFFF);
- *val = (v >> (off * 8)) & mask;
-}
-
-/* PCI can do 1, 2 and 4 byte writes; we handle that here. */
-static void iowrite(u16 off, u32 v, u32 mask, u32 *dst)
-{
- assert(off < 4);
- assert(mask == 0xFF || mask == 0xFFFF || mask == 0xFFFFFFFF);
- *dst &= ~(mask << (off * 8));
- *dst |= (v & mask) << (off * 8);
-}
-
-/*
- * Where PCI_CONFIG_DATA accesses depends on the previous write to
- * PCI_CONFIG_ADDR.
- */
-static struct device *dev_and_reg(u32 *reg)
-{
- if (!pci_config_addr.bits.enabled)
- return NULL;
-
- if (pci_config_addr.bits.funcnum != 0)
- return NULL;
-
- if (pci_config_addr.bits.busnum != 0)
- return NULL;
-
- if (pci_config_addr.bits.offset * 4 >= sizeof(struct pci_config))
- return NULL;
-
- *reg = pci_config_addr.bits.offset;
- return find_pci_device(pci_config_addr.bits.devnum);
-}
-
-/*
- * We can get invalid combinations of values while they're writing, so we
- * only fault if they try to write with some invalid bar/offset/length.
- */
-static bool valid_bar_access(struct device *d,
- struct virtio_pci_cfg_cap_u32 *cfg_access)
-{
- /* We only have 1 bar (BAR0) */
- if (cfg_access->cap.bar != 0)
- return false;
-
- /* Check it's within BAR0. */
- if (cfg_access->cap.offset >= d->mmio_size
- || cfg_access->cap.offset + cfg_access->cap.length > d->mmio_size)
- return false;
-
- /* Check length is 1, 2 or 4. */
- if (cfg_access->cap.length != 1
- && cfg_access->cap.length != 2
- && cfg_access->cap.length != 4)
- return false;
-
- /*
- * 4.1.4.7.2:
- *
- * The driver MUST NOT write a cap.offset which is not a multiple of
- * cap.length (ie. all accesses MUST be aligned).
- */
- if (cfg_access->cap.offset % cfg_access->cap.length != 0)
- return false;
-
- /* Return pointer into word in BAR0. */
- return true;
-}
-
-/* Is this accessing the PCI config address port?. */
-static bool is_pci_addr_port(u16 port)
-{
- return port >= PCI_CONFIG_ADDR && port < PCI_CONFIG_ADDR + 4;
-}
-
-static bool pci_addr_iowrite(u16 port, u32 mask, u32 val)
-{
- iowrite(port - PCI_CONFIG_ADDR, val, mask,
- &pci_config_addr.val);
- verbose("PCI%s: %#x/%x: bus %u dev %u func %u reg %u\n",
- pci_config_addr.bits.enabled ? "" : " DISABLED",
- val, mask,
- pci_config_addr.bits.busnum,
- pci_config_addr.bits.devnum,
- pci_config_addr.bits.funcnum,
- pci_config_addr.bits.offset);
- return true;
-}
-
-static void pci_addr_ioread(u16 port, u32 mask, u32 *val)
-{
- ioread(port - PCI_CONFIG_ADDR, pci_config_addr.val, mask, val);
-}
-
-/* Is this accessing the PCI config data port?. */
-static bool is_pci_data_port(u16 port)
-{
- return port >= PCI_CONFIG_DATA && port < PCI_CONFIG_DATA + 4;
-}
-
-static void emulate_mmio_write(struct device *d, u32 off, u32 val, u32 mask);
-
-static bool pci_data_iowrite(u16 port, u32 mask, u32 val)
-{
- u32 reg, portoff;
- struct device *d = dev_and_reg(®);
-
- /* Complain if they don't belong to a device. */
- if (!d)
- return false;
-
- /* They can do 1 byte writes, etc. */
- portoff = port - PCI_CONFIG_DATA;
-
- /*
- * PCI uses a weird way to determine the BAR size: the OS
- * writes all 1's, and sees which ones stick.
- */
- if (&d->config_words[reg] == &d->config.bar[0]) {
- int i;
-
- iowrite(portoff, val, mask, &d->config.bar[0]);
- for (i = 0; (1 << i) < d->mmio_size; i++)
- d->config.bar[0] &= ~(1 << i);
- return true;
- } else if ((&d->config_words[reg] > &d->config.bar[0]
- && &d->config_words[reg] <= &d->config.bar[6])
- || &d->config_words[reg] == &d->config.expansion_rom_addr) {
- /* Allow writing to any other BAR, or expansion ROM */
- iowrite(portoff, val, mask, &d->config_words[reg]);
- return true;
- /* We let them override latency timer and cacheline size */
- } else if (&d->config_words[reg] == (void *)&d->config.cacheline_size) {
- /* Only let them change the first two fields. */
- if (mask == 0xFFFFFFFF)
- mask = 0xFFFF;
- iowrite(portoff, val, mask, &d->config_words[reg]);
- return true;
- } else if (&d->config_words[reg] == (void *)&d->config.command
- && mask == 0xFFFF) {
- /* Ignore command writes. */
- return true;
- } else if (&d->config_words[reg]
- == (void *)&d->config.cfg_access.cap.bar
- || &d->config_words[reg]
- == &d->config.cfg_access.cap.length
- || &d->config_words[reg]
- == &d->config.cfg_access.cap.offset) {
-
- /*
- * The VIRTIO_PCI_CAP_PCI_CFG capability
- * provides a backdoor to access the MMIO
- * regions without mapping them. Weird, but
- * useful.
- */
- iowrite(portoff, val, mask, &d->config_words[reg]);
- return true;
- } else if (&d->config_words[reg] == &d->config.cfg_access.pci_cfg_data) {
- u32 write_mask;
-
- /*
- * 4.1.4.7.1:
- *
- * Upon detecting driver write access to pci_cfg_data, the
- * device MUST execute a write access at offset cap.offset at
- * BAR selected by cap.bar using the first cap.length bytes
- * from pci_cfg_data.
- */
-
- /* Must be bar 0 */
- if (!valid_bar_access(d, &d->config.cfg_access))
- return false;
-
- iowrite(portoff, val, mask, &d->config.cfg_access.pci_cfg_data);
-
- /*
- * Now emulate a write. The mask we use is set by
- * len, *not* this write!
- */
- write_mask = (1ULL<<(8*d->config.cfg_access.cap.length)) - 1;
- verbose("Window writing %#x/%#x to bar %u, offset %u len %u\n",
- d->config.cfg_access.pci_cfg_data, write_mask,
- d->config.cfg_access.cap.bar,
- d->config.cfg_access.cap.offset,
- d->config.cfg_access.cap.length);
-
- emulate_mmio_write(d, d->config.cfg_access.cap.offset,
- d->config.cfg_access.pci_cfg_data,
- write_mask);
- return true;
- }
-
- /*
- * 4.1.4.1:
- *
- * The driver MUST NOT write into any field of the capability
- * structure, with the exception of those with cap_type
- * VIRTIO_PCI_CAP_PCI_CFG...
- */
- return false;
-}
-
-static u32 emulate_mmio_read(struct device *d, u32 off, u32 mask);
-
-static void pci_data_ioread(u16 port, u32 mask, u32 *val)
-{
- u32 reg;
- struct device *d = dev_and_reg(®);
-
- if (!d)
- return;
-
- /* Read through the PCI MMIO access window is special */
- if (&d->config_words[reg] == &d->config.cfg_access.pci_cfg_data) {
- u32 read_mask;
-
- /*
- * 4.1.4.7.1:
- *
- * Upon detecting driver read access to pci_cfg_data, the
- * device MUST execute a read access of length cap.length at
- * offset cap.offset at BAR selected by cap.bar and store the
- * first cap.length bytes in pci_cfg_data.
- */
- /* Must be bar 0 */
- if (!valid_bar_access(d, &d->config.cfg_access))
- bad_driver(d,
- "Invalid cfg_access to bar%u, offset %u len %u",
- d->config.cfg_access.cap.bar,
- d->config.cfg_access.cap.offset,
- d->config.cfg_access.cap.length);
-
- /*
- * Read into the window. The mask we use is set by
- * len, *not* this read!
- */
- read_mask = (1ULL<<(8*d->config.cfg_access.cap.length))-1;
- d->config.cfg_access.pci_cfg_data
- = emulate_mmio_read(d,
- d->config.cfg_access.cap.offset,
- read_mask);
- verbose("Window read %#x/%#x from bar %u, offset %u len %u\n",
- d->config.cfg_access.pci_cfg_data, read_mask,
- d->config.cfg_access.cap.bar,
- d->config.cfg_access.cap.offset,
- d->config.cfg_access.cap.length);
- }
- ioread(port - PCI_CONFIG_DATA, d->config_words[reg], mask, val);
-}
-
-/*L:216
- * This is where we emulate a handful of Guest instructions. It's ugly
- * and we used to do it in the kernel but it grew over time.
- */
-
-/*
- * We use the ptrace syscall's pt_regs struct to talk about registers
- * to lguest: these macros convert the names to the offsets.
