[linux-2.6-block.git] / drivers / tty / hvc / hvc_xen.c

/*
 * xen console driver interface to hvc_console.c
 *
 * (c) 2007 Gerd Hoffmann <kraxel@suse.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/console.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/irq.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/serial_core.h>

#include <asm/io.h>
#include <asm/xen/hypervisor.h>

#include <xen/xen.h>
#include <xen/interface/xen.h>
#include <xen/hvm.h>
#include <xen/grant_table.h>
#include <xen/page.h>
#include <xen/events.h>
#include <xen/interface/io/console.h>
#include <xen/interface/sched.h>
#include <xen/hvc-console.h>
#include <xen/xenbus.h>

#include "hvc_console.h"

#define HVC_COOKIE   0x58656e /* "Xen" in hex */

struct xencons_info {
	struct list_head list;
	struct xenbus_device *xbdev;
	struct xencons_interface *intf;
	unsigned int evtchn;
	struct hvc_struct *hvc;
	int irq;
	int vtermno;
	grant_ref_t gntref;
};

static LIST_HEAD(xenconsoles);
static DEFINE_SPINLOCK(xencons_lock);

/* ------------------------------------------------------------------ */

static struct xencons_info *vtermno_to_xencons(int vtermno)
{
	struct xencons_info *entry, *n, *ret = NULL;

	if (list_empty(&xenconsoles))
			return NULL;

	list_for_each_entry_safe(entry, n, &xenconsoles, list) {
		if (entry->vtermno == vtermno) {
			ret  = entry;
			break;
		}
	}

	return ret;
}

static inline int xenbus_devid_to_vtermno(int devid)
{
	return devid + HVC_COOKIE;
}

static inline void notify_daemon(struct xencons_info *cons)
{
	/* Use evtchn: this is called early, before irq is set up. */
	notify_remote_via_evtchn(cons->evtchn);
}

static int __write_console(struct xencons_info *xencons,
		const char *data, int len)
{
	XENCONS_RING_IDX cons, prod;
	struct xencons_interface *intf = xencons->intf;
	int sent = 0;

	cons = intf->out_cons;
	prod = intf->out_prod;
	mb();			/* update queue values before going on */
	BUG_ON((prod - cons) > sizeof(intf->out));

	while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
		intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];

	wmb();			/* write ring before updating pointer */
	intf->out_prod = prod;

	if (sent)
		notify_daemon(xencons);
	return sent;
}

static int domU_write_console(uint32_t vtermno, const char *data, int len)
{
	int ret = len;
	struct xencons_info *cons = vtermno_to_xencons(vtermno);
	if (cons == NULL)
		return -EINVAL;

	/*
	 * Make sure the whole buffer is emitted, polling if
	 * necessary.  We don't ever want to rely on the hvc daemon
	 * because the most interesting console output is when the
	 * kernel is crippled.
	 */
	while (len) {
		int sent = __write_console(cons, data, len);
		
		data += sent;
		len -= sent;

		if (unlikely(len))
			HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
	}

	return ret;
}

static int domU_read_console(uint32_t vtermno, char *buf, int len)
{
	struct xencons_interface *intf;
	XENCONS_RING_IDX cons, prod;
	int recv = 0;
	struct xencons_info *xencons = vtermno_to_xencons(vtermno);
	if (xencons == NULL)
		return -EINVAL;
	intf = xencons->intf;

	cons = intf->in_cons;
	prod = intf->in_prod;
	mb();			/* get pointers before reading ring */
	BUG_ON((prod - cons) > sizeof(intf->in));

	while (cons != prod && recv < len)
		buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];

	mb();			/* read ring before consuming */
	intf->in_cons = cons;

	notify_daemon(xencons);
	return recv;
}

static const struct hv_ops domU_hvc_ops = {
	.get_chars = domU_read_console,
	.put_chars = domU_write_console,
	.notifier_add = notifier_add_irq,
	.notifier_del = notifier_del_irq,
	.notifier_hangup = notifier_hangup_irq,
};

static int dom0_read_console(uint32_t vtermno, char *buf, int len)
{
	return HYPERVISOR_console_io(CONSOLEIO_read, len, buf);
}

/*
 * Either for a dom0 to write to the system console, or a domU with a
 * debug version of Xen
 */
static int dom0_write_console(uint32_t vtermno, const char *str, int len)
{
	int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (char *)str);
	if (rc < 0)
		return rc;

	return len;
}

static const struct hv_ops dom0_hvc_ops = {
	.get_chars = dom0_read_console,
	.put_chars = dom0_write_console,
	.notifier_add = notifier_add_irq,
	.notifier_del = notifier_del_irq,
	.notifier_hangup = notifier_hangup_irq,
};

static int xen_hvm_console_init(void)
{
	int r;
	uint64_t v = 0;
	unsigned long gfn;
	struct xencons_info *info;

	if (!xen_hvm_domain())
		return -ENODEV;

	info = vtermno_to_xencons(HVC_COOKIE);
	if (!info) {
		info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
		if (!info)
			return -ENOMEM;
	} else if (info->intf != NULL) {
		/* already configured */
		return 0;
	}
	/*
	 * If the toolstack (or the hypervisor) hasn't set these values, the
	 * default value is 0. Even though gfn = 0 and evtchn = 0 are
	 * theoretically correct values, in practice they never are and they
	 * mean that a legacy toolstack hasn't initialized the pv console correctly.
	 */
	r = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
	if (r < 0 || v == 0)
		goto err;
	info->evtchn = v;
	v = 0;
	r = hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
	if (r < 0 || v == 0)
		goto err;
	gfn = v;
	info->intf = xen_remap(gfn << XEN_PAGE_SHIFT, XEN_PAGE_SIZE);
	if (info->intf == NULL)
		goto err;
	info->vtermno = HVC_COOKIE;

