4 * This file contains the various mmu fetch and update operations.
5 * The most important job they must perform is the mapping between the
6 * domain's pfn and the overall machine mfns.
8 * Xen allows guests to directly update the pagetable, in a controlled
9 * fashion. In other words, the guest modifies the same pagetable
10 * that the CPU actually uses, which eliminates the overhead of having
11 * a separate shadow pagetable.
13 * In order to allow this, it falls on the guest domain to map its
14 * notion of a "physical" pfn - which is just a domain-local linear
15 * address - into a real "machine address" which the CPU's MMU can
18 * A pgd_t/pmd_t/pte_t will typically contain an mfn, and so can be
19 * inserted directly into the pagetable. When creating a new
20 * pte/pmd/pgd, it converts the passed pfn into an mfn. Conversely,
21 * when reading the content back with __(pgd|pmd|pte)_val, it converts
22 * the mfn back into a pfn.
24 * The other constraint is that all pages which make up a pagetable
25 * must be mapped read-only in the guest. This prevents uncontrolled
26 * guest updates to the pagetable. Xen strictly enforces this, and
27 * will disallow any pagetable update which will end up mapping a
28 * pagetable page RW, and will disallow using any writable page as a
31 * Naively, when loading %cr3 with the base of a new pagetable, Xen
32 * would need to validate the whole pagetable before going on.
33 * Naturally, this is quite slow. The solution is to "pin" a
34 * pagetable, which enforces all the constraints on the pagetable even
35 * when it is not actively in use. This menas that Xen can be assured
36 * that it is still valid when you do load it into %cr3, and doesn't
37 * need to revalidate it.
39 * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
41 #include <linux/sched/mm.h>
42 #include <linux/highmem.h>
43 #include <linux/debugfs.h>
44 #include <linux/bug.h>
45 #include <linux/vmalloc.h>
46 #include <linux/export.h>
47 #include <linux/init.h>
48 #include <linux/gfp.h>
49 #include <linux/memblock.h>
50 #include <linux/seq_file.h>
51 #include <linux/crash_dump.h>
52 #ifdef CONFIG_KEXEC_CORE
53 #include <linux/kexec.h>
56 #include <trace/events/xen.h>
58 #include <asm/pgtable.h>
59 #include <asm/tlbflush.h>
60 #include <asm/fixmap.h>
61 #include <asm/mmu_context.h>
62 #include <asm/setup.h>
63 #include <asm/paravirt.h>
64 #include <asm/e820/api.h>
65 #include <asm/linkage.h>
71 #include <asm/xen/hypercall.h>
72 #include <asm/xen/hypervisor.h>
76 #include <xen/interface/xen.h>
77 #include <xen/interface/hvm/hvm_op.h>
78 #include <xen/interface/version.h>
79 #include <xen/interface/memory.h>
80 #include <xen/hvc-console.h>
82 #include "multicalls.h"
88 * Identity map, in addition to plain kernel map. This needs to be
89 * large enough to allocate page table pages to allocate the rest.
90 * Each page can map 2MB.
92 #define LEVEL1_IDENT_ENTRIES (PTRS_PER_PTE * 4)
93 static RESERVE_BRK_ARRAY(pte_t, level1_ident_pgt, LEVEL1_IDENT_ENTRIES);
96 /* l3 pud for userspace vsyscall mapping */
97 static pud_t level3_user_vsyscall[PTRS_PER_PUD] __page_aligned_bss;
98 #endif /* CONFIG_X86_64 */
101 * Note about cr3 (pagetable base) values:
103 * xen_cr3 contains the current logical cr3 value; it contains the
104 * last set cr3. This may not be the current effective cr3, because
105 * its update may be being lazily deferred. However, a vcpu looking
106 * at its own cr3 can use this value knowing that it everything will
107 * be self-consistent.
109 * xen_current_cr3 contains the actual vcpu cr3; it is set once the
110 * hypercall to set the vcpu cr3 is complete (so it may be a little
111 * out of date, but it will never be set early). If one vcpu is
112 * looking at another vcpu's cr3 value, it should use this variable.
114 DEFINE_PER_CPU(unsigned long, xen_cr3); /* cr3 stored as physaddr */
115 DEFINE_PER_CPU(unsigned long, xen_current_cr3); /* actual vcpu cr3 */
117 static phys_addr_t xen_pt_base, xen_pt_size __initdata;
120 * Just beyond the highest usermode address. STACK_TOP_MAX has a
121 * redzone above it, so round it up to a PGD boundary.