- */
-#define getreg(name) getreg_off(offsetof(struct user_regs_struct, name))
-#define setreg(name, val) \
- setreg_off(offsetof(struct user_regs_struct, name), (val))
-
-static u32 getreg_off(size_t offset)
-{
- u32 r;
- unsigned long args[] = { LHREQ_GETREG, offset };
-
- if (pwrite(lguest_fd, args, sizeof(args), cpu_id) < 0)
- err(1, "Getting register %u", offset);
- if (pread(lguest_fd, &r, sizeof(r), cpu_id) != sizeof(r))
- err(1, "Reading register %u", offset);
-
- return r;
-}
-
-static void setreg_off(size_t offset, u32 val)
-{
- unsigned long args[] = { LHREQ_SETREG, offset, val };
-
- if (pwrite(lguest_fd, args, sizeof(args), cpu_id) < 0)
- err(1, "Setting register %u", offset);
-}
-
-/* Get register by instruction encoding */
-static u32 getreg_num(unsigned regnum, u32 mask)
-{
- /* 8 bit ops use regnums 4-7 for high parts of word */
- if (mask == 0xFF && (regnum & 0x4))
- return getreg_num(regnum & 0x3, 0xFFFF) >> 8;
-
- switch (regnum) {
- case 0: return getreg(eax) & mask;
- case 1: return getreg(ecx) & mask;
- case 2: return getreg(edx) & mask;
- case 3: return getreg(ebx) & mask;
- case 4: return getreg(esp) & mask;
- case 5: return getreg(ebp) & mask;
- case 6: return getreg(esi) & mask;
- case 7: return getreg(edi) & mask;
- }
- abort();
-}
-
-/* Set register by instruction encoding */
-static void setreg_num(unsigned regnum, u32 val, u32 mask)
-{
- /* Don't try to set bits out of range */
- assert(~(val & ~mask));
-
- /* 8 bit ops use regnums 4-7 for high parts of word */
- if (mask == 0xFF && (regnum & 0x4)) {
- /* Construct the 16 bits we want. */
- val = (val << 8) | getreg_num(regnum & 0x3, 0xFF);
- setreg_num(regnum & 0x3, val, 0xFFFF);
- return;
- }
-
- switch (regnum) {
- case 0: setreg(eax, val | (getreg(eax) & ~mask)); return;
- case 1: setreg(ecx, val | (getreg(ecx) & ~mask)); return;
- case 2: setreg(edx, val | (getreg(edx) & ~mask)); return;
- case 3: setreg(ebx, val | (getreg(ebx) & ~mask)); return;
- case 4: setreg(esp, val | (getreg(esp) & ~mask)); return;
- case 5: setreg(ebp, val | (getreg(ebp) & ~mask)); return;
- case 6: setreg(esi, val | (getreg(esi) & ~mask)); return;
- case 7: setreg(edi, val | (getreg(edi) & ~mask)); return;
- }
- abort();
-}
-
-/* Get bytes of displacement appended to instruction, from r/m encoding */
-static u32 insn_displacement_len(u8 mod_reg_rm)
-{
- /* Switch on the mod bits */
- switch (mod_reg_rm >> 6) {
- case 0:
- /* If mod == 0, and r/m == 101, 16-bit displacement follows */
- if ((mod_reg_rm & 0x7) == 0x5)
- return 2;
- /* Normally, mod == 0 means no literal displacement */
- return 0;
- case 1:
- /* One byte displacement */
- return 1;
- case 2:
- /* Four byte displacement */
- return 4;
- case 3:
- /* Register mode */
- return 0;
- }
- abort();
-}
-
-static void emulate_insn(const u8 insn[])
-{
- unsigned long args[] = { LHREQ_TRAP, 13 };
- unsigned int insnlen = 0, in = 0, small_operand = 0, byte_access;
- unsigned int eax, port, mask;
- /*
- * Default is to return all-ones on IO port reads, which traditionally
- * means "there's nothing there".
- */
- u32 val = 0xFFFFFFFF;
-
- /*
- * This must be the Guest kernel trying to do something, not userspace!
- * The bottom two bits of the CS segment register are the privilege
- * level.
- */
- if ((getreg(xcs) & 3) != 0x1)
- goto no_emulate;
-
- /* Decoding x86 instructions is icky. */
-
- /*
- * Around 2.6.33, the kernel started using an emulation for the
- * cmpxchg8b instruction in early boot on many configurations. This
- * code isn't paravirtualized, and it tries to disable interrupts.
- * Ignore it, which will Mostly Work.
- */
- if (insn[insnlen] == 0xfa) {
- /* "cli", or Clear Interrupt Enable instruction. Skip it. */
- insnlen = 1;
- goto skip_insn;
- }
-
- /*
- * 0x66 is an "operand prefix". It means a 16, not 32 bit in/out.
- */
- if (insn[insnlen] == 0x66) {
- small_operand = 1;
- /* The instruction is 1 byte so far, read the next byte. */
- insnlen = 1;
- }
-
- /* If the lower bit isn't set, it's a single byte access */
- byte_access = !(insn[insnlen] & 1);
-
- /*
- * Now we can ignore the lower bit and decode the 4 opcodes
- * we need to emulate.
- */
- switch (insn[insnlen] & 0xFE) {
- case 0xE4: /* in <next byte>,%al */
- port = insn[insnlen+1];
- insnlen += 2;
- in = 1;
- break;
- case 0xEC: /* in (%dx),%al */
- port = getreg(edx) & 0xFFFF;
- insnlen += 1;
- in = 1;
- break;
- case 0xE6: /* out %al,<next byte> */
- port = insn[insnlen+1];
- insnlen += 2;
- break;
- case 0xEE: /* out %al,(%dx) */
- port = getreg(edx) & 0xFFFF;
- insnlen += 1;
- break;
- default:
- /* OK, we don't know what this is, can't emulate. */
- goto no_emulate;
- }
-
- /* Set a mask of the 1, 2 or 4 bytes, depending on size of IO */
- if (byte_access)
- mask = 0xFF;
- else if (small_operand)
- mask = 0xFFFF;
- else
- mask = 0xFFFFFFFF;
-
- /*
- * If it was an "IN" instruction, they expect the result to be read
- * into %eax, so we change %eax.
- */
- eax = getreg(eax);
-
- if (in) {
- /* This is the PS/2 keyboard status; 1 means ready for output */
- if (port == 0x64)
- val = 1;
- else if (is_pci_addr_port(port))
- pci_addr_ioread(port, mask, &val);
- else if (is_pci_data_port(port))
- pci_data_ioread(port, mask, &val);
-
- /* Clear the bits we're about to read */
- eax &= ~mask;
- /* Copy bits in from val. */
- eax |= val & mask;
- /* Now update the register. */
- setreg(eax, eax);
- } else {
- if (is_pci_addr_port(port)) {
- if (!pci_addr_iowrite(port, mask, eax))
- goto bad_io;
- } else if (is_pci_data_port(port)) {
- if (!pci_data_iowrite(port, mask, eax))
- goto bad_io;
- }
- /* There are many other ports, eg. CMOS clock, serial
- * and parallel ports, so we ignore them all. */
- }
-
- verbose("IO %s of %x to %u: %#08x\n",
- in ? "IN" : "OUT", mask, port, eax);
-skip_insn:
- /* Finally, we've "done" the instruction, so move past it. */
- setreg(eip, getreg(eip) + insnlen);
- return;
-
-bad_io:
- warnx("Attempt to %s port %u (%#x mask)",
- in ? "read from" : "write to", port, mask);
-
-no_emulate:
- /* Inject trap into Guest. */
- if (write(lguest_fd, args, sizeof(args)) < 0)
- err(1, "Reinjecting trap 13 for fault at %#x", getreg(eip));
-}
-
-static struct device *find_mmio_region(unsigned long paddr, u32 *off)
-{
- unsigned int i;
-
- for (i = 1; i < MAX_PCI_DEVICES; i++) {
- struct device *d = devices.pci[i];
-
- if (!d)
- continue;
- if (paddr < d->mmio_addr)
- continue;
- if (paddr >= d->mmio_addr + d->mmio_size)
- continue;
- *off = paddr - d->mmio_addr;
- return d;
- }
- return NULL;
-}
-
-/* FIXME: Use vq array. */
-static struct virtqueue *vq_by_num(struct device *d, u32 num)
-{
- struct virtqueue *vq = d->vq;
-
- while (num-- && vq)
- vq = vq->next;
-
- return vq;
-}
-
-static void save_vq_config(const struct virtio_pci_common_cfg *cfg,
- struct virtqueue *vq)
-{
- vq->pci_config = *cfg;
-}
-
-static void restore_vq_config(struct virtio_pci_common_cfg *cfg,
- struct virtqueue *vq)
-{
- /* Only restore the per-vq part */
- size_t off = offsetof(struct virtio_pci_common_cfg, queue_size);
-
- memcpy((void *)cfg + off, (void *)&vq->pci_config + off,
- sizeof(*cfg) - off);
-}
-
-/*
- * 4.1.4.3.2:
- *
- * The driver MUST configure the other virtqueue fields before
- * enabling the virtqueue with queue_enable.
- *
- * When they enable the virtqueue, we check that their setup is valid.
- */
-static void check_virtqueue(struct device *d, struct virtqueue *vq)
-{
- /* Because lguest is 32 bit, all the descriptor high bits must be 0 */
- if (vq->pci_config.queue_desc_hi
- || vq->pci_config.queue_avail_hi
- || vq->pci_config.queue_used_hi)
- bad_driver_vq(vq, "invalid 64-bit queue address");
-
- /*
- * 2.4.1:
- *
- * The driver MUST ensure that the physical address of the first byte
- * of each virtqueue part is a multiple of the specified alignment
- * value in the above table.