	spin_lock(&xencons_lock);
	list_add_tail(&info->list, &xenconsoles);
	spin_unlock(&xencons_lock);

	return 0;
err:
	kfree(info);
	return -ENODEV;
}

static int xencons_info_pv_init(struct xencons_info *info, int vtermno)
{
	info->evtchn = xen_start_info->console.domU.evtchn;
	/* GFN == MFN for PV guest */
	info->intf = gfn_to_virt(xen_start_info->console.domU.mfn);
	info->vtermno = vtermno;

	list_add_tail(&info->list, &xenconsoles);

	return 0;
}

static int xen_pv_console_init(void)
{
	struct xencons_info *info;

	if (!xen_pv_domain())
		return -ENODEV;

	if (!xen_start_info->console.domU.evtchn)
		return -ENODEV;

	info = vtermno_to_xencons(HVC_COOKIE);
	if (!info) {
		info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
		if (!info)
			return -ENOMEM;
	} else if (info->intf != NULL) {
		/* already configured */
		return 0;
	}
	spin_lock(&xencons_lock);
	xencons_info_pv_init(info, HVC_COOKIE);
	spin_unlock(&xencons_lock);

	return 0;
}

static int xen_initial_domain_console_init(void)
{
	struct xencons_info *info;

	if (!xen_initial_domain())
		return -ENODEV;

	info = vtermno_to_xencons(HVC_COOKIE);
	if (!info) {
		info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
		if (!info)
			return -ENOMEM;
	}

	info->irq = bind_virq_to_irq(VIRQ_CONSOLE, 0, false);
	info->vtermno = HVC_COOKIE;

	spin_lock(&xencons_lock);
	list_add_tail(&info->list, &xenconsoles);
	spin_unlock(&xencons_lock);

	return 0;
}

static void xen_console_update_evtchn(struct xencons_info *info)
{
	if (xen_hvm_domain()) {
		uint64_t v = 0;
		int err;

		err = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
		if (!err && v)
			info->evtchn = v;
	} else
		info->evtchn = xen_start_info->console.domU.evtchn;
}

void xen_console_resume(void)
{
	struct xencons_info *info = vtermno_to_xencons(HVC_COOKIE);
	if (info != NULL && info->irq) {
		if (!xen_initial_domain())
			xen_console_update_evtchn(info);
		rebind_evtchn_irq(info->evtchn, info->irq);
	}
}

#ifdef CONFIG_HVC_XEN_FRONTEND
static void xencons_disconnect_backend(struct xencons_info *info)
{
	if (info->irq > 0)
		unbind_from_irqhandler(info->irq, NULL);
	info->irq = 0;
	if (info->evtchn > 0)
		xenbus_free_evtchn(info->xbdev, info->evtchn);
	info->evtchn = 0;
	if (info->gntref > 0)
		gnttab_free_grant_references(info->gntref);
	info->gntref = 0;
	if (info->hvc != NULL)
		hvc_remove(info->hvc);
	info->hvc = NULL;
}

static void xencons_free(struct xencons_info *info)
{
	free_page((unsigned long)info->intf);
	info->intf = NULL;
	info->vtermno = 0;
	kfree(info);
}

static int xen_console_remove(struct xencons_info *info)
{
	xencons_disconnect_backend(info);
	spin_lock(&xencons_lock);
	list_del(&info->list);
	spin_unlock(&xencons_lock);
	if (info->xbdev != NULL)
		xencons_free(info);
	else {
		if (xen_hvm_domain())
			iounmap(info->intf);
		kfree(info);
	}
	return 0;
}

static int xencons_remove(struct xenbus_device *dev)
{
	return xen_console_remove(dev_get_drvdata(&dev->dev));
}

static int xencons_connect_backend(struct xenbus_device *dev,
				  struct xencons_info *info)
{
	int ret, evtchn, devid, ref, irq;
	struct xenbus_transaction xbt;
	grant_ref_t gref_head;

	ret = xenbus_alloc_evtchn(dev, &evtchn);
	if (ret)
		return ret;
	info->evtchn = evtchn;
	irq = bind_evtchn_to_irq(evtchn);
	if (irq < 0)
		return irq;
	info->irq = irq;
	devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
	info->hvc = hvc_alloc(xenbus_devid_to_vtermno(devid),
			irq, &domU_hvc_ops, 256);
	if (IS_ERR(info->hvc))
		return PTR_ERR(info->hvc);
	ret = gnttab_alloc_grant_references(1, &gref_head);
	if (ret < 0)
		return ret;
	info->gntref = gref_head;
	ref = gnttab_claim_grant_reference(&gref_head);
	if (ref < 0)
		return ref;
	gnttab_grant_foreign_access_ref(ref, info->xbdev->otherend_id,
					virt_to_gfn(info->intf), 0);

 again:
	ret = xenbus_transaction_start(&xbt);
	if (ret) {
		xenbus_dev_fatal(dev, ret, "starting transaction");
		return ret;
	}
	ret = xenbus_printf(xbt, dev->nodename, "ring-ref", "%d", ref);
	if (ret)
		goto error_xenbus;
	ret = xenbus_printf(xbt, dev->nodename, "port", "%u",
			    evtchn);
	if (ret)
		goto error_xenbus;
	ret = xenbus_transaction_end(xbt, 0);
	if (ret) {
		if (ret == -EAGAIN)
			goto again;
		xenbus_dev_fatal(dev, ret, "completing transaction");
		return ret;
	}

	xenbus_switch_state(dev, XenbusStateInitialised);
	return 0;