123 #define USER_LIMIT ((STACK_TOP_MAX + PGDIR_SIZE - 1) & PGDIR_MASK)
125 void make_lowmem_page_readonly(void *vaddr)
128 unsigned long address = (unsigned long)vaddr;
131 pte = lookup_address(address, &level);
133 return; /* vaddr missing */
135 ptev = pte_wrprotect(*pte);
137 if (HYPERVISOR_update_va_mapping(address, ptev, 0))
141 void make_lowmem_page_readwrite(void *vaddr)
144 unsigned long address = (unsigned long)vaddr;
147 pte = lookup_address(address, &level);
149 return; /* vaddr missing */
151 ptev = pte_mkwrite(*pte);
153 if (HYPERVISOR_update_va_mapping(address, ptev, 0))
158 static bool xen_page_pinned(void *ptr)
160 struct page *page = virt_to_page(ptr);
162 return PagePinned(page);
165 static void xen_extend_mmu_update(const struct mmu_update *update)
167 struct multicall_space mcs;
168 struct mmu_update *u;
170 mcs = xen_mc_extend_args(__HYPERVISOR_mmu_update, sizeof(*u));
172 if (mcs.mc != NULL) {
175 mcs = __xen_mc_entry(sizeof(*u));
176 MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
183 static void xen_extend_mmuext_op(const struct mmuext_op *op)
185 struct multicall_space mcs;
188 mcs = xen_mc_extend_args(__HYPERVISOR_mmuext_op, sizeof(*u));
190 if (mcs.mc != NULL) {
193 mcs = __xen_mc_entry(sizeof(*u));
194 MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
201 static void xen_set_pmd_hyper(pmd_t *ptr, pmd_t val)
209 /* ptr may be ioremapped for 64-bit pagetable setup */
210 u.ptr = arbitrary_virt_to_machine(ptr).maddr;
211 u.val = pmd_val_ma(val);
212 xen_extend_mmu_update(&u);
214 xen_mc_issue(PARAVIRT_LAZY_MMU);
219 static void xen_set_pmd(pmd_t *ptr, pmd_t val)
221 trace_xen_mmu_set_pmd(ptr, val);
223 /* If page is not pinned, we can just update the entry
225 if (!xen_page_pinned(ptr)) {
230 xen_set_pmd_hyper(ptr, val);
234 * Associate a virtual page frame with a given physical page frame
235 * and protection flags for that frame.
237 void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags)
239 set_pte_vaddr(vaddr, mfn_pte(mfn, flags));
242 static bool xen_batched_set_pte(pte_t *ptep, pte_t pteval)
246 if (paravirt_get_lazy_mode() != PARAVIRT_LAZY_MMU)
251 u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE;
252 u.val = pte_val_ma(pteval);
253 xen_extend_mmu_update(&u);
255 xen_mc_issue(PARAVIRT_LAZY_MMU);
260 static inline void __xen_set_pte(pte_t *ptep, pte_t pteval)
262 if (!xen_batched_set_pte(ptep, pteval)) {
264 * Could call native_set_pte() here and trap and
265 * emulate the PTE write but with 32-bit guests this
266 * needs two traps (one for each of the two 32-bit
267 * words in the PTE) so do one hypercall directly
272 u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE;
273 u.val = pte_val_ma(pteval);
274 HYPERVISOR_mmu_update(&u, 1, NULL, DOMID_SELF);
278 static void xen_set_pte(pte_t *ptep, pte_t pteval)
280 trace_xen_mmu_set_pte(ptep, pteval);
281 __xen_set_pte(ptep, pteval);
284 static void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
285 pte_t *ptep, pte_t pteval)
287 trace_xen_mmu_set_pte_at(mm, addr, ptep, pteval);
288 __xen_set_pte(ptep, pteval);
291 pte_t xen_ptep_modify_prot_start(struct mm_struct *mm,
292 unsigned long addr, pte_t *ptep)
294 /* Just return the pte as-is. We preserve the bits on commit */
295 trace_xen_mmu_ptep_modify_prot_start(mm, addr, ptep, *ptep);
299 void xen_ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr,
300 pte_t *ptep, pte_t pte)
304 trace_xen_mmu_ptep_modify_prot_commit(mm, addr, ptep, pte);
307 u.ptr = virt_to_machine(ptep).maddr | MMU_PT_UPDATE_PRESERVE_AD;
308 u.val = pte_val_ma(pte);
309 xen_extend_mmu_update(&u);
311 xen_mc_issue(PARAVIRT_LAZY_MMU);
314 /* Assume pteval_t is equivalent to all the other *val_t types. */
315 static pteval_t pte_mfn_to_pfn(pteval_t val)
317 if (val & _PAGE_PRESENT) {
318 unsigned long mfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
319 unsigned long pfn = mfn_to_pfn(mfn);
321 pteval_t flags = val & PTE_FLAGS_MASK;
322 if (unlikely(pfn == ~0))
323 val = flags & ~_PAGE_PRESENT;
325 val = ((pteval_t)pfn << PAGE_SHIFT) | flags;
331 static pteval_t pte_pfn_to_mfn(pteval_t val)
333 if (val & _PAGE_PRESENT) {
334 unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
335 pteval_t flags = val & PTE_FLAGS_MASK;
338 mfn = __pfn_to_mfn(pfn);
341 * If there's no mfn for the pfn, then just create an
342 * empty non-present pte. Unfortunately this loses
343 * information about the original pfn, so
344 * pte_mfn_to_pfn is asymmetric.