- */
- if (vq->pci_config.queue_desc_lo % 16
- || vq->pci_config.queue_avail_lo % 2
- || vq->pci_config.queue_used_lo % 4)
- bad_driver_vq(vq, "invalid alignment in queue addresses");
-
- /* Initialize the virtqueue and check they're all in range. */
- vq->vring.num = vq->pci_config.queue_size;
- vq->vring.desc = check_pointer(vq->dev,
- vq->pci_config.queue_desc_lo,
- sizeof(*vq->vring.desc) * vq->vring.num);
- vq->vring.avail = check_pointer(vq->dev,
- vq->pci_config.queue_avail_lo,
- sizeof(*vq->vring.avail)
- + (sizeof(vq->vring.avail->ring[0])
- * vq->vring.num));
- vq->vring.used = check_pointer(vq->dev,
- vq->pci_config.queue_used_lo,
- sizeof(*vq->vring.used)
- + (sizeof(vq->vring.used->ring[0])
- * vq->vring.num));
-
- /*
- * 2.4.9.1:
- *
- * The driver MUST initialize flags in the used ring to 0
- * when allocating the used ring.
- */
- if (vq->vring.used->flags != 0)
- bad_driver_vq(vq, "invalid initial used.flags %#x",
- vq->vring.used->flags);
-}
-
-static void start_virtqueue(struct virtqueue *vq)
-{
- /*
- * Create stack for thread. Since the stack grows upwards, we point
- * the stack pointer to the end of this region.
- */
- char *stack = malloc(32768);
-
- /* Create a zero-initialized eventfd. */
- vq->eventfd = eventfd(0, 0);
- if (vq->eventfd < 0)
- err(1, "Creating eventfd");
-
- /*
- * CLONE_VM: because it has to access the Guest memory, and SIGCHLD so
- * we get a signal if it dies.
- */
- vq->thread = clone(do_thread, stack + 32768, CLONE_VM | SIGCHLD, vq);
- if (vq->thread == (pid_t)-1)
- err(1, "Creating clone");
-}
-
-static void start_virtqueues(struct device *d)
-{
- struct virtqueue *vq;
-
- for (vq = d->vq; vq; vq = vq->next) {
- if (vq->pci_config.queue_enable)
- start_virtqueue(vq);
- }
-}
-
-static void emulate_mmio_write(struct device *d, u32 off, u32 val, u32 mask)
-{
- struct virtqueue *vq;
-
- switch (off) {
- case offsetof(struct virtio_pci_mmio, cfg.device_feature_select):
- /*
- * 4.1.4.3.1:
- *
- * The device MUST present the feature bits it is offering in
- * device_feature, starting at bit device_feature_select ∗ 32
- * for any device_feature_select written by the driver
- */
- if (val == 0)
- d->mmio->cfg.device_feature = d->features;
- else if (val == 1)
- d->mmio->cfg.device_feature = (d->features >> 32);
- else
- d->mmio->cfg.device_feature = 0;
- goto feature_write_through32;
- case offsetof(struct virtio_pci_mmio, cfg.guest_feature_select):
- if (val > 1)
- bad_driver(d, "Unexpected driver select %u", val);
- goto feature_write_through32;
- case offsetof(struct virtio_pci_mmio, cfg.guest_feature):
- if (d->mmio->cfg.guest_feature_select == 0) {
- d->features_accepted &= ~((u64)0xFFFFFFFF);
- d->features_accepted |= val;
- } else {
- assert(d->mmio->cfg.guest_feature_select == 1);
- d->features_accepted &= 0xFFFFFFFF;
- d->features_accepted |= ((u64)val) << 32;
- }
- /*
- * 2.2.1:
- *
- * The driver MUST NOT accept a feature which the device did
- * not offer
- */
- if (d->features_accepted & ~d->features)
- bad_driver(d, "over-accepted features %#llx of %#llx",
- d->features_accepted, d->features);
- goto feature_write_through32;
- case offsetof(struct virtio_pci_mmio, cfg.device_status): {
- u8 prev;
-
- verbose("%s: device status -> %#x\n", d->name, val);
- /*
- * 4.1.4.3.1:
- *
- * The device MUST reset when 0 is written to device_status,
- * and present a 0 in device_status once that is done.
- */
- if (val == 0) {
- reset_device(d);
- goto write_through8;
- }
-
- /* 2.1.1: The driver MUST NOT clear a device status bit. */
- if (d->mmio->cfg.device_status & ~val)
- bad_driver(d, "unset of device status bit %#x -> %#x",
- d->mmio->cfg.device_status, val);
-
- /*
- * 2.1.2:
- *
- * The device MUST NOT consume buffers or notify the driver
- * before DRIVER_OK.
- */
- if (val & VIRTIO_CONFIG_S_DRIVER_OK
- && !(d->mmio->cfg.device_status & VIRTIO_CONFIG_S_DRIVER_OK))
- start_virtqueues(d);
-
- /*
- * 3.1.1:
- *
- * The driver MUST follow this sequence to initialize a device:
- * - Reset the device.
- * - Set the ACKNOWLEDGE status bit: the guest OS has
- * notice the device.
- * - Set the DRIVER status bit: the guest OS knows how
- * to drive the device.
- * - Read device feature bits, and write the subset
- * of feature bits understood by the OS and driver
- * to the device. During this step the driver MAY
- * read (but MUST NOT write) the device-specific
- * configuration fields to check that it can
- * support the device before accepting it.
- * - Set the FEATURES_OK status bit. The driver
- * MUST not accept new feature bits after this
- * step.
- * - Re-read device status to ensure the FEATURES_OK
- * bit is still set: otherwise, the device does
- * not support our subset of features and the
- * device is unusable.
- * - Perform device-specific setup, including
- * discovery of virtqueues for the device,
- * optional per-bus setup, reading and possibly
- * writing the device’s virtio configuration
- * space, and population of virtqueues.
- * - Set the DRIVER_OK status bit. At this point the
- * device is “live”.
- */
- prev = 0;
- switch (val & ~d->mmio->cfg.device_status) {
- case VIRTIO_CONFIG_S_DRIVER_OK:
- prev |= VIRTIO_CONFIG_S_FEATURES_OK; /* fall thru */
- case VIRTIO_CONFIG_S_FEATURES_OK:
- prev |= VIRTIO_CONFIG_S_DRIVER; /* fall thru */
- case VIRTIO_CONFIG_S_DRIVER:
- prev |= VIRTIO_CONFIG_S_ACKNOWLEDGE; /* fall thru */
- case VIRTIO_CONFIG_S_ACKNOWLEDGE:
- break;
- default:
- bad_driver(d, "unknown device status bit %#x -> %#x",
- d->mmio->cfg.device_status, val);
- }
- if (d->mmio->cfg.device_status != prev)
- bad_driver(d, "unexpected status transition %#x -> %#x",
- d->mmio->cfg.device_status, val);
-
- /* If they just wrote FEATURES_OK, we make sure they read */
- switch (val & ~d->mmio->cfg.device_status) {
- case VIRTIO_CONFIG_S_FEATURES_OK:
- d->wrote_features_ok = true;
- break;
- case VIRTIO_CONFIG_S_DRIVER_OK:
- if (d->wrote_features_ok)
- bad_driver(d, "did not re-read FEATURES_OK");
- break;
- }
- goto write_through8;
- }
- case offsetof(struct virtio_pci_mmio, cfg.queue_select):
- vq = vq_by_num(d, val);
- /*
- * 4.1.4.3.1:
- *
- * The device MUST present a 0 in queue_size if the virtqueue
- * corresponding to the current queue_select is unavailable.
- */
- if (!vq) {
- d->mmio->cfg.queue_size = 0;
- goto write_through16;
- }
- /* Save registers for old vq, if it was a valid vq */
- if (d->mmio->cfg.queue_size)
- save_vq_config(&d->mmio->cfg,
- vq_by_num(d, d->mmio->cfg.queue_select));
- /* Restore the registers for the queue they asked for */
- restore_vq_config(&d->mmio->cfg, vq);
- goto write_through16;
- case offsetof(struct virtio_pci_mmio, cfg.queue_size):
- /*
- * 4.1.4.3.2:
- *
- * The driver MUST NOT write a value which is not a power of 2
- * to queue_size.
- */
- if (val & (val-1))
- bad_driver(d, "invalid queue size %u", val);
- if (d->mmio->cfg.queue_enable)
- bad_driver(d, "changing queue size on live device");
- goto write_through16;
- case offsetof(struct virtio_pci_mmio, cfg.queue_msix_vector):
- bad_driver(d, "attempt to set MSIX vector to %u", val);
- case offsetof(struct virtio_pci_mmio, cfg.queue_enable): {
- struct virtqueue *vq = vq_by_num(d, d->mmio->cfg.queue_select);
-
- /*
- * 4.1.4.3.2:
- *
- * The driver MUST NOT write a 0 to queue_enable.
- */
- if (val != 1)
- bad_driver(d, "setting queue_enable to %u", val);
-
- /*
- * 3.1.1:
- *
- * 7. Perform device-specific setup, including discovery of
- * virtqueues for the device, optional per-bus setup,
- * reading and possibly writing the device’s virtio
- * configuration space, and population of virtqueues.
- * 8. Set the DRIVER_OK status bit.
- *
- * All our devices require all virtqueues to be enabled, so
- * they should have done that before setting DRIVER_OK.