 error_xenbus:
	xenbus_transaction_end(xbt, 1);
	xenbus_dev_fatal(dev, ret, "writing xenstore");
	return ret;
}

static int xencons_probe(struct xenbus_device *dev,
				  const struct xenbus_device_id *id)
{
	int ret, devid;
	struct xencons_info *info;

	devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
	if (devid == 0)
		return -ENODEV;

	info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
	if (!info)
		return -ENOMEM;
	dev_set_drvdata(&dev->dev, info);
	info->xbdev = dev;
	info->vtermno = xenbus_devid_to_vtermno(devid);
	info->intf = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
	if (!info->intf)
		goto error_nomem;

	ret = xencons_connect_backend(dev, info);
	if (ret < 0)
		goto error;
	spin_lock(&xencons_lock);
	list_add_tail(&info->list, &xenconsoles);
	spin_unlock(&xencons_lock);

	return 0;

 error_nomem:
	ret = -ENOMEM;
	xenbus_dev_fatal(dev, ret, "allocating device memory");
 error:
	xencons_disconnect_backend(info);
	xencons_free(info);
	return ret;
}

static int xencons_resume(struct xenbus_device *dev)
{
	struct xencons_info *info = dev_get_drvdata(&dev->dev);

	xencons_disconnect_backend(info);
	memset(info->intf, 0, XEN_PAGE_SIZE);
	return xencons_connect_backend(dev, info);
}

static void xencons_backend_changed(struct xenbus_device *dev,
				   enum xenbus_state backend_state)
{
	switch (backend_state) {
	case XenbusStateReconfiguring:
	case XenbusStateReconfigured:
	case XenbusStateInitialising:
	case XenbusStateInitialised:
	case XenbusStateUnknown:
		break;

	case XenbusStateInitWait:
		break;

	case XenbusStateConnected:
		xenbus_switch_state(dev, XenbusStateConnected);
		break;

	case XenbusStateClosed:
		if (dev->state == XenbusStateClosed)
			break;
		/* Missed the backend's CLOSING state -- fallthrough */
	case XenbusStateClosing:
		xenbus_frontend_closed(dev);
		break;
	}
}

static const struct xenbus_device_id xencons_ids[] = {
	{ "console" },
	{ "" }
};

static struct xenbus_driver xencons_driver = {
	.name = "xenconsole",
	.ids = xencons_ids,
	.probe = xencons_probe,
	.remove = xencons_remove,
	.resume = xencons_resume,
	.otherend_changed = xencons_backend_changed,
};
#endif /* CONFIG_HVC_XEN_FRONTEND */

static int __init xen_hvc_init(void)
{
	int r;
	struct xencons_info *info;
	const struct hv_ops *ops;

	if (!xen_domain())
		return -ENODEV;

	if (xen_initial_domain()) {
		ops = &dom0_hvc_ops;
		r = xen_initial_domain_console_init();
		if (r < 0)
			return r;
		info = vtermno_to_xencons(HVC_COOKIE);
	} else {
		ops = &domU_hvc_ops;
		if (xen_hvm_domain())
			r = xen_hvm_console_init();
		else
			r = xen_pv_console_init();
		if (r < 0)
			return r;

		info = vtermno_to_xencons(HVC_COOKIE);
		info->irq = bind_evtchn_to_irq(info->evtchn);
	}
	if (info->irq < 0)
		info->irq = 0; /* NO_IRQ */
	else
		irq_set_noprobe(info->irq);

	info->hvc = hvc_alloc(HVC_COOKIE, info->irq, ops, 256);
	if (IS_ERR(info->hvc)) {
		r = PTR_ERR(info->hvc);
		spin_lock(&xencons_lock);
		list_del(&info->list);
		spin_unlock(&xencons_lock);
		if (info->irq)
			unbind_from_irqhandler(info->irq, NULL);
		kfree(info);
		return r;
	}

	r = 0;
#ifdef CONFIG_HVC_XEN_FRONTEND
	r = xenbus_register_frontend(&xencons_driver);
#endif
	return r;
}
device_initcall(xen_hvc_init);

static int xen_cons_init(void)
{
	const struct hv_ops *ops;

	if (!xen_domain())
		return 0;

	if (xen_initial_domain())
		ops = &dom0_hvc_ops;
	else {
		int r;
		ops = &domU_hvc_ops;

		if (xen_hvm_domain())
			r = xen_hvm_console_init();
		else
			r = xen_pv_console_init();
		if (r < 0)
			return r;
	}

	hvc_instantiate(HVC_COOKIE, 0, ops);
	return 0;
}
console_initcall(xen_cons_init);

#ifdef CONFIG_X86
static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len)
{
	if (xen_cpuid_base())
		outsb(0xe9, str, len);
}
#else
static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len) { }
#endif

#ifdef CONFIG_EARLY_PRINTK
static int __init xenboot_setup_console(struct console *console, char *string)
{
	static struct xencons_info xenboot;

	if (xen_initial_domain())
		return 0;
	if (!xen_pv_domain())
		return -ENODEV;

	return xencons_info_pv_init(&xenboot, 0);
}

static void xenboot_write_console(struct console *console, const char *string,
				  unsigned len)
{
	unsigned int linelen, off = 0;
	const char *pos;

	if (!xen_pv_domain()) {
		xen_hvm_early_write(0, string, len);
		return;
	}

	dom0_write_console(0, string, len);

	if (xen_initial_domain())
		return;

	domU_write_console(0, "(early) ", 8);
	while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
		linelen = pos-string+off;
		if (off + linelen > len)
			break;
		domU_write_console(0, string+off, linelen);
		domU_write_console(0, "\r\n", 2);
		off += linelen + 1;
	}
	if (off < len)
		domU_write_console(0, string+off, len-off);
}