346 if (unlikely(mfn == INVALID_P2M_ENTRY)) {
350 mfn &= ~(FOREIGN_FRAME_BIT | IDENTITY_FRAME_BIT);
351 val = ((pteval_t)mfn << PAGE_SHIFT) | flags;
357 __visible pteval_t xen_pte_val(pte_t pte)
359 pteval_t pteval = pte.pte;
361 return pte_mfn_to_pfn(pteval);
363 PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val);
365 __visible pgdval_t xen_pgd_val(pgd_t pgd)
367 return pte_mfn_to_pfn(pgd.pgd);
369 PV_CALLEE_SAVE_REGS_THUNK(xen_pgd_val);
371 __visible pte_t xen_make_pte(pteval_t pte)
373 pte = pte_pfn_to_mfn(pte);
375 return native_make_pte(pte);
377 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte);
379 __visible pgd_t xen_make_pgd(pgdval_t pgd)
381 pgd = pte_pfn_to_mfn(pgd);
382 return native_make_pgd(pgd);
384 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pgd);
386 __visible pmdval_t xen_pmd_val(pmd_t pmd)
388 return pte_mfn_to_pfn(pmd.pmd);
390 PV_CALLEE_SAVE_REGS_THUNK(xen_pmd_val);
392 static void xen_set_pud_hyper(pud_t *ptr, pud_t val)
400 /* ptr may be ioremapped for 64-bit pagetable setup */
401 u.ptr = arbitrary_virt_to_machine(ptr).maddr;
402 u.val = pud_val_ma(val);
403 xen_extend_mmu_update(&u);
405 xen_mc_issue(PARAVIRT_LAZY_MMU);
410 static void xen_set_pud(pud_t *ptr, pud_t val)
412 trace_xen_mmu_set_pud(ptr, val);
414 /* If page is not pinned, we can just update the entry
416 if (!xen_page_pinned(ptr)) {
421 xen_set_pud_hyper(ptr, val);
424 #ifdef CONFIG_X86_PAE
425 static void xen_set_pte_atomic(pte_t *ptep, pte_t pte)
427 trace_xen_mmu_set_pte_atomic(ptep, pte);
428 set_64bit((u64 *)ptep, native_pte_val(pte));
431 static void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
433 trace_xen_mmu_pte_clear(mm, addr, ptep);
434 if (!xen_batched_set_pte(ptep, native_make_pte(0)))
435 native_pte_clear(mm, addr, ptep);
438 static void xen_pmd_clear(pmd_t *pmdp)
440 trace_xen_mmu_pmd_clear(pmdp);
441 set_pmd(pmdp, __pmd(0));
443 #endif /* CONFIG_X86_PAE */
445 __visible pmd_t xen_make_pmd(pmdval_t pmd)
447 pmd = pte_pfn_to_mfn(pmd);
448 return native_make_pmd(pmd);
450 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pmd);
452 #if CONFIG_PGTABLE_LEVELS == 4
453 __visible pudval_t xen_pud_val(pud_t pud)
455 return pte_mfn_to_pfn(pud.pud);
457 PV_CALLEE_SAVE_REGS_THUNK(xen_pud_val);
459 __visible pud_t xen_make_pud(pudval_t pud)
461 pud = pte_pfn_to_mfn(pud);
463 return native_make_pud(pud);
465 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pud);
467 static pgd_t *xen_get_user_pgd(pgd_t *pgd)
469 pgd_t *pgd_page = (pgd_t *)(((unsigned long)pgd) & PAGE_MASK);
470 unsigned offset = pgd - pgd_page;
471 pgd_t *user_ptr = NULL;
473 if (offset < pgd_index(USER_LIMIT)) {
474 struct page *page = virt_to_page(pgd_page);
475 user_ptr = (pgd_t *)page->private;
483 static void __xen_set_p4d_hyper(p4d_t *ptr, p4d_t val)
487 u.ptr = virt_to_machine(ptr).maddr;
488 u.val = p4d_val_ma(val);
489 xen_extend_mmu_update(&u);
493 * Raw hypercall-based set_p4d, intended for in early boot before
494 * there's a page structure. This implies:
495 * 1. The only existing pagetable is the kernel's
496 * 2. It is always pinned
497 * 3. It has no user pagetable attached to it
499 static void __init xen_set_p4d_hyper(p4d_t *ptr, p4d_t val)
505 __xen_set_p4d_hyper(ptr, val);
507 xen_mc_issue(PARAVIRT_LAZY_MMU);
512 static void xen_set_p4d(p4d_t *ptr, p4d_t val)
514 pgd_t *user_ptr = xen_get_user_pgd((pgd_t *)ptr);
517 trace_xen_mmu_set_p4d(ptr, (p4d_t *)user_ptr, val);
519 /* If page is not pinned, we can just update the entry
521 if (!xen_page_pinned(ptr)) {
524 WARN_ON(xen_page_pinned(user_ptr));
525 pgd_val.pgd = p4d_val_ma(val);
531 /* If it's pinned, then we can at least batch the kernel and
532 user updates together. */
535 __xen_set_p4d_hyper(ptr, val);
537 __xen_set_p4d_hyper((p4d_t *)user_ptr, val);
539 xen_mc_issue(PARAVIRT_LAZY_MMU);
541 #endif /* CONFIG_PGTABLE_LEVELS == 4 */
543 static int xen_pmd_walk(struct mm_struct *mm, pmd_t *pmd,
544 int (*func)(struct mm_struct *mm, struct page *, enum pt_level),
545 bool last, unsigned long limit)
547 int i, nr, flush = 0;
549 nr = last ? pmd_index(limit) + 1 : PTRS_PER_PMD;
550 for (i = 0; i < nr; i++) {
551 if (!pmd_none(pmd[i]))
552 flush |= (*func)(mm, pmd_page(pmd[i]), PT_PTE);
557 static int xen_pud_walk(struct mm_struct *mm, pud_t *pud,