- */
- if (d->mmio->cfg.device_status & VIRTIO_CONFIG_S_DRIVER_OK)
- bad_driver(d, "enabling vq after DRIVER_OK");
-
- d->mmio->cfg.queue_enable = val;
- save_vq_config(&d->mmio->cfg, vq);
- check_virtqueue(d, vq);
- goto write_through16;
- }
- case offsetof(struct virtio_pci_mmio, cfg.queue_notify_off):
- bad_driver(d, "attempt to write to queue_notify_off");
- case offsetof(struct virtio_pci_mmio, cfg.queue_desc_lo):
- case offsetof(struct virtio_pci_mmio, cfg.queue_desc_hi):
- case offsetof(struct virtio_pci_mmio, cfg.queue_avail_lo):
- case offsetof(struct virtio_pci_mmio, cfg.queue_avail_hi):
- case offsetof(struct virtio_pci_mmio, cfg.queue_used_lo):
- case offsetof(struct virtio_pci_mmio, cfg.queue_used_hi):
- /*
- * 4.1.4.3.2:
- *
- * The driver MUST configure the other virtqueue fields before
- * enabling the virtqueue with queue_enable.
- */
- if (d->mmio->cfg.queue_enable)
- bad_driver(d, "changing queue on live device");
-
- /*
- * 3.1.1:
- *
- * The driver MUST follow this sequence to initialize a device:
- *...
- * 5. Set the FEATURES_OK status bit. The driver MUST not
- * accept new feature bits after this step.
- */
- if (!(d->mmio->cfg.device_status & VIRTIO_CONFIG_S_FEATURES_OK))
- bad_driver(d, "setting up vq before FEATURES_OK");
-
- /*
- * 6. Re-read device status to ensure the FEATURES_OK bit is
- * still set...
- */
- if (d->wrote_features_ok)
- bad_driver(d, "didn't re-read FEATURES_OK before setup");
-
- goto write_through32;
- case offsetof(struct virtio_pci_mmio, notify):
- vq = vq_by_num(d, val);
- if (!vq)
- bad_driver(d, "Invalid vq notification on %u", val);
- /* Notify the process handling this vq by adding 1 to eventfd */
- write(vq->eventfd, "\1\0\0\0\0\0\0\0", 8);
- goto write_through16;
- case offsetof(struct virtio_pci_mmio, isr):
- bad_driver(d, "Unexpected write to isr");
- /* Weird corner case: write to emerg_wr of console */
- case sizeof(struct virtio_pci_mmio)
- + offsetof(struct virtio_console_config, emerg_wr):
- if (strcmp(d->name, "console") == 0) {
- char c = val;
- write(STDOUT_FILENO, &c, 1);
- goto write_through32;
- }
- /* Fall through... */
- default:
- /*
- * 4.1.4.3.2:
- *
- * The driver MUST NOT write to device_feature, num_queues,
- * config_generation or queue_notify_off.
- */
- bad_driver(d, "Unexpected write to offset %u", off);
- }
-
-feature_write_through32:
- /*
- * 3.1.1:
- *
- * The driver MUST follow this sequence to initialize a device:
- *...
- * - Set the DRIVER status bit: the guest OS knows how
- * to drive the device.
- * - Read device feature bits, and write the subset
- * of feature bits understood by the OS and driver
- * to the device.
- *...
- * - Set the FEATURES_OK status bit. The driver MUST not
- * accept new feature bits after this step.
- */
- if (!(d->mmio->cfg.device_status & VIRTIO_CONFIG_S_DRIVER))
- bad_driver(d, "feature write before VIRTIO_CONFIG_S_DRIVER");
- if (d->mmio->cfg.device_status & VIRTIO_CONFIG_S_FEATURES_OK)
- bad_driver(d, "feature write after VIRTIO_CONFIG_S_FEATURES_OK");
-
- /*
- * 4.1.3.1:
- *
- * The driver MUST access each field using the “natural” access
- * method, i.e. 32-bit accesses for 32-bit fields, 16-bit accesses for
- * 16-bit fields and 8-bit accesses for 8-bit fields.
- */
-write_through32:
- if (mask != 0xFFFFFFFF) {
- bad_driver(d, "non-32-bit write to offset %u (%#x)",
- off, getreg(eip));
- return;
- }
- memcpy((char *)d->mmio + off, &val, 4);
- return;
-
-write_through16:
- if (mask != 0xFFFF)
- bad_driver(d, "non-16-bit write to offset %u (%#x)",
- off, getreg(eip));
- memcpy((char *)d->mmio + off, &val, 2);
- return;
-
-write_through8:
- if (mask != 0xFF)
- bad_driver(d, "non-8-bit write to offset %u (%#x)",
- off, getreg(eip));
- memcpy((char *)d->mmio + off, &val, 1);
- return;
-}
-
-static u32 emulate_mmio_read(struct device *d, u32 off, u32 mask)
-{
- u8 isr;
- u32 val = 0;
-
- switch (off) {
- case offsetof(struct virtio_pci_mmio, cfg.device_feature_select):
- case offsetof(struct virtio_pci_mmio, cfg.device_feature):
- case offsetof(struct virtio_pci_mmio, cfg.guest_feature_select):
- case offsetof(struct virtio_pci_mmio, cfg.guest_feature):
- /*
- * 3.1.1:
- *
- * The driver MUST follow this sequence to initialize a device:
- *...
- * - Set the DRIVER status bit: the guest OS knows how
- * to drive the device.
- * - Read device feature bits, and write the subset
- * of feature bits understood by the OS and driver
- * to the device.
- */
- if (!(d->mmio->cfg.device_status & VIRTIO_CONFIG_S_DRIVER))
- bad_driver(d,
- "feature read before VIRTIO_CONFIG_S_DRIVER");
- goto read_through32;
- case offsetof(struct virtio_pci_mmio, cfg.msix_config):
- bad_driver(d, "read of msix_config");
- case offsetof(struct virtio_pci_mmio, cfg.num_queues):
- goto read_through16;
- case offsetof(struct virtio_pci_mmio, cfg.device_status):
- /* As they did read, any write of FEATURES_OK is now fine. */
- d->wrote_features_ok = false;
- goto read_through8;
- case offsetof(struct virtio_pci_mmio, cfg.config_generation):
- /*
- * 4.1.4.3.1:
- *
- * The device MUST present a changed config_generation after
- * the driver has read a device-specific configuration value
- * which has changed since any part of the device-specific
- * configuration was last read.
- *
- * This is simple: none of our devices change config, so this
- * is always 0.
- */
- goto read_through8;
- case offsetof(struct virtio_pci_mmio, notify):
- /*
- * 3.1.1:
- *
- * The driver MUST NOT notify the device before setting
- * DRIVER_OK.
- */
- if (!(d->mmio->cfg.device_status & VIRTIO_CONFIG_S_DRIVER_OK))
- bad_driver(d, "notify before VIRTIO_CONFIG_S_DRIVER_OK");
- goto read_through16;
- case offsetof(struct virtio_pci_mmio, isr):
- if (mask != 0xFF)
- bad_driver(d, "non-8-bit read from offset %u (%#x)",
- off, getreg(eip));
- isr = d->mmio->isr;
- /*
- * 4.1.4.5.1:
- *
- * The device MUST reset ISR status to 0 on driver read.
- */
- d->mmio->isr = 0;
- return isr;
- case offsetof(struct virtio_pci_mmio, padding):
- bad_driver(d, "read from padding (%#x)", getreg(eip));
- default:
- /* Read from device config space, beware unaligned overflow */
- if (off > d->mmio_size - 4)
- bad_driver(d, "read past end (%#x)", getreg(eip));
-
- /*
- * 3.1.1:
- * The driver MUST follow this sequence to initialize a device:
- *...
- * 3. Set the DRIVER status bit: the guest OS knows how to
- * drive the device.
- * 4. Read device feature bits, and write the subset of
- * feature bits understood by the OS and driver to the
- * device. During this step the driver MAY read (but MUST NOT
- * write) the device-specific configuration fields to check
- * that it can support the device before accepting it.
- */
- if (!(d->mmio->cfg.device_status & VIRTIO_CONFIG_S_DRIVER))
- bad_driver(d,
- "config read before VIRTIO_CONFIG_S_DRIVER");
-
- if (mask == 0xFFFFFFFF)
- goto read_through32;
- else if (mask == 0xFFFF)
- goto read_through16;
- else
- goto read_through8;
- }
-
- /*
- * 4.1.3.1:
- *
- * The driver MUST access each field using the “natural” access
- * method, i.e. 32-bit accesses for 32-bit fields, 16-bit accesses for
- * 16-bit fields and 8-bit accesses for 8-bit fields.