struct console xenboot_console = {
	.name		= "xenboot",
	.write		= xenboot_write_console,
	.setup		= xenboot_setup_console,
	.flags		= CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME,
	.index		= -1,
};
#endif	/* CONFIG_EARLY_PRINTK */

void xen_raw_console_write(const char *str)
{
	ssize_t len = strlen(str);
	int rc = 0;

	if (xen_domain()) {
		rc = dom0_write_console(0, str, len);
		if (rc != -ENOSYS || !xen_hvm_domain())
			return;
	}
	xen_hvm_early_write(0, str, len);
}

void xen_raw_printk(const char *fmt, ...)
{
	static char buf[512];
	va_list ap;

	va_start(ap, fmt);
	vsnprintf(buf, sizeof(buf), fmt, ap);
	va_end(ap);

	xen_raw_console_write(buf);
}

static void xenboot_earlycon_write(struct console *console,
				  const char *string,
				  unsigned len)
{
	dom0_write_console(0, string, len);
}

static int __init xenboot_earlycon_setup(struct earlycon_device *device,
					    const char *opt)
{
	device->con->write = xenboot_earlycon_write;
	return 0;
}
EARLYCON_DECLARE(xenboot, xenboot_earlycon_setup);
Commit	Line	Data
b536b4b9 JF	1	/*
	2	* xen console driver interface to hvc_console.c
	3	*
	4	* (c) 2007 Gerd Hoffmann <kraxel@suse.de>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program; if not, write to the Free Software
	18	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	19	*/
	20
	21	#include <linux/console.h>
	22	#include <linux/delay.h>
	23	#include <linux/err.h>
4d9310e3	24	#include <linux/irq.h>
b536b4b9 JF	25	#include <linux/init.h>
b536b4b9 JF	26	#include <linux/types.h>
02e19f9c	27	#include <linux/list.h>
16e506ef	28	#include <linux/serial_core.h>
b536b4b9	29
eb5ef071	30	#include <asm/io.h>
b536b4b9	31	#include <asm/xen/hypervisor.h>
1ccbf534 JF	32
1ccbf534 JF	33	#include <xen/xen.h>
eb5ef071 SS	34	#include <xen/interface/xen.h>
eb5ef071 SS	35	#include <xen/hvm.h>
02e19f9c	36	#include <xen/grant_table.h>
b536b4b9 JF	37	#include <xen/page.h>
	38	#include <xen/events.h>
	39	#include <xen/interface/io/console.h>
4d9310e3	40	#include <xen/interface/sched.h>
b536b4b9	41	#include <xen/hvc-console.h>
02e19f9c	42	#include <xen/xenbus.h>
b536b4b9 JF	43
	44	#include "hvc_console.h"
	45
	46	#define HVC_COOKIE 0x58656e /* "Xen" in hex */
	47
02e19f9c SS	48	struct xencons_info {
	49	struct list_head list;
	50	struct xenbus_device *xbdev;
	51	struct xencons_interface *intf;
	52	unsigned int evtchn;
	53	struct hvc_struct *hvc;
	54	int irq;
	55	int vtermno;
	56	grant_ref_t gntref;
	57	};
	58
	59	static LIST_HEAD(xenconsoles);
	60	static DEFINE_SPINLOCK(xencons_lock);
b536b4b9 JF	61
	62	/* ------------------------------------------------------------------ */
	63
02e19f9c SS	64	static struct xencons_info *vtermno_to_xencons(int vtermno)
	65	{
	66	struct xencons_info entry, n, *ret = NULL;
	67
	68	if (list_empty(&xenconsoles))
	69	return NULL;
	70
	71	list_for_each_entry_safe(entry, n, &xenconsoles, list) {
	72	if (entry->vtermno == vtermno) {
	73	ret = entry;
	74	break;
	75	}
	76	}
6b9b732d	77
02e19f9c SS	78	return ret;
	79	}
	80
	81	static inline int xenbus_devid_to_vtermno(int devid)
b536b4b9	82	{
02e19f9c	83	return devid + HVC_COOKIE;
b536b4b9 JF	84	}
b536b4b9 JF	85
02e19f9c	86	static inline void notify_daemon(struct xencons_info *cons)
b536b4b9 JF	87	{
b536b4b9 JF	88	/* Use evtchn: this is called early, before irq is set up. */
02e19f9c	89	notify_remote_via_evtchn(cons->evtchn);
b536b4b9 JF	90	}
b536b4b9 JF	91
02e19f9c SS	92	static int __write_console(struct xencons_info *xencons,
02e19f9c SS	93	const char *data, int len)
b536b4b9	94	{
b536b4b9	95	XENCONS_RING_IDX cons, prod;
02e19f9c	96	struct xencons_interface *intf = xencons->intf;
b536b4b9 JF	97	int sent = 0;
	98
	99	cons = intf->out_cons;
	100	prod = intf->out_prod;
	101	mb(); /* update queue values before going on */
	102	BUG_ON((prod - cons) > sizeof(intf->out));
	103
	104	while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
	105	intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];
	106
	107	wmb(); /* write ring before updating pointer */
	108	intf->out_prod = prod;
	109
403a85ff	110	if (sent)
02e19f9c	111	notify_daemon(xencons);
b536b4b9 JF	112	return sent;
	113	}
	114
4fe7d5a7	115	static int domU_write_console(uint32_t vtermno, const char *data, int len)
7825cf10 JF	116	{
7825cf10 JF	117	int ret = len;