558 int (*func)(struct mm_struct *mm, struct page *, enum pt_level),
559 bool last, unsigned long limit)
561 int i, nr, flush = 0;
563 nr = last ? pud_index(limit) + 1 : PTRS_PER_PUD;
564 for (i = 0; i < nr; i++) {
567 if (pud_none(pud[i]))
570 pmd = pmd_offset(&pud[i], 0);
571 if (PTRS_PER_PMD > 1)
572 flush |= (*func)(mm, virt_to_page(pmd), PT_PMD);
573 flush |= xen_pmd_walk(mm, pmd, func,
574 last && i == nr - 1, limit);
579 static int xen_p4d_walk(struct mm_struct *mm, p4d_t *p4d,
580 int (*func)(struct mm_struct *mm, struct page *, enum pt_level),
581 bool last, unsigned long limit)
583 int i, nr, flush = 0;
585 nr = last ? p4d_index(limit) + 1 : PTRS_PER_P4D;
586 for (i = 0; i < nr; i++) {
589 if (p4d_none(p4d[i]))
592 pud = pud_offset(&p4d[i], 0);
593 if (PTRS_PER_PUD > 1)
594 flush |= (*func)(mm, virt_to_page(pud), PT_PUD);
595 flush |= xen_pud_walk(mm, pud, func,
596 last && i == nr - 1, limit);
602 * (Yet another) pagetable walker. This one is intended for pinning a
603 * pagetable. This means that it walks a pagetable and calls the
604 * callback function on each page it finds making up the page table,
605 * at every level. It walks the entire pagetable, but it only bothers
606 * pinning pte pages which are below limit. In the normal case this
607 * will be STACK_TOP_MAX, but at boot we need to pin up to
610 * For 32-bit the important bit is that we don't pin beyond there,
611 * because then we start getting into Xen's ptes.
613 * For 64-bit, we must skip the Xen hole in the middle of the address
614 * space, just after the big x86-64 virtual hole.
616 static int __xen_pgd_walk(struct mm_struct *mm, pgd_t *pgd,
617 int (*func)(struct mm_struct *mm, struct page *,
621 int i, nr, flush = 0;
622 unsigned hole_low, hole_high;
624 /* The limit is the last byte to be touched */
626 BUG_ON(limit >= FIXADDR_TOP);
629 * 64-bit has a great big hole in the middle of the address
630 * space, which contains the Xen mappings. On 32-bit these
631 * will end up making a zero-sized hole and so is a no-op.
633 hole_low = pgd_index(USER_LIMIT);
634 hole_high = pgd_index(PAGE_OFFSET);
636 nr = pgd_index(limit) + 1;
637 for (i = 0; i < nr; i++) {
640 if (i >= hole_low && i < hole_high)
643 if (pgd_none(pgd[i]))
646 p4d = p4d_offset(&pgd[i], 0);
647 if (PTRS_PER_P4D > 1)
648 flush |= (*func)(mm, virt_to_page(p4d), PT_P4D);
649 flush |= xen_p4d_walk(mm, p4d, func, i == nr - 1, limit);
652 /* Do the top level last, so that the callbacks can use it as
653 a cue to do final things like tlb flushes. */
654 flush |= (*func)(mm, virt_to_page(pgd), PT_PGD);
659 static int xen_pgd_walk(struct mm_struct *mm,
660 int (*func)(struct mm_struct *mm, struct page *,
664 return __xen_pgd_walk(mm, mm->pgd, func, limit);
667 /* If we're using split pte locks, then take the page's lock and
668 return a pointer to it. Otherwise return NULL. */
669 static spinlock_t *xen_pte_lock(struct page *page, struct mm_struct *mm)
671 spinlock_t *ptl = NULL;
673 #if USE_SPLIT_PTE_PTLOCKS
674 ptl = ptlock_ptr(page);
675 spin_lock_nest_lock(ptl, &mm->page_table_lock);
681 static void xen_pte_unlock(void *v)
687 static void xen_do_pin(unsigned level, unsigned long pfn)
692 op.arg1.mfn = pfn_to_mfn(pfn);
694 xen_extend_mmuext_op(&op);
697 static int xen_pin_page(struct mm_struct *mm, struct page *page,
700 unsigned pgfl = TestSetPagePinned(page);
704 flush = 0; /* already pinned */
705 else if (PageHighMem(page))
706 /* kmaps need flushing if we found an unpinned
710 void *pt = lowmem_page_address(page);
711 unsigned long pfn = page_to_pfn(page);
712 struct multicall_space mcs = __xen_mc_entry(0);
718 * We need to hold the pagetable lock between the time
719 * we make the pagetable RO and when we actually pin
720 * it. If we don't, then other users may come in and
721 * attempt to update the pagetable by writing it,
722 * which will fail because the memory is RO but not
723 * pinned, so Xen won't do the trap'n'emulate.
725 * If we're using split pte locks, we can't hold the
726 * entire pagetable's worth of locks during the
727 * traverse, because we may wrap the preempt count (8
728 * bits). The solution is to mark RO and pin each PTE
729 * page while holding the lock. This means the number
730 * of locks we end up holding is never more than a
731 * batch size (~32 entries, at present).