- */
-read_through32:
- if (mask != 0xFFFFFFFF)
- bad_driver(d, "non-32-bit read to offset %u (%#x)",
- off, getreg(eip));
- memcpy(&val, (char *)d->mmio + off, 4);
- return val;
-
-read_through16:
- if (mask != 0xFFFF)
- bad_driver(d, "non-16-bit read to offset %u (%#x)",
- off, getreg(eip));
- memcpy(&val, (char *)d->mmio + off, 2);
- return val;
-
-read_through8:
- if (mask != 0xFF)
- bad_driver(d, "non-8-bit read to offset %u (%#x)",
- off, getreg(eip));
- memcpy(&val, (char *)d->mmio + off, 1);
- return val;
-}
-
-static void emulate_mmio(unsigned long paddr, const u8 *insn)
-{
- u32 val, off, mask = 0xFFFFFFFF, insnlen = 0;
- struct device *d = find_mmio_region(paddr, &off);
- unsigned long args[] = { LHREQ_TRAP, 14 };
-
- if (!d) {
- warnx("MMIO touching %#08lx (not a device)", paddr);
- goto reinject;
- }
-
- /* Prefix makes it a 16 bit op */
- if (insn[0] == 0x66) {
- mask = 0xFFFF;
- insnlen++;
- }
-
- /* iowrite */
- if (insn[insnlen] == 0x89) {
- /* Next byte is r/m byte: bits 3-5 are register. */
- val = getreg_num((insn[insnlen+1] >> 3) & 0x7, mask);
- emulate_mmio_write(d, off, val, mask);
- insnlen += 2 + insn_displacement_len(insn[insnlen+1]);
- } else if (insn[insnlen] == 0x8b) { /* ioread */
- /* Next byte is r/m byte: bits 3-5 are register. */
- val = emulate_mmio_read(d, off, mask);
- setreg_num((insn[insnlen+1] >> 3) & 0x7, val, mask);
- insnlen += 2 + insn_displacement_len(insn[insnlen+1]);
- } else if (insn[0] == 0x88) { /* 8-bit iowrite */
- mask = 0xff;
- /* Next byte is r/m byte: bits 3-5 are register. */
- val = getreg_num((insn[1] >> 3) & 0x7, mask);
- emulate_mmio_write(d, off, val, mask);
- insnlen = 2 + insn_displacement_len(insn[1]);
- } else if (insn[0] == 0x8a) { /* 8-bit ioread */
- mask = 0xff;
- val = emulate_mmio_read(d, off, mask);
- setreg_num((insn[1] >> 3) & 0x7, val, mask);
- insnlen = 2 + insn_displacement_len(insn[1]);
- } else {
- warnx("Unknown MMIO instruction touching %#08lx:"
- " %02x %02x %02x %02x at %u",
- paddr, insn[0], insn[1], insn[2], insn[3], getreg(eip));
- reinject:
- /* Inject trap into Guest. */
- if (write(lguest_fd, args, sizeof(args)) < 0)
- err(1, "Reinjecting trap 14 for fault at %#x",
- getreg(eip));
- return;
- }
-
- /* Finally, we've "done" the instruction, so move past it. */
- setreg(eip, getreg(eip) + insnlen);
-}
-
-/*L:190
- * Device Setup
- *
- * All devices need a descriptor so the Guest knows it exists, and a "struct
- * device" so the Launcher can keep track of it. We have common helper
- * routines to allocate and manage them.
- */
-static void add_pci_virtqueue(struct device *dev,
- void (*service)(struct virtqueue *),
- const char *name)
-{
- struct virtqueue **i, *vq = malloc(sizeof(*vq));
-
- /* Initialize the virtqueue */
- vq->next = NULL;
- vq->last_avail_idx = 0;
- vq->dev = dev;
- vq->name = name;
-
- /*
- * This is the routine the service thread will run, and its Process ID
- * once it's running.
- */
- vq->service = service;
- vq->thread = (pid_t)-1;
-
- /* Initialize the configuration. */
- reset_vq_pci_config(vq);
- vq->pci_config.queue_notify_off = 0;
-
- /* Add one to the number of queues */
- vq->dev->mmio->cfg.num_queues++;
-
- /*
- * Add to tail of list, so dev->vq is first vq, dev->vq->next is
- * second.
- */
- for (i = &dev->vq; *i; i = &(*i)->next);
- *i = vq;
-}
-
-/* The Guest accesses the feature bits via the PCI common config MMIO region */
-static void add_pci_feature(struct device *dev, unsigned bit)
-{
- dev->features |= (1ULL << bit);
-}
-
-/* For devices with no config. */
-static void no_device_config(struct device *dev)
-{
- dev->mmio_addr = get_mmio_region(dev->mmio_size);
-
- dev->config.bar[0] = dev->mmio_addr;
- /* Bottom 4 bits must be zero */
- assert(~(dev->config.bar[0] & 0xF));
-}
-
-/* This puts the device config into BAR0 */
-static void set_device_config(struct device *dev, const void *conf, size_t len)
-{
- /* Set up BAR 0 */
- dev->mmio_size += len;
- dev->mmio = realloc(dev->mmio, dev->mmio_size);
- memcpy(dev->mmio + 1, conf, len);
-
- /*
- * 4.1.4.6:
- *
- * The device MUST present at least one VIRTIO_PCI_CAP_DEVICE_CFG
- * capability for any device type which has a device-specific
- * configuration.
- */
- /* Hook up device cfg */
- dev->config.cfg_access.cap.cap_next
- = offsetof(struct pci_config, device);
-
- /*
- * 4.1.4.6.1:
- *
- * The offset for the device-specific configuration MUST be 4-byte
- * aligned.
- */
- assert(dev->config.cfg_access.cap.cap_next % 4 == 0);
-
- /* Fix up device cfg field length. */
- dev->config.device.length = len;
-
- /* The rest is the same as the no-config case */
- no_device_config(dev);
-}
-
-static void init_cap(struct virtio_pci_cap *cap, size_t caplen, int type,
- size_t bar_offset, size_t bar_bytes, u8 next)
-{
- cap->cap_vndr = PCI_CAP_ID_VNDR;
- cap->cap_next = next;
- cap->cap_len = caplen;
- cap->cfg_type = type;
- cap->bar = 0;
- memset(cap->padding, 0, sizeof(cap->padding));
- cap->offset = bar_offset;
- cap->length = bar_bytes;
-}
-
-/*
- * This sets up the pci_config structure, as defined in the virtio 1.0
- * standard (and PCI standard).
- */
-static void init_pci_config(struct pci_config *pci, u16 type,
- u8 class, u8 subclass)
-{
- size_t bar_offset, bar_len;
-
- /*
- * 4.1.4.4.1:
- *
- * The device MUST either present notify_off_multiplier as an even
- * power of 2, or present notify_off_multiplier as 0.
- *
- * 2.1.2:
- *
- * The device MUST initialize device status to 0 upon reset.
- */
- memset(pci, 0, sizeof(*pci));
-
- /* 4.1.2.1: Devices MUST have the PCI Vendor ID 0x1AF4 */
- pci->vendor_id = 0x1AF4;
- /* 4.1.2.1: ... PCI Device ID calculated by adding 0x1040 ... */
- pci->device_id = 0x1040 + type;
-
- /*
- * PCI have specific codes for different types of devices.
- * Linux doesn't care, but it's a good clue for people looking
- * at the device.
- */
- pci->class = class;
- pci->subclass = subclass;
-
- /*
- * 4.1.2.1:
- *
- * Non-transitional devices SHOULD have a PCI Revision ID of 1 or
- * higher
- */
- pci->revid = 1;
-
- /*
- * 4.1.2.1:
- *
- * Non-transitional devices SHOULD have a PCI Subsystem Device ID of
- * 0x40 or higher.
- */
- pci->subsystem_device_id = 0x40;
-
- /* We use our dummy interrupt controller, and irq_line is the irq */
- pci->irq_line = devices.next_irq++;
- pci->irq_pin = 0;
-
- /* Support for extended capabilities. */
- pci->status = (1 << 4);
-
- /* Link them in. */
- /*
- * 4.1.4.3.1:
- *
- * The device MUST present at least one common configuration
- * capability.
- */
- pci->capabilities = offsetof(struct pci_config, common);
-
- /* 4.1.4.3.1 ... offset MUST be 4-byte aligned. */
- assert(pci->capabilities % 4 == 0);
-
- bar_offset = offsetof(struct virtio_pci_mmio, cfg);
- bar_len = sizeof(((struct virtio_pci_mmio *)0)->cfg);
- init_cap(&pci->common, sizeof(pci->common), VIRTIO_PCI_CAP_COMMON_CFG,
- bar_offset, bar_len,
- offsetof(struct pci_config, notify));
-
- /*
- * 4.1.4.4.1:
- *
- * The device MUST present at least one notification capability.
- */
- bar_offset += bar_len;
- bar_len = sizeof(((struct virtio_pci_mmio *)0)->notify);
-
- /*
- * 4.1.4.4.1:
- *
- * The cap.offset MUST be 2-byte aligned.
- */
- assert(pci->common.cap_next % 2 == 0);
-
- /* FIXME: Use a non-zero notify_off, for per-queue notification? */
- /*
- * 4.1.4.4.1:
- *
- * The value cap.length presented by the device MUST be at least 2 and
- * MUST be large enough to support queue notification offsets for all
- * supported queues in all possible configurations.
- */
- assert(bar_len >= 2);
-
- init_cap(&pci->notify.cap, sizeof(pci->notify),
- VIRTIO_PCI_CAP_NOTIFY_CFG,
- bar_offset, bar_len,
- offsetof(struct pci_config, isr));
-
- bar_offset += bar_len;
- bar_len = sizeof(((struct virtio_pci_mmio *)0)->isr);
- /*
- * 4.1.4.5.1:
- *
- * The device MUST present at least one VIRTIO_PCI_CAP_ISR_CFG
- * capability.
- */
- init_cap(&pci->isr, sizeof(pci->isr),
- VIRTIO_PCI_CAP_ISR_CFG,
- bar_offset, bar_len,
- offsetof(struct pci_config, cfg_access));
-
- /*
- * 4.1.4.7.1:
- *
- * The device MUST present at least one VIRTIO_PCI_CAP_PCI_CFG
- * capability.
- */
- /* This doesn't have any presence in the BAR */
- init_cap(&pci->cfg_access.cap, sizeof(pci->cfg_access),
- VIRTIO_PCI_CAP_PCI_CFG,
- 0, 0, 0);
-
- bar_offset += bar_len + sizeof(((struct virtio_pci_mmio *)0)->padding);
- assert(bar_offset == sizeof(struct virtio_pci_mmio));
-
- /*
- * This gets sewn in and length set in set_device_config().