02e19f9c SS	118	struct xencons_info *cons = vtermno_to_xencons(vtermno);
	119	if (cons == NULL)
	120	return -EINVAL;
7825cf10 JF	121
	122	/*
	123	* Make sure the whole buffer is emitted, polling if
	124	* necessary. We don't ever want to rely on the hvc daemon
	125	* because the most interesting console output is when the
	126	* kernel is crippled.
	127	*/
	128	while (len) {
02e19f9c	129	int sent = __write_console(cons, data, len);
7825cf10 JF	130
	131	data += sent;
	132	len -= sent;
	133
	134	if (unlikely(len))
	135	HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
	136	}
	137
	138	return ret;
	139	}
	140
4fe7d5a7	141	static int domU_read_console(uint32_t vtermno, char *buf, int len)
b536b4b9	142	{
02e19f9c	143	struct xencons_interface *intf;
b536b4b9 JF	144	XENCONS_RING_IDX cons, prod;
b536b4b9 JF	145	int recv = 0;
02e19f9c SS	146	struct xencons_info *xencons = vtermno_to_xencons(vtermno);
	147	if (xencons == NULL)
	148	return -EINVAL;
	149	intf = xencons->intf;
b536b4b9 JF	150
	151	cons = intf->in_cons;
	152	prod = intf->in_prod;
	153	mb(); /* get pointers before reading ring */
	154	BUG_ON((prod - cons) > sizeof(intf->in));
	155
	156	while (cons != prod && recv < len)
	157	buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];
	158
	159	mb(); /* read ring before consuming */
	160	intf->in_cons = cons;
	161
02e19f9c	162	notify_daemon(xencons);
b536b4b9 JF	163	return recv;
	164	}
	165
54573c4a	166	static const struct hv_ops domU_hvc_ops = {
4fe7d5a7 JF	167	.get_chars = domU_read_console,
4fe7d5a7 JF	168	.put_chars = domU_write_console,
611e097d CB	169	.notifier_add = notifier_add_irq,
611e097d CB	170	.notifier_del = notifier_del_irq,
fc362e2e	171	.notifier_hangup = notifier_hangup_irq,
b536b4b9 JF	172	};
b536b4b9 JF	173
4fe7d5a7 JF	174	static int dom0_read_console(uint32_t vtermno, char *buf, int len)
	175	{
	176	return HYPERVISOR_console_io(CONSOLEIO_read, len, buf);
	177	}
	178
	179	/*
	180	* Either for a dom0 to write to the system console, or a domU with a
	181	* debug version of Xen
	182	*/
	183	static int dom0_write_console(uint32_t vtermno, const char *str, int len)
	184	{
	185	int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (char *)str);
	186	if (rc < 0)
04b772d2	187	return rc;
4fe7d5a7 JF	188
	189	return len;
	190	}
	191
54573c4a	192	static const struct hv_ops dom0_hvc_ops = {
4fe7d5a7 JF	193	.get_chars = dom0_read_console,
	194	.put_chars = dom0_write_console,
	195	.notifier_add = notifier_add_irq,
	196	.notifier_del = notifier_del_irq,
	197	.notifier_hangup = notifier_hangup_irq,
	198	};
	199
eb5ef071 SS	200	static int xen_hvm_console_init(void)
	201	{
	202	int r;
	203	uint64_t v = 0;
859e3267	204	unsigned long gfn;
02e19f9c	205	struct xencons_info *info;
eb5ef071 SS	206
	207	if (!xen_hvm_domain())
	208	return -ENODEV;
	209
02e19f9c SS	210	info = vtermno_to_xencons(HVC_COOKIE);
02e19f9c SS	211	if (!info) {
2d1d3f3a	212	info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
02e19f9c SS	213	if (!info)
02e19f9c SS	214	return -ENOMEM;
37a80bf5 KRW	215	} else if (info->intf != NULL) {
37a80bf5 KRW	216	/* already configured */
02e19f9c	217	return 0;
37a80bf5	218	}
5842f576 KRW	219	/*
5842f576 KRW	220	* If the toolstack (or the hypervisor) hasn't set these values, the
859e3267	221	* default value is 0. Even though gfn = 0 and evtchn = 0 are
5842f576 KRW	222	* theoretically correct values, in practice they never are and they
	223	* mean that a legacy toolstack hasn't initialized the pv console correctly.
	224	*/
eb5ef071	225	r = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
5842f576	226	if (r < 0 \|\| v == 0)
2e5ad6b9	227	goto err;
02e19f9c	228	info->evtchn = v;
a32c88b9 KRW	229	v = 0;
a32c88b9 KRW	230	r = hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
5842f576	231	if (r < 0 \|\| v == 0)
2e5ad6b9	232	goto err;
859e3267	233	gfn = v;
9652c080	234	info->intf = xen_remap(gfn << XEN_PAGE_SHIFT, XEN_PAGE_SIZE);
2e5ad6b9 KRW	235	if (info->intf == NULL)
2e5ad6b9 KRW	236	goto err;
02e19f9c SS	237	info->vtermno = HVC_COOKIE;
	238
	239	spin_lock(&xencons_lock);
	240	list_add_tail(&info->list, &xenconsoles);
	241	spin_unlock(&xencons_lock);
	242
	243	return 0;
2e5ad6b9 KRW	244	err:
	245	kfree(info);
	246	return -ENODEV;
02e19f9c SS	247	}
02e19f9c SS	248
5de738b3 SS	249	static int xencons_info_pv_init(struct xencons_info *info, int vtermno)