733 * If we're not using split pte locks, we needn't pin
734 * the PTE pages independently, because we're
735 * protected by the overall pagetable lock.
739 ptl = xen_pte_lock(page, mm);
741 MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
742 pfn_pte(pfn, PAGE_KERNEL_RO),
743 level == PT_PGD ? UVMF_TLB_FLUSH : 0);
746 xen_do_pin(MMUEXT_PIN_L1_TABLE, pfn);
748 /* Queue a deferred unlock for when this batch
750 xen_mc_callback(xen_pte_unlock, ptl);
757 /* This is called just after a mm has been created, but it has not
758 been used yet. We need to make sure that its pagetable is all
759 read-only, and can be pinned. */
760 static void __xen_pgd_pin(struct mm_struct *mm, pgd_t *pgd)
762 trace_xen_mmu_pgd_pin(mm, pgd);
766 if (__xen_pgd_walk(mm, pgd, xen_pin_page, USER_LIMIT)) {
767 /* re-enable interrupts for flushing */
777 pgd_t *user_pgd = xen_get_user_pgd(pgd);
779 xen_do_pin(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(pgd)));
782 xen_pin_page(mm, virt_to_page(user_pgd), PT_PGD);
783 xen_do_pin(MMUEXT_PIN_L4_TABLE,
784 PFN_DOWN(__pa(user_pgd)));
787 #else /* CONFIG_X86_32 */
788 #ifdef CONFIG_X86_PAE
789 /* Need to make sure unshared kernel PMD is pinnable */
790 xen_pin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
793 xen_do_pin(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(pgd)));
794 #endif /* CONFIG_X86_64 */
798 static void xen_pgd_pin(struct mm_struct *mm)
800 __xen_pgd_pin(mm, mm->pgd);
804 * On save, we need to pin all pagetables to make sure they get their
805 * mfns turned into pfns. Search the list for any unpinned pgds and pin
806 * them (unpinned pgds are not currently in use, probably because the
807 * process is under construction or destruction).
809 * Expected to be called in stop_machine() ("equivalent to taking
810 * every spinlock in the system"), so the locking doesn't really
811 * matter all that much.
813 void xen_mm_pin_all(void)
817 spin_lock(&pgd_lock);
819 list_for_each_entry(page, &pgd_list, lru) {
820 if (!PagePinned(page)) {
821 __xen_pgd_pin(&init_mm, (pgd_t *)page_address(page));
822 SetPageSavePinned(page);
826 spin_unlock(&pgd_lock);
830 * The init_mm pagetable is really pinned as soon as its created, but
831 * that's before we have page structures to store the bits. So do all
832 * the book-keeping now.
834 static int __init xen_mark_pinned(struct mm_struct *mm, struct page *page,
841 static void __init xen_mark_init_mm_pinned(void)
843 xen_pgd_walk(&init_mm, xen_mark_pinned, FIXADDR_TOP);
846 static int xen_unpin_page(struct mm_struct *mm, struct page *page,
849 unsigned pgfl = TestClearPagePinned(page);
851 if (pgfl && !PageHighMem(page)) {
852 void *pt = lowmem_page_address(page);
853 unsigned long pfn = page_to_pfn(page);
854 spinlock_t *ptl = NULL;
855 struct multicall_space mcs;
858 * Do the converse to pin_page. If we're using split
859 * pte locks, we must be holding the lock for while
860 * the pte page is unpinned but still RO to prevent
861 * concurrent updates from seeing it in this
862 * partially-pinned state.
864 if (level == PT_PTE) {
865 ptl = xen_pte_lock(page, mm);
868 xen_do_pin(MMUEXT_UNPIN_TABLE, pfn);
871 mcs = __xen_mc_entry(0);
873 MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
874 pfn_pte(pfn, PAGE_KERNEL),
875 level == PT_PGD ? UVMF_TLB_FLUSH : 0);
878 /* unlock when batch completed */
879 xen_mc_callback(xen_pte_unlock, ptl);
883 return 0; /* never need to flush on unpin */
886 /* Release a pagetables pages back as normal RW */
887 static void __xen_pgd_unpin(struct mm_struct *mm, pgd_t *pgd)
889 trace_xen_mmu_pgd_unpin(mm, pgd);
893 xen_do_pin(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
897 pgd_t *user_pgd = xen_get_user_pgd(pgd);
900 xen_do_pin(MMUEXT_UNPIN_TABLE,
901 PFN_DOWN(__pa(user_pgd)));
902 xen_unpin_page(mm, virt_to_page(user_pgd), PT_PGD);
907 #ifdef CONFIG_X86_PAE
908 /* Need to make sure unshared kernel PMD is unpinned */
909 xen_unpin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
913 __xen_pgd_walk(mm, pgd, xen_unpin_page, USER_LIMIT);
918 static void xen_pgd_unpin(struct mm_struct *mm)
920 __xen_pgd_unpin(mm, mm->pgd);
924 * On resume, undo any pinning done at save, so that the rest of the
925 * kernel doesn't see any unexpected pinned pagetables.