- * Some devices don't have a device configuration interface, so
- * we never expose this if we don't call set_device_config().
- */
- init_cap(&pci->device, sizeof(pci->device), VIRTIO_PCI_CAP_DEVICE_CFG,
- bar_offset, 0, 0);
-}
-
-/*
- * This routine does all the creation and setup of a new device, but we don't
- * actually place the MMIO region until we know the size (if any) of the
- * device-specific config. And we don't actually start the service threads
- * until later.
- *
- * See what I mean about userspace being boring?
- */
-static struct device *new_pci_device(const char *name, u16 type,
- u8 class, u8 subclass)
-{
- struct device *dev = malloc(sizeof(*dev));
-
- /* Now we populate the fields one at a time. */
- dev->name = name;
- dev->vq = NULL;
- dev->running = false;
- dev->wrote_features_ok = false;
- dev->mmio_size = sizeof(struct virtio_pci_mmio);
- dev->mmio = calloc(1, dev->mmio_size);
- dev->features = (u64)1 << VIRTIO_F_VERSION_1;
- dev->features_accepted = 0;
-
- if (devices.device_num + 1 >= MAX_PCI_DEVICES)
- errx(1, "Can only handle 31 PCI devices");
-
- init_pci_config(&dev->config, type, class, subclass);
- assert(!devices.pci[devices.device_num+1]);
- devices.pci[++devices.device_num] = dev;
-
- return dev;
-}
-
-/*
- * Our first setup routine is the console. It's a fairly simple device, but
- * UNIX tty handling makes it uglier than it could be.
- */
-static void setup_console(void)
-{
- struct device *dev;
- struct virtio_console_config conf;
-
- /* If we can save the initial standard input settings... */
- if (tcgetattr(STDIN_FILENO, &orig_term) == 0) {
- struct termios term = orig_term;
- /*
- * Then we turn off echo, line buffering and ^C etc: We want a
- * raw input stream to the Guest.
- */
- term.c_lflag &= ~(ISIG|ICANON|ECHO);
- tcsetattr(STDIN_FILENO, TCSANOW, &term);
- }
-
- dev = new_pci_device("console", VIRTIO_ID_CONSOLE, 0x07, 0x00);
-
- /* We store the console state in dev->priv, and initialize it. */
- dev->priv = malloc(sizeof(struct console_abort));
- ((struct console_abort *)dev->priv)->count = 0;
-
- /*
- * The console needs two virtqueues: the input then the output. When
- * they put something the input queue, we make sure we're listening to
- * stdin. When they put something in the output queue, we write it to
- * stdout.
- */
- add_pci_virtqueue(dev, console_input, "input");
- add_pci_virtqueue(dev, console_output, "output");
-
- /* We need a configuration area for the emerg_wr early writes. */
- add_pci_feature(dev, VIRTIO_CONSOLE_F_EMERG_WRITE);
- set_device_config(dev, &conf, sizeof(conf));
-
- verbose("device %u: console\n", devices.device_num);
-}
-/*:*/
-
-/*M:010
- * Inter-guest networking is an interesting area. Simplest is to have a
- * --sharenet=<name> option which opens or creates a named pipe. This can be
- * used to send packets to another guest in a 1:1 manner.
- *
- * More sophisticated is to use one of the tools developed for project like UML
- * to do networking.
- *
- * Faster is to do virtio bonding in kernel. Doing this 1:1 would be
- * completely generic ("here's my vring, attach to your vring") and would work
- * for any traffic. Of course, namespace and permissions issues need to be
- * dealt with. A more sophisticated "multi-channel" virtio_net.c could hide
- * multiple inter-guest channels behind one interface, although it would
- * require some manner of hotplugging new virtio channels.
- *
- * Finally, we could use a virtio network switch in the kernel, ie. vhost.
-:*/
-
-static u32 str2ip(const char *ipaddr)
-{
- unsigned int b[4];
-
- if (sscanf(ipaddr, "%u.%u.%u.%u", &b[0], &b[1], &b[2], &b[3]) != 4)
- errx(1, "Failed to parse IP address '%s'", ipaddr);
- return (b[0] << 24) | (b[1] << 16) | (b[2] << 8) | b[3];
-}
-
-static void str2mac(const char *macaddr, unsigned char mac[6])
-{
- unsigned int m[6];
- if (sscanf(macaddr, "%02x:%02x:%02x:%02x:%02x:%02x",
- &m[0], &m[1], &m[2], &m[3], &m[4], &m[5]) != 6)
- errx(1, "Failed to parse mac address '%s'", macaddr);
- mac[0] = m[0];
- mac[1] = m[1];
- mac[2] = m[2];
- mac[3] = m[3];
- mac[4] = m[4];
- mac[5] = m[5];
-}
-
-/*
- * This code is "adapted" from libbridge: it attaches the Host end of the
- * network device to the bridge device specified by the command line.
- *
- * This is yet another James Morris contribution (I'm an IP-level guy, so I
- * dislike bridging), and I just try not to break it.
- */
-static void add_to_bridge(int fd, const char *if_name, const char *br_name)
-{
- int ifidx;
- struct ifreq ifr;
-
- if (!*br_name)
- errx(1, "must specify bridge name");
-
- ifidx = if_nametoindex(if_name);
- if (!ifidx)
- errx(1, "interface %s does not exist!", if_name);
-
- strncpy(ifr.ifr_name, br_name, IFNAMSIZ);
- ifr.ifr_name[IFNAMSIZ-1] = '\0';
- ifr.ifr_ifindex = ifidx;
- if (ioctl(fd, SIOCBRADDIF, &ifr) < 0)
- err(1, "can't add %s to bridge %s", if_name, br_name);
-}
-
-/*
- * This sets up the Host end of the network device with an IP address, brings
- * it up so packets will flow, the copies the MAC address into the hwaddr
- * pointer.
- */
-static void configure_device(int fd, const char *tapif, u32 ipaddr)
-{
- struct ifreq ifr;
- struct sockaddr_in sin;
-
- memset(&ifr, 0, sizeof(ifr));
- strcpy(ifr.ifr_name, tapif);
-
- /* Don't read these incantations. Just cut & paste them like I did! */
- sin.sin_family = AF_INET;
- sin.sin_addr.s_addr = htonl(ipaddr);
- memcpy(&ifr.ifr_addr, &sin, sizeof(sin));
- if (ioctl(fd, SIOCSIFADDR, &ifr) != 0)
- err(1, "Setting %s interface address", tapif);
- ifr.ifr_flags = IFF_UP;
- if (ioctl(fd, SIOCSIFFLAGS, &ifr) != 0)
- err(1, "Bringing interface %s up", tapif);
-}
-
-static int get_tun_device(char tapif[IFNAMSIZ])
-{
- struct ifreq ifr;
- int vnet_hdr_sz;
- int netfd;
-
- /* Start with this zeroed. Messy but sure. */
- memset(&ifr, 0, sizeof(ifr));
-
- /*
- * We open the /dev/net/tun device and tell it we want a tap device. A
- * tap device is like a tun device, only somehow different. To tell
- * the truth, I completely blundered my way through this code, but it
- * works now!
- */
- netfd = open_or_die("/dev/net/tun", O_RDWR);
- ifr.ifr_flags = IFF_TAP | IFF_NO_PI | IFF_VNET_HDR;
- strcpy(ifr.ifr_name, "tap%d");
- if (ioctl(netfd, TUNSETIFF, &ifr) != 0)
- err(1, "configuring /dev/net/tun");
-
- if (ioctl(netfd, TUNSETOFFLOAD,
- TUN_F_CSUM|TUN_F_TSO4|TUN_F_TSO6|TUN_F_TSO_ECN) != 0)
- err(1, "Could not set features for tun device");
-
- /*
- * We don't need checksums calculated for packets coming in this
- * device: trust us!
- */
- ioctl(netfd, TUNSETNOCSUM, 1);
-
- /*
- * In virtio before 1.0 (aka legacy virtio), we added a 16-bit
- * field at the end of the network header iff
- * VIRTIO_NET_F_MRG_RXBUF was negotiated. For virtio 1.0,
- * that became the norm, but we need to tell the tun device
- * about our expanded header (which is called
- * virtio_net_hdr_mrg_rxbuf in the legacy system).
- */
- vnet_hdr_sz = sizeof(struct virtio_net_hdr_v1);
- if (ioctl(netfd, TUNSETVNETHDRSZ, &vnet_hdr_sz) != 0)
- err(1, "Setting tun header size to %u", vnet_hdr_sz);
-
- memcpy(tapif, ifr.ifr_name, IFNAMSIZ);
- return netfd;
-}
-
-/*L:195
- * Our network is a Host<->Guest network. This can either use bridging or
- * routing, but the principle is the same: it uses the "tun" device to inject
- * packets into the Host as if they came in from a normal network card. We
- * just shunt packets between the Guest and the tun device.
- */
-static void setup_tun_net(char *arg)
-{
- struct device *dev;
- struct net_info *net_info = malloc(sizeof(*net_info));
- int ipfd;
- u32 ip = INADDR_ANY;
- bool bridging = false;
- char tapif[IFNAMSIZ], *p;
- struct virtio_net_config conf;
-
- net_info->tunfd = get_tun_device(tapif);
-
- /* First we create a new network device. */
- dev = new_pci_device("net", VIRTIO_ID_NET, 0x02, 0x00);
- dev->priv = net_info;
-
- /* Network devices need a recv and a send queue, just like console. */
- add_pci_virtqueue(dev, net_input, "rx");
- add_pci_virtqueue(dev, net_output, "tx");
-
- /*
- * We need a socket to perform the magic network ioctls to bring up the
- * tap interface, connect to the bridge etc. Any socket will do!