	250	{
	251	info->evtchn = xen_start_info->console.domU.evtchn;
	252	/* GFN == MFN for PV guest */
	253	info->intf = gfn_to_virt(xen_start_info->console.domU.mfn);
	254	info->vtermno = vtermno;
	255
	256	list_add_tail(&info->list, &xenconsoles);
	257
	258	return 0;
	259	}
	260
02e19f9c SS	261	static int xen_pv_console_init(void)
	262	{
	263	struct xencons_info *info;
	264
	265	if (!xen_pv_domain())
	266	return -ENODEV;
	267
	268	if (!xen_start_info->console.domU.evtchn)
	269	return -ENODEV;
	270
	271	info = vtermno_to_xencons(HVC_COOKIE);
	272	if (!info) {
2d1d3f3a	273	info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
02e19f9c SS	274	if (!info)
02e19f9c SS	275	return -ENOMEM;
37a80bf5 KRW	276	} else if (info->intf != NULL) {
37a80bf5 KRW	277	/* already configured */
02e19f9c	278	return 0;
37a80bf5	279	}
02e19f9c	280	spin_lock(&xencons_lock);
5de738b3	281	xencons_info_pv_init(info, HVC_COOKIE);
02e19f9c SS	282	spin_unlock(&xencons_lock);
	283
	284	return 0;
	285	}
	286
	287	static int xen_initial_domain_console_init(void)
	288	{
	289	struct xencons_info *info;
	290
	291	if (!xen_initial_domain())
	292	return -ENODEV;
	293
	294	info = vtermno_to_xencons(HVC_COOKIE);
	295	if (!info) {
2d1d3f3a	296	info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
02e19f9c SS	297	if (!info)
	298	return -ENOMEM;
	299	}
	300
77bb3dfd	301	info->irq = bind_virq_to_irq(VIRQ_CONSOLE, 0, false);
02e19f9c SS	302	info->vtermno = HVC_COOKIE;
	303
	304	spin_lock(&xencons_lock);
	305	list_add_tail(&info->list, &xenconsoles);
	306	spin_unlock(&xencons_lock);
eb5ef071 SS	307
	308	return 0;
	309	}
	310
b9d934f2 BO	311	static void xen_console_update_evtchn(struct xencons_info *info)
	312	{
	313	if (xen_hvm_domain()) {
c4ace5da	314	uint64_t v = 0;
b9d934f2 BO	315	int err;
	316
	317	err = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
	318	if (!err && v)
	319	info->evtchn = v;
	320	} else
	321	info->evtchn = xen_start_info->console.domU.evtchn;
	322	}
	323
02e19f9c SS	324	void xen_console_resume(void)
	325	{
	326	struct xencons_info *info = vtermno_to_xencons(HVC_COOKIE);
b9d934f2 BO	327	if (info != NULL && info->irq) {
	328	if (!xen_initial_domain())
	329	xen_console_update_evtchn(info);
02e19f9c	330	rebind_evtchn_irq(info->evtchn, info->irq);
b9d934f2	331	}
02e19f9c SS	332	}
02e19f9c SS	333
e36ae343	334	#ifdef CONFIG_HVC_XEN_FRONTEND
02e19f9c SS	335	static void xencons_disconnect_backend(struct xencons_info *info)
	336	{
	337	if (info->irq > 0)
	338	unbind_from_irqhandler(info->irq, NULL);
	339	info->irq = 0;
	340	if (info->evtchn > 0)
	341	xenbus_free_evtchn(info->xbdev, info->evtchn);
	342	info->evtchn = 0;
	343	if (info->gntref > 0)
	344	gnttab_free_grant_references(info->gntref);
	345	info->gntref = 0;
	346	if (info->hvc != NULL)
	347	hvc_remove(info->hvc);
	348	info->hvc = NULL;
	349	}
	350
	351	static void xencons_free(struct xencons_info *info)
	352	{
	353	free_page((unsigned long)info->intf);
	354	info->intf = NULL;
	355	info->vtermno = 0;
	356	kfree(info);
	357	}
	358
	359	static int xen_console_remove(struct xencons_info *info)
	360	{
	361	xencons_disconnect_backend(info);
	362	spin_lock(&xencons_lock);
	363	list_del(&info->list);
	364	spin_unlock(&xencons_lock);
	365	if (info->xbdev != NULL)
	366	xencons_free(info);
	367	else {
	368	if (xen_hvm_domain())
	369	iounmap(info->intf);
	370	kfree(info);
4fe7d5a7	371	}
02e19f9c SS	372	return 0;
02e19f9c SS	373	}
6b9b732d	374
02e19f9c SS	375	static int xencons_remove(struct xenbus_device *dev)
	376	{
	377	return xen_console_remove(dev_get_drvdata(&dev->dev));
	378	}
b536b4b9	379
02e19f9c SS	380	static int xencons_connect_backend(struct xenbus_device *dev,
	381	struct xencons_info *info)
	382	{
	383	int ret, evtchn, devid, ref, irq;
	384	struct xenbus_transaction xbt;
	385	grant_ref_t gref_head;
02e19f9c SS	386
	387	ret = xenbus_alloc_evtchn(dev, &evtchn);
	388	if (ret)
	389	return ret;
	390	info->evtchn = evtchn;
	391	irq = bind_evtchn_to_irq(evtchn);
	392	if (irq < 0)
	393	return irq;
	394	info->irq = irq;
	395	devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
	396	info->hvc = hvc_alloc(xenbus_devid_to_vtermno(devid),
	397	irq, &domU_hvc_ops, 256);
	398	if (IS_ERR(info->hvc))
	399	return PTR_ERR(info->hvc);