927 void xen_mm_unpin_all(void)
931 spin_lock(&pgd_lock);
933 list_for_each_entry(page, &pgd_list, lru) {
934 if (PageSavePinned(page)) {
935 BUG_ON(!PagePinned(page));
936 __xen_pgd_unpin(&init_mm, (pgd_t *)page_address(page));
937 ClearPageSavePinned(page);
941 spin_unlock(&pgd_lock);
944 static void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
946 spin_lock(&next->page_table_lock);
948 spin_unlock(&next->page_table_lock);
951 static void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
953 spin_lock(&mm->page_table_lock);
955 spin_unlock(&mm->page_table_lock);
958 static void drop_mm_ref_this_cpu(void *info)
960 struct mm_struct *mm = info;
962 if (this_cpu_read(cpu_tlbstate.loaded_mm) == mm)
963 leave_mm(smp_processor_id());
966 * If this cpu still has a stale cr3 reference, then make sure
967 * it has been flushed.
969 if (this_cpu_read(xen_current_cr3) == __pa(mm->pgd))
975 * Another cpu may still have their %cr3 pointing at the pagetable, so
976 * we need to repoint it somewhere else before we can unpin it.
978 static void xen_drop_mm_ref(struct mm_struct *mm)
983 drop_mm_ref_this_cpu(mm);
985 /* Get the "official" set of cpus referring to our pagetable. */
986 if (!alloc_cpumask_var(&mask, GFP_ATOMIC)) {
987 for_each_online_cpu(cpu) {
988 if (per_cpu(xen_current_cr3, cpu) != __pa(mm->pgd))
990 smp_call_function_single(cpu, drop_mm_ref_this_cpu, mm, 1);
996 * It's possible that a vcpu may have a stale reference to our
997 * cr3, because its in lazy mode, and it hasn't yet flushed
998 * its set of pending hypercalls yet. In this case, we can
999 * look at its actual current cr3 value, and force it to flush
1002 cpumask_clear(mask);
1003 for_each_online_cpu(cpu) {
1004 if (per_cpu(xen_current_cr3, cpu) == __pa(mm->pgd))
1005 cpumask_set_cpu(cpu, mask);
1008 smp_call_function_many(mask, drop_mm_ref_this_cpu, mm, 1);
1009 free_cpumask_var(mask);
1012 static void xen_drop_mm_ref(struct mm_struct *mm)
1014 drop_mm_ref_this_cpu(mm);
1019 * While a process runs, Xen pins its pagetables, which means that the
1020 * hypervisor forces it to be read-only, and it controls all updates
1021 * to it. This means that all pagetable updates have to go via the
1022 * hypervisor, which is moderately expensive.
1024 * Since we're pulling the pagetable down, we switch to use init_mm,
1025 * unpin old process pagetable and mark it all read-write, which
1026 * allows further operations on it to be simple memory accesses.
1028 * The only subtle point is that another CPU may be still using the
1029 * pagetable because of lazy tlb flushing. This means we need need to
1030 * switch all CPUs off this pagetable before we can unpin it.
1032 static void xen_exit_mmap(struct mm_struct *mm)
1034 get_cpu(); /* make sure we don't move around */
1035 xen_drop_mm_ref(mm);
1038 spin_lock(&mm->page_table_lock);
1040 /* pgd may not be pinned in the error exit path of execve */
1041 if (xen_page_pinned(mm->pgd))
1044 spin_unlock(&mm->page_table_lock);
1047 static void xen_post_allocator_init(void);
1049 static void __init pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
1051 struct mmuext_op op;
1054 op.arg1.mfn = pfn_to_mfn(pfn);
1055 if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
1059 #ifdef CONFIG_X86_64
1060 static void __init xen_cleanhighmap(unsigned long vaddr,
1061 unsigned long vaddr_end)
1063 unsigned long kernel_end = roundup((unsigned long)_brk_end, PMD_SIZE) - 1;
1064 pmd_t *pmd = level2_kernel_pgt + pmd_index(vaddr);
1066 /* NOTE: The loop is more greedy than the cleanup_highmap variant.
1067 * We include the PMD passed in on _both_ boundaries. */
1068 for (; vaddr <= vaddr_end && (pmd < (level2_kernel_pgt + PTRS_PER_PMD));
1069 pmd++, vaddr += PMD_SIZE) {
1072 if (vaddr < (unsigned long) _text || vaddr > kernel_end)
1073 set_pmd(pmd, __pmd(0));
1075 /* In case we did something silly, we should crash in this function
1076 * instead of somewhere later and be confusing. */
1081 * Make a page range writeable and free it.