- */
- ipfd = socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
- if (ipfd < 0)
- err(1, "opening IP socket");
-
- /* If the command line was --tunnet=bridge:<name> do bridging. */
- if (!strncmp(BRIDGE_PFX, arg, strlen(BRIDGE_PFX))) {
- arg += strlen(BRIDGE_PFX);
- bridging = true;
- }
-
- /* A mac address may follow the bridge name or IP address */
- p = strchr(arg, ':');
- if (p) {
- str2mac(p+1, conf.mac);
- add_pci_feature(dev, VIRTIO_NET_F_MAC);
- *p = '\0';
- }
-
- /* arg is now either an IP address or a bridge name */
- if (bridging)
- add_to_bridge(ipfd, tapif, arg);
- else
- ip = str2ip(arg);
-
- /* Set up the tun device. */
- configure_device(ipfd, tapif, ip);
-
- /* Expect Guest to handle everything except UFO */
- add_pci_feature(dev, VIRTIO_NET_F_CSUM);
- add_pci_feature(dev, VIRTIO_NET_F_GUEST_CSUM);
- add_pci_feature(dev, VIRTIO_NET_F_GUEST_TSO4);
- add_pci_feature(dev, VIRTIO_NET_F_GUEST_TSO6);
- add_pci_feature(dev, VIRTIO_NET_F_GUEST_ECN);
- add_pci_feature(dev, VIRTIO_NET_F_HOST_TSO4);
- add_pci_feature(dev, VIRTIO_NET_F_HOST_TSO6);
- add_pci_feature(dev, VIRTIO_NET_F_HOST_ECN);
- /* We handle indirect ring entries */
- add_pci_feature(dev, VIRTIO_RING_F_INDIRECT_DESC);
- set_device_config(dev, &conf, sizeof(conf));
-
- /* We don't need the socket any more; setup is done. */
- close(ipfd);
-
- if (bridging)
- verbose("device %u: tun %s attached to bridge: %s\n",
- devices.device_num, tapif, arg);
- else
- verbose("device %u: tun %s: %s\n",
- devices.device_num, tapif, arg);
-}
-/*:*/
-
-/* This hangs off device->priv. */
-struct vblk_info {
- /* The size of the file. */
- off64_t len;
-
- /* The file descriptor for the file. */
- int fd;
-
-};
-
-/*L:210
- * The Disk
- *
- * The disk only has one virtqueue, so it only has one thread. It is really
- * simple: the Guest asks for a block number and we read or write that position
- * in the file.
- *
- * Before we serviced each virtqueue in a separate thread, that was unacceptably
- * slow: the Guest waits until the read is finished before running anything
- * else, even if it could have been doing useful work.
- *
- * We could have used async I/O, except it's reputed to suck so hard that
- * characters actually go missing from your code when you try to use it.
- */
-static void blk_request(struct virtqueue *vq)
-{
- struct vblk_info *vblk = vq->dev->priv;
- unsigned int head, out_num, in_num, wlen;
- int ret, i;
- u8 *in;
- struct virtio_blk_outhdr out;
- struct iovec iov[vq->vring.num];
- off64_t off;
-
- /*
- * Get the next request, where we normally wait. It triggers the
- * interrupt to acknowledge previously serviced requests (if any).
- */
- head = wait_for_vq_desc(vq, iov, &out_num, &in_num);
-
- /* Copy the output header from the front of the iov (adjusts iov) */
- iov_consume(vq->dev, iov, out_num, &out, sizeof(out));
-
- /* Find and trim end of iov input array, for our status byte. */
- in = NULL;
- for (i = out_num + in_num - 1; i >= out_num; i--) {
- if (iov[i].iov_len > 0) {
- in = iov[i].iov_base + iov[i].iov_len - 1;
- iov[i].iov_len--;
- break;
- }
- }
- if (!in)
- bad_driver_vq(vq, "Bad virtblk cmd with no room for status");
-
- /*
- * For historical reasons, block operations are expressed in 512 byte
- * "sectors".
- */
- off = out.sector * 512;
-
- if (out.type & VIRTIO_BLK_T_OUT) {
- /*
- * Write
- *
- * Move to the right location in the block file. This can fail
- * if they try to write past end.
- */
- if (lseek64(vblk->fd, off, SEEK_SET) != off)
- err(1, "Bad seek to sector %llu", out.sector);
-
- ret = writev(vblk->fd, iov, out_num);
- verbose("WRITE to sector %llu: %i\n", out.sector, ret);
-
- /*
- * Grr... Now we know how long the descriptor they sent was, we
- * make sure they didn't try to write over the end of the block
- * file (possibly extending it).
- */
- if (ret > 0 && off + ret > vblk->len) {
- /* Trim it back to the correct length */
- ftruncate64(vblk->fd, vblk->len);
- /* Die, bad Guest, die. */
- bad_driver_vq(vq, "Write past end %llu+%u", off, ret);
- }
-
- wlen = sizeof(*in);
- *in = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR);
- } else if (out.type & VIRTIO_BLK_T_FLUSH) {
- /* Flush */
- ret = fdatasync(vblk->fd);
- verbose("FLUSH fdatasync: %i\n", ret);
- wlen = sizeof(*in);
- *in = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR);
- } else {
- /*
- * Read
- *
- * Move to the right location in the block file. This can fail
- * if they try to read past end.
- */
- if (lseek64(vblk->fd, off, SEEK_SET) != off)
- err(1, "Bad seek to sector %llu", out.sector);
-
- ret = readv(vblk->fd, iov + out_num, in_num);
- if (ret >= 0) {
- wlen = sizeof(*in) + ret;
- *in = VIRTIO_BLK_S_OK;
- } else {
- wlen = sizeof(*in);
- *in = VIRTIO_BLK_S_IOERR;
- }
- }
-
- /* Finished that request. */
- add_used(vq, head, wlen);
-}
-
-/*L:198 This actually sets up a virtual block device. */
-static void setup_block_file(const char *filename)
-{
- struct device *dev;
- struct vblk_info *vblk;
- struct virtio_blk_config conf;
-
- /* Create the device. */
- dev = new_pci_device("block", VIRTIO_ID_BLOCK, 0x01, 0x80);
-
- /* The device has one virtqueue, where the Guest places requests. */
- add_pci_virtqueue(dev, blk_request, "request");
-
- /* Allocate the room for our own bookkeeping */
- vblk = dev->priv = malloc(sizeof(*vblk));
-
- /* First we open the file and store the length. */
- vblk->fd = open_or_die(filename, O_RDWR|O_LARGEFILE);
- vblk->len = lseek64(vblk->fd, 0, SEEK_END);
-
- /* Tell Guest how many sectors this device has. */
- conf.capacity = cpu_to_le64(vblk->len / 512);
-
- /*
- * Tell Guest not to put in too many descriptors at once: two are used
- * for the in and out elements.
- */
- add_pci_feature(dev, VIRTIO_BLK_F_SEG_MAX);
- conf.seg_max = cpu_to_le32(VIRTQUEUE_NUM - 2);
-
- set_device_config(dev, &conf, sizeof(struct virtio_blk_config));
-
- verbose("device %u: virtblock %llu sectors\n",
- devices.device_num, le64_to_cpu(conf.capacity));
-}
-
-/*L:211
- * Our random number generator device reads from /dev/urandom into the Guest's
- * input buffers. The usual case is that the Guest doesn't want random numbers
- * and so has no buffers although /dev/urandom is still readable, whereas
- * console is the reverse.
- *
- * The same logic applies, however.
- */
-struct rng_info {
- int rfd;
-};
-
-static void rng_input(struct virtqueue *vq)
-{
- int len;
- unsigned int head, in_num, out_num, totlen = 0;
- struct rng_info *rng_info = vq->dev->priv;
- struct iovec iov[vq->vring.num];
-
- /* First we need a buffer from the Guests's virtqueue. */
- head = wait_for_vq_desc(vq, iov, &out_num, &in_num);
- if (out_num)
- bad_driver_vq(vq, "Output buffers in rng?");
-
- /*
- * Just like the console write, we loop to cover the whole iovec.
- * In this case, short reads actually happen quite a bit.
- */
- while (!iov_empty(iov, in_num)) {
- len = readv(rng_info->rfd, iov, in_num);
- if (len <= 0)
- err(1, "Read from /dev/urandom gave %i", len);
- iov_consume(vq->dev, iov, in_num, NULL, len);
- totlen += len;
- }
-
- /* Tell the Guest about the new input. */
- add_used(vq, head, totlen);
-}
-
-/*L:199
- * This creates a "hardware" random number device for the Guest.
- */
-static void setup_rng(void)
-{
- struct device *dev;
- struct rng_info *rng_info = malloc(sizeof(*rng_info));
-
- /* Our device's private info simply contains the /dev/urandom fd. */
- rng_info->rfd = open_or_die("/dev/urandom", O_RDONLY);
-
- /* Create the new device. */
- dev = new_pci_device("rng", VIRTIO_ID_RNG, 0xff, 0);
- dev->priv = rng_info;
-
- /* The device has one virtqueue, where the Guest places inbufs. */
- add_pci_virtqueue(dev, rng_input, "input");
-
- /* We don't have any configuration space */
- no_device_config(dev);
-
- verbose("device %u: rng\n", devices.device_num);
-}
-/* That's the end of device setup. */
-
-/*L:230 Reboot is pretty easy: clean up and exec() the Launcher afresh. */
-static void __attribute__((noreturn)) restart_guest(void)
-{
- unsigned int i;
-
- /*
- * Since we don't track all open fds, we simply close everything beyond
- * stderr.