02e19f9c SS	400	ret = gnttab_alloc_grant_references(1, &gref_head);
	401	if (ret < 0)
	402	return ret;
	403	info->gntref = gref_head;
	404	ref = gnttab_claim_grant_reference(&gref_head);
	405	if (ref < 0)
	406	return ref;
	407	gnttab_grant_foreign_access_ref(ref, info->xbdev->otherend_id,
859e3267	408	virt_to_gfn(info->intf), 0);
02e19f9c SS	409
	410	again:
	411	ret = xenbus_transaction_start(&xbt);
	412	if (ret) {
	413	xenbus_dev_fatal(dev, ret, "starting transaction");
	414	return ret;
	415	}
	416	ret = xenbus_printf(xbt, dev->nodename, "ring-ref", "%d", ref);
	417	if (ret)
	418	goto error_xenbus;
	419	ret = xenbus_printf(xbt, dev->nodename, "port", "%u",
	420	evtchn);
02e19f9c SS	421	if (ret)
	422	goto error_xenbus;
	423	ret = xenbus_transaction_end(xbt, 0);
	424	if (ret) {
	425	if (ret == -EAGAIN)
	426	goto again;
	427	xenbus_dev_fatal(dev, ret, "completing transaction");
	428	return ret;
	429	}
6b9b732d	430
02e19f9c	431	xenbus_switch_state(dev, XenbusStateInitialised);
b536b4b9	432	return 0;
02e19f9c SS	433
	434	error_xenbus:
	435	xenbus_transaction_end(xbt, 1);
	436	xenbus_dev_fatal(dev, ret, "writing xenstore");
	437	return ret;
b536b4b9 JF	438	}
b536b4b9 JF	439
9671f099	440	static int xencons_probe(struct xenbus_device *dev,
02e19f9c	441	const struct xenbus_device_id *id)
6b9b732d	442	{
02e19f9c SS	443	int ret, devid;
	444	struct xencons_info *info;
	445
	446	devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
	447	if (devid == 0)
	448	return -ENODEV;
	449
201a52be	450	info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
02e19f9c	451	if (!info)
201a52be	452	return -ENOMEM;
02e19f9c SS	453	dev_set_drvdata(&dev->dev, info);
	454	info->xbdev = dev;
	455	info->vtermno = xenbus_devid_to_vtermno(devid);
	456	info->intf = (void *)__get_free_page(GFP_KERNEL \| __GFP_ZERO);
	457	if (!info->intf)
	458	goto error_nomem;
	459
	460	ret = xencons_connect_backend(dev, info);
	461	if (ret < 0)
	462	goto error;
	463	spin_lock(&xencons_lock);
	464	list_add_tail(&info->list, &xenconsoles);
	465	spin_unlock(&xencons_lock);
	466
	467	return 0;
	468
	469	error_nomem:
	470	ret = -ENOMEM;
	471	xenbus_dev_fatal(dev, ret, "allocating device memory");
	472	error:
	473	xencons_disconnect_backend(info);
	474	xencons_free(info);
	475	return ret;
	476	}
	477
	478	static int xencons_resume(struct xenbus_device *dev)
	479	{
	480	struct xencons_info *info = dev_get_drvdata(&dev->dev);
	481
	482	xencons_disconnect_backend(info);
9652c080	483	memset(info->intf, 0, XEN_PAGE_SIZE);
02e19f9c	484	return xencons_connect_backend(dev, info);
6b9b732d JF	485	}
6b9b732d JF	486
02e19f9c SS	487	static void xencons_backend_changed(struct xenbus_device *dev,
	488	enum xenbus_state backend_state)
	489	{
	490	switch (backend_state) {
	491	case XenbusStateReconfiguring:
	492	case XenbusStateReconfigured:
	493	case XenbusStateInitialising:
	494	case XenbusStateInitialised:
	495	case XenbusStateUnknown:
02e19f9c SS	496	break;
	497
	498	case XenbusStateInitWait:
	499	break;
	500
	501	case XenbusStateConnected:
	502	xenbus_switch_state(dev, XenbusStateConnected);
	503	break;
	504
9b6934a3 DV	505	case XenbusStateClosed:
	506	if (dev->state == XenbusStateClosed)
	507	break;
	508	/* Missed the backend's CLOSING state -- fallthrough */
02e19f9c SS	509	case XenbusStateClosing:
	510	xenbus_frontend_closed(dev);
	511	break;
	512	}
	513	}
	514
	515	static const struct xenbus_device_id xencons_ids[] = {
	516	{ "console" },
	517	{ "" }
	518	};
	519
95afae48 DV	520	static struct xenbus_driver xencons_driver = {
	521	.name = "xenconsole",
	522	.ids = xencons_ids,
cf8e019b SS	523	.probe = xencons_probe,
	524	.remove = xencons_remove,
	525	.resume = xencons_resume,
	526	.otherend_changed = xencons_backend_changed,
95afae48	527	};
cf8e019b SS	528	#endif /* CONFIG_HVC_XEN_FRONTEND */
	529
	530	static int __init xen_hvc_init(void)
	531	{
	532	int r;
	533	struct xencons_info *info;
	534	const struct hv_ops *ops;
	535
	536	if (!xen_domain())
	537	return -ENODEV;
	538
	539	if (xen_initial_domain()) {
	540	ops = &dom0_hvc_ops;
	541	r = xen_initial_domain_console_init();
	542	if (r < 0)
	543	return r;
	544	info = vtermno_to_xencons(HVC_COOKIE);
	545	} else {
	546	ops = &domU_hvc_ops;
	547	if (xen_hvm_domain())
	548	r = xen_hvm_console_init();
	549	else
	550	r = xen_pv_console_init();