1083 static void __init xen_free_ro_pages(unsigned long paddr, unsigned long size)
1085 void *vaddr = __va(paddr);
1086 void *vaddr_end = vaddr + size;
1088 for (; vaddr < vaddr_end; vaddr += PAGE_SIZE)
1089 make_lowmem_page_readwrite(vaddr);
1091 memblock_free(paddr, size);
1094 static void __init xen_cleanmfnmap_free_pgtbl(void *pgtbl, bool unpin)
1096 unsigned long pa = __pa(pgtbl) & PHYSICAL_PAGE_MASK;
1099 pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(pa));
1100 ClearPagePinned(virt_to_page(__va(pa)));
1101 xen_free_ro_pages(pa, PAGE_SIZE);
1104 static void __init xen_cleanmfnmap_pmd(pmd_t *pmd, bool unpin)
1110 if (pmd_large(*pmd)) {
1111 pa = pmd_val(*pmd) & PHYSICAL_PAGE_MASK;
1112 xen_free_ro_pages(pa, PMD_SIZE);
1116 pte_tbl = pte_offset_kernel(pmd, 0);
1117 for (i = 0; i < PTRS_PER_PTE; i++) {
1118 if (pte_none(pte_tbl[i]))
1120 pa = pte_pfn(pte_tbl[i]) << PAGE_SHIFT;
1121 xen_free_ro_pages(pa, PAGE_SIZE);
1123 set_pmd(pmd, __pmd(0));
1124 xen_cleanmfnmap_free_pgtbl(pte_tbl, unpin);
1127 static void __init xen_cleanmfnmap_pud(pud_t *pud, bool unpin)
1133 if (pud_large(*pud)) {
1134 pa = pud_val(*pud) & PHYSICAL_PAGE_MASK;
1135 xen_free_ro_pages(pa, PUD_SIZE);
1139 pmd_tbl = pmd_offset(pud, 0);
1140 for (i = 0; i < PTRS_PER_PMD; i++) {
1141 if (pmd_none(pmd_tbl[i]))
1143 xen_cleanmfnmap_pmd(pmd_tbl + i, unpin);
1145 set_pud(pud, __pud(0));
1146 xen_cleanmfnmap_free_pgtbl(pmd_tbl, unpin);
1149 static void __init xen_cleanmfnmap_p4d(p4d_t *p4d, bool unpin)
1155 if (p4d_large(*p4d)) {
1156 pa = p4d_val(*p4d) & PHYSICAL_PAGE_MASK;
1157 xen_free_ro_pages(pa, P4D_SIZE);
1161 pud_tbl = pud_offset(p4d, 0);
1162 for (i = 0; i < PTRS_PER_PUD; i++) {
1163 if (pud_none(pud_tbl[i]))
1165 xen_cleanmfnmap_pud(pud_tbl + i, unpin);
1167 set_p4d(p4d, __p4d(0));
1168 xen_cleanmfnmap_free_pgtbl(pud_tbl, unpin);
1172 * Since it is well isolated we can (and since it is perhaps large we should)
1173 * also free the page tables mapping the initial P->M table.
1175 static void __init xen_cleanmfnmap(unsigned long vaddr)
1182 unpin = (vaddr == 2 * PGDIR_SIZE);
1184 pgd = pgd_offset_k(vaddr);
1185 p4d = p4d_offset(pgd, 0);
1186 for (i = 0; i < PTRS_PER_P4D; i++) {
1187 if (p4d_none(p4d[i]))
1189 xen_cleanmfnmap_p4d(p4d + i, unpin);
1191 if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
1192 set_pgd(pgd, __pgd(0));
1193 xen_cleanmfnmap_free_pgtbl(p4d, unpin);
1197 static void __init xen_pagetable_p2m_free(void)
1202 size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
1204 /* No memory or already called. */
1205 if ((unsigned long)xen_p2m_addr == xen_start_info->mfn_list)
1208 /* using __ka address and sticking INVALID_P2M_ENTRY! */
1209 memset((void *)xen_start_info->mfn_list, 0xff, size);
1211 addr = xen_start_info->mfn_list;
1213 * We could be in __ka space.
1214 * We roundup to the PMD, which means that if anybody at this stage is
1215 * using the __ka address of xen_start_info or
1216 * xen_start_info->shared_info they are in going to crash. Fortunatly
1217 * we have already revectored in xen_setup_kernel_pagetable and in
1218 * xen_setup_shared_info.
1220 size = roundup(size, PMD_SIZE);
1222 if (addr >= __START_KERNEL_map) {
1223 xen_cleanhighmap(addr, addr + size);
1224 size = PAGE_ALIGN(xen_start_info->nr_pages *
1225 sizeof(unsigned long));
1226 memblock_free(__pa(addr), size);
1228 xen_cleanmfnmap(addr);
1232 static void __init xen_pagetable_cleanhighmap(void)
1237 /* At this stage, cleanup_highmap has already cleaned __ka space
1238 * from _brk_limit way up to the max_pfn_mapped (which is the end of
1239 * the ramdisk). We continue on, erasing PMD entries that point to page
1240 * tables - do note that they are accessible at this stage via __va.