- */
- for (i = 3; i < FD_SETSIZE; i++)
- close(i);
-
- /* Reset all the devices (kills all threads). */
- cleanup_devices();
-
- execv(main_args[0], main_args);
- err(1, "Could not exec %s", main_args[0]);
-}
-
-/*L:220
- * Finally we reach the core of the Launcher which runs the Guest, serves
- * its input and output, and finally, lays it to rest.
- */
-static void __attribute__((noreturn)) run_guest(void)
-{
- for (;;) {
- struct lguest_pending notify;
- int readval;
-
- /* We read from the /dev/lguest device to run the Guest. */
- readval = pread(lguest_fd, ¬ify, sizeof(notify), cpu_id);
- if (readval == sizeof(notify)) {
- if (notify.trap == 13) {
- verbose("Emulating instruction at %#x\n",
- getreg(eip));
- emulate_insn(notify.insn);
- } else if (notify.trap == 14) {
- verbose("Emulating MMIO at %#x\n",
- getreg(eip));
- emulate_mmio(notify.addr, notify.insn);
- } else
- errx(1, "Unknown trap %i addr %#08x\n",
- notify.trap, notify.addr);
- /* ENOENT means the Guest died. Reading tells us why. */
- } else if (errno == ENOENT) {
- char reason[1024] = { 0 };
- pread(lguest_fd, reason, sizeof(reason)-1, cpu_id);
- errx(1, "%s", reason);
- /* ERESTART means that we need to reboot the guest */
- } else if (errno == ERESTART) {
- restart_guest();
- /* Anything else means a bug or incompatible change. */
- } else
- err(1, "Running guest failed");
- }
-}
-/*L:240
- * This is the end of the Launcher. The good news: we are over halfway
- * through! The bad news: the most fiendish part of the code still lies ahead
- * of us.
- *
- * Are you ready? Take a deep breath and join me in the core of the Host, in
- * "make Host".
-:*/
-
-static struct option opts[] = {
- { "verbose", 0, NULL, 'v' },
- { "tunnet", 1, NULL, 't' },
- { "block", 1, NULL, 'b' },
- { "rng", 0, NULL, 'r' },
- { "initrd", 1, NULL, 'i' },
- { "username", 1, NULL, 'u' },
- { "chroot", 1, NULL, 'c' },
- { NULL },
-};
-static void usage(void)
-{
- errx(1, "Usage: lguest [--verbose] "
- "[--tunnet=(<ipaddr>:<macaddr>|bridge:<bridgename>:<macaddr>)\n"
- "|--block=<filename>|--initrd=<filename>]...\n"
- "<mem-in-mb> vmlinux [args...]");
-}
-
-/*L:105 The main routine is where the real work begins: */
-int main(int argc, char *argv[])
-{
- /* Memory, code startpoint and size of the (optional) initrd. */
- unsigned long mem = 0, start, initrd_size = 0;
- /* Two temporaries. */
- int i, c;
- /* The boot information for the Guest. */
- struct boot_params *boot;
- /* If they specify an initrd file to load. */
- const char *initrd_name = NULL;
-
- /* Password structure for initgroups/setres[gu]id */
- struct passwd *user_details = NULL;
-
- /* Directory to chroot to */
- char *chroot_path = NULL;
-
- /* Save the args: we "reboot" by execing ourselves again. */
- main_args = argv;
-
- /*
- * First we initialize the device list. We remember next interrupt
- * number to use for devices (1: remember that 0 is used by the timer).
- */
- devices.next_irq = 1;
-
- /* We're CPU 0. In fact, that's the only CPU possible right now. */
- cpu_id = 0;
-
- /*
- * We need to know how much memory so we can set up the device
- * descriptor and memory pages for the devices as we parse the command
- * line. So we quickly look through the arguments to find the amount
- * of memory now.
- */
- for (i = 1; i < argc; i++) {
- if (argv[i][0] != '-') {
- mem = atoi(argv[i]) * 1024 * 1024;
- /*
- * We start by mapping anonymous pages over all of
- * guest-physical memory range. This fills it with 0,
- * and ensures that the Guest won't be killed when it
- * tries to access it.
- */
- guest_base = map_zeroed_pages(mem / getpagesize()
- + DEVICE_PAGES);
- guest_limit = mem;
- guest_max = guest_mmio = mem + DEVICE_PAGES*getpagesize();
- break;
- }
- }
-
- /* If we exit via err(), this kills all the threads, restores tty. */
- atexit(cleanup_devices);
-
- /* We always have a console device, and it's always device 1. */
- setup_console();
-
- /* The options are fairly straight-forward */
- while ((c = getopt_long(argc, argv, "v", opts, NULL)) != EOF) {
- switch (c) {
- case 'v':
- verbose = true;
- break;
- case 't':
- setup_tun_net(optarg);
- break;
- case 'b':
- setup_block_file(optarg);
- break;
- case 'r':
- setup_rng();
- break;
- case 'i':
- initrd_name = optarg;
- break;
- case 'u':
- user_details = getpwnam(optarg);
- if (!user_details)
- err(1, "getpwnam failed, incorrect username?");
- break;
- case 'c':
- chroot_path = optarg;
- break;
- default:
- warnx("Unknown argument %s", argv[optind]);
- usage();
- }
- }
- /*
- * After the other arguments we expect memory and kernel image name,
- * followed by command line arguments for the kernel.
- */
- if (optind + 2 > argc)
- usage();
-
- verbose("Guest base is at %p\n", guest_base);
-
- /* Initialize the (fake) PCI host bridge device. */
- init_pci_host_bridge();
-
- /* Now we load the kernel */
- start = load_kernel(open_or_die(argv[optind+1], O_RDONLY));
-
- /* Boot information is stashed at physical address 0 */
- boot = from_guest_phys(0);
-
- /* Map the initrd image if requested (at top of physical memory) */
- if (initrd_name) {
- initrd_size = load_initrd(initrd_name, mem);
- /*
- * These are the location in the Linux boot header where the
- * start and size of the initrd are expected to be found.
- */
- boot->hdr.ramdisk_image = mem - initrd_size;
- boot->hdr.ramdisk_size = initrd_size;
- /* The bootloader type 0xFF means "unknown"; that's OK. */
- boot->hdr.type_of_loader = 0xFF;
- }
-
- /*
- * The Linux boot header contains an "E820" memory map: ours is a
- * simple, single region.
- */
- boot->e820_entries = 1;
- boot->e820_table[0] = ((struct e820_entry) { 0, mem, E820_TYPE_RAM });
- /*
- * The boot header contains a command line pointer: we put the command
- * line after the boot header.
- */
- boot->hdr.cmd_line_ptr = to_guest_phys(boot + 1);
- /* We use a simple helper to copy the arguments separated by spaces. */
- concat((char *)(boot + 1), argv+optind+2);
-
- /* Set kernel alignment to 16M (CONFIG_PHYSICAL_ALIGN) */
- boot->hdr.kernel_alignment = 0x1000000;
-
- /* Boot protocol version: 2.07 supports the fields for lguest. */
- boot->hdr.version = 0x207;
-
- /* X86_SUBARCH_LGUEST tells the Guest it's an lguest. */
- boot->hdr.hardware_subarch = X86_SUBARCH_LGUEST;
-
- /* Tell the entry path not to try to reload segment registers. */
- boot->hdr.loadflags |= KEEP_SEGMENTS;
-
- /* We don't support tboot: */
- boot->tboot_addr = 0;
-
- /* Ensure this is 0 to prevent APM from loading: */
- boot->apm_bios_info.version = 0;
-
- /* We tell the kernel to initialize the Guest. */
- tell_kernel(start);
-
- /* Ensure that we terminate if a device-servicing child dies. */
- signal(SIGCHLD, kill_launcher);
-
- /* If requested, chroot to a directory */
- if (chroot_path) {
- if (chroot(chroot_path) != 0)
- err(1, "chroot(\"%s\") failed", chroot_path);
-
- if (chdir("/") != 0)
- err(1, "chdir(\"/\") failed");
-
- verbose("chroot done\n");
- }
-
- /* If requested, drop privileges */
- if (user_details) {
- uid_t u;
- gid_t g;
-
- u = user_details->pw_uid;
- g = user_details->pw_gid;
-
- if (initgroups(user_details->pw_name, g) != 0)
- err(1, "initgroups failed");
-
- if (setresgid(g, g, g) != 0)
- err(1, "setresgid failed");
-
- if (setresuid(u, u, u) != 0)
- err(1, "setresuid failed");
-
- verbose("Dropping privileges completed\n");
- }
-
- /* Finally, run the Guest. This doesn't return. */
- run_guest();
-}
-/*:*/
-
-/*M:999
- * Mastery is done: you now know everything I do.
- *
- * But surely you have seen code, features and bugs in your wanderings which
- * you now yearn to attack? That is the real game, and I look forward to you
- * patching and forking lguest into the Your-Name-Here-visor.
- *
- * Farewell, and good coding!
- * Rusty Russell.
- */
projects / linux-2.6-block.git / blobdiff