	551	if (r < 0)
	552	return r;
	553
	554	info = vtermno_to_xencons(HVC_COOKIE);
	555	info->irq = bind_evtchn_to_irq(info->evtchn);
	556	}
	557	if (info->irq < 0)
	558	info->irq = 0; /* NO_IRQ */
	559	else
	560	irq_set_noprobe(info->irq);
	561
	562	info->hvc = hvc_alloc(HVC_COOKIE, info->irq, ops, 256);
	563	if (IS_ERR(info->hvc)) {
	564	r = PTR_ERR(info->hvc);
	565	spin_lock(&xencons_lock);
	566	list_del(&info->list);
	567	spin_unlock(&xencons_lock);
	568	if (info->irq)
	569	unbind_from_irqhandler(info->irq, NULL);
	570	kfree(info);
	571	return r;
	572	}
	573
	574	r = 0;
	575	#ifdef CONFIG_HVC_XEN_FRONTEND
	576	r = xenbus_register_frontend(&xencons_driver);
	577	#endif
	578	return r;
	579	}
4fedd0bf	580	device_initcall(xen_hvc_init);
b536b4b9 JF	581
	582	static int xen_cons_init(void)
	583	{
eb5ef071	584	const struct hv_ops *ops;
4fe7d5a7	585
eb5ef071	586	if (!xen_domain())
b536b4b9 JF	587	return 0;
b536b4b9 JF	588
4fe7d5a7 JF	589	if (xen_initial_domain())
4fe7d5a7 JF	590	ops = &dom0_hvc_ops;
eb5ef071	591	else {
02e19f9c	592	int r;
4fe7d5a7 JF	593	ops = &domU_hvc_ops;
4fe7d5a7 JF	594
02e19f9c SS	595	if (xen_hvm_domain())
02e19f9c SS	596	r = xen_hvm_console_init();
eb5ef071	597	else
02e19f9c SS	598	r = xen_pv_console_init();
	599	if (r < 0)
	600	return r;
eb5ef071 SS	601	}
eb5ef071 SS	602
4fe7d5a7	603	hvc_instantiate(HVC_COOKIE, 0, ops);
b536b4b9 JF	604	return 0;
b536b4b9 JF	605	}
b536b4b9 JF	606	console_initcall(xen_cons_init);
b536b4b9 JF	607
a4d7b75b SS	608	#ifdef CONFIG_X86
	609	static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len)
	610	{
	611	if (xen_cpuid_base())
	612	outsb(0xe9, str, len);
	613	}
	614	#else
	615	static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len) { }
	616	#endif
	617
0922abdc	618	#ifdef CONFIG_EARLY_PRINTK
5de738b3 SS	619	static int __init xenboot_setup_console(struct console console, char string)
	620	{
	621	static struct xencons_info xenboot;
	622
	623	if (xen_initial_domain())
	624	return 0;
	625	if (!xen_pv_domain())
	626	return -ENODEV;
	627
	628	return xencons_info_pv_init(&xenboot, 0);
	629	}
	630
b536b4b9 JF	631	static void xenboot_write_console(struct console console, const char string,
	632	unsigned len)
	633	{
	634	unsigned int linelen, off = 0;
	635	const char *pos;
	636
a4d7b75b SS	637	if (!xen_pv_domain()) {
a4d7b75b SS	638	xen_hvm_early_write(0, string, len);
eb5ef071	639	return;
a4d7b75b	640	}
eb5ef071	641
4fe7d5a7 JF	642	dom0_write_console(0, string, len);
	643
	644	if (xen_initial_domain())
	645	return;
0922abdc	646
4fe7d5a7	647	domU_write_console(0, "(early) ", 8);
b536b4b9 JF	648	while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
	649	linelen = pos-string+off;
	650	if (off + linelen > len)
	651	break;
4fe7d5a7 JF	652	domU_write_console(0, string+off, linelen);
4fe7d5a7 JF	653	domU_write_console(0, "\r\n", 2);
b536b4b9 JF	654	off += linelen + 1;
	655	}
	656	if (off < len)
4fe7d5a7	657	domU_write_console(0, string+off, len-off);
b536b4b9 JF	658	}
	659
	660	struct console xenboot_console = {
	661	.name = "xenboot",
	662	.write = xenboot_write_console,
5de738b3	663	.setup = xenboot_setup_console,
0922abdc	664	.flags = CON_PRINTBUFFER \| CON_BOOT \| CON_ANYTIME,
a9fbf4d5	665	.index = -1,
b536b4b9	666	};
0922abdc	667	#endif /* CONFIG_EARLY_PRINTK */
0acf10d8 JF	668
	669	void xen_raw_console_write(const char *str)
	670	{
04b772d2 KRW	671	ssize_t len = strlen(str);
	672	int rc = 0;
	673
	674	if (xen_domain()) {
	675	rc = dom0_write_console(0, str, len);
a4d7b75b SS	676	if (rc != -ENOSYS \|\| !xen_hvm_domain())
a4d7b75b SS	677	return;
04b772d2	678	}
a4d7b75b	679	xen_hvm_early_write(0, str, len);
0acf10d8 JF	680	}
	681
	682	void xen_raw_printk(const char *fmt, ...)
	683	{
	684	static char buf[512];
	685	va_list ap;
	686
	687	va_start(ap, fmt);
	688	vsnprintf(buf, sizeof(buf), fmt, ap);
	689	va_end(ap);
	690
	691	xen_raw_console_write(buf);
	692	}
16e506ef SS	693
	694	static void xenboot_earlycon_write(struct console *console,
	695	const char *string,
	696	unsigned len)
	697	{
	698	dom0_write_console(0, string, len);
	699	}
	700
	701	static int __init xenboot_earlycon_setup(struct earlycon_device *device,
	702	const char *opt)
	703	{
	704	device->con->write = xenboot_earlycon_write;
	705	return 0;
	706	}
	707	EARLYCON_DECLARE(xenboot, xenboot_earlycon_setup);