1241 * As Xen is aligning the memory end to a 4MB boundary, for good
1242 * measure we also round up to PMD_SIZE * 2 - which means that if
1243 * anybody is using __ka address to the initial boot-stack - and try
1244 * to use it - they are going to crash. The xen_start_info has been
1245 * taken care of already in xen_setup_kernel_pagetable. */
1246 addr = xen_start_info->pt_base;
1247 size = xen_start_info->nr_pt_frames * PAGE_SIZE;
1249 xen_cleanhighmap(addr, roundup(addr + size, PMD_SIZE * 2));
1250 xen_start_info->pt_base = (unsigned long)__va(__pa(xen_start_info->pt_base));
1254 static void __init xen_pagetable_p2m_setup(void)
1256 xen_vmalloc_p2m_tree();
1258 #ifdef CONFIG_X86_64
1259 xen_pagetable_p2m_free();
1261 xen_pagetable_cleanhighmap();
1263 /* And revector! Bye bye old array */
1264 xen_start_info->mfn_list = (unsigned long)xen_p2m_addr;
1267 static void __init xen_pagetable_init(void)
1270 xen_post_allocator_init();
1272 xen_pagetable_p2m_setup();
1274 /* Allocate and initialize top and mid mfn levels for p2m structure */
1275 xen_build_mfn_list_list();
1277 /* Remap memory freed due to conflicts with E820 map */
1280 xen_setup_shared_info();
1282 static void xen_write_cr2(unsigned long cr2)
1284 this_cpu_read(xen_vcpu)->arch.cr2 = cr2;
1287 static unsigned long xen_read_cr2(void)
1289 return this_cpu_read(xen_vcpu)->arch.cr2;
1292 unsigned long xen_read_cr2_direct(void)
1294 return this_cpu_read(xen_vcpu_info.arch.cr2);
1297 static void xen_flush_tlb(void)
1299 struct mmuext_op *op;
1300 struct multicall_space mcs;
1302 trace_xen_mmu_flush_tlb(0);
1306 mcs = xen_mc_entry(sizeof(*op));
1309 op->cmd = MMUEXT_TLB_FLUSH_LOCAL;
1310 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
1312 xen_mc_issue(PARAVIRT_LAZY_MMU);
1317 static void xen_flush_tlb_single(unsigned long addr)
1319 struct mmuext_op *op;
1320 struct multicall_space mcs;
1322 trace_xen_mmu_flush_tlb_single(addr);
1326 mcs = xen_mc_entry(sizeof(*op));
1328 op->cmd = MMUEXT_INVLPG_LOCAL;
1329 op->arg1.linear_addr = addr & PAGE_MASK;
1330 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
1332 xen_mc_issue(PARAVIRT_LAZY_MMU);
1337 static void xen_flush_tlb_others(const struct cpumask *cpus,
1338 const struct flush_tlb_info *info)
1341 struct mmuext_op op;
1343 DECLARE_BITMAP(mask, num_processors);
1345 DECLARE_BITMAP(mask, NR_CPUS);
1348 struct multicall_space mcs;
1350 trace_xen_mmu_flush_tlb_others(cpus, info->mm, info->start, info->end);
1352 if (cpumask_empty(cpus))
1353 return; /* nothing to do */
1355 mcs = xen_mc_entry(sizeof(*args));
1357 args->op.arg2.vcpumask = to_cpumask(args->mask);
1359 /* Remove us, and any offline CPUS. */
1360 cpumask_and(to_cpumask(args->mask), cpus, cpu_online_mask);
1361 cpumask_clear_cpu(smp_processor_id(), to_cpumask(args->mask));
1363 args->op.cmd = MMUEXT_TLB_FLUSH_MULTI;
1364 if (info->end != TLB_FLUSH_ALL &&
1365 (info->end - info->start) <= PAGE_SIZE) {
1366 args->op.cmd = MMUEXT_INVLPG_MULTI;
1367 args->op.arg1.linear_addr = info->start;
1370 MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF);
1372 xen_mc_issue(PARAVIRT_LAZY_MMU);
1375 static unsigned long xen_read_cr3(void)
1377 return this_cpu_read(xen_cr3);
1380 static void set_current_cr3(void *v)
1382 this_cpu_write(xen_current_cr3, (unsigned long)v);
1385 static void __xen_write_cr3(bool kernel, unsigned long cr3)
1387 struct mmuext_op op;
1390 trace_xen_mmu_write_cr3(kernel, cr3);
1393 mfn = pfn_to_mfn(PFN_DOWN(cr3));
1397 WARN_ON(mfn == 0 && kernel);
1399 op.cmd = kernel ? MMUEXT_NEW_BASEPTR : MMUEXT_NEW_USER_BASEPTR;
1402 xen_extend_mmuext_op(&op);
1405 this_cpu_write(xen_cr3, cr3);
1407 /* Update xen_current_cr3 once the batch has actually
1409 xen_mc_callback(set_current_cr3, (void *)cr3);
1412 static void xen_write_cr3(unsigned long cr3)
1414 BUG_ON(preemptible());
1416 xen_mc_batch(); /* disables interrupts */
1418 /* Update while interrupts are disabled, so its atomic with
1420 this_cpu_write(xen_cr3, cr3);
1422 __xen_write_cr3(true, cr3);
1424 #ifdef CONFIG_X86_64
1426 pgd_t *user_pgd = xen_get_user_pgd(__va(cr3));
1428 __xen_write_cr3(false, __pa(user_pgd));
1430 __xen_write_cr3(false, 0);
1434 xen_mc_issue(PARAVIRT_LAZY_CPU); /* interrupts restored */
1437 #ifdef CONFIG_X86_64
1439 * At the start of the day - when Xen launches a guest, it has already
1440 * built pagetables for the guest. We diligently look over them
1441 * in xen_setup_kernel_pagetable and graft as appropriate them in the
1442 * init_top_pgt and its friends. Then when we are happy we load
1443 * the new init_top_pgt - and continue on.
1445 * The generic code starts (start_kernel) and 'init_mem_mapping' sets
1446 * up the rest of the pagetables. When it has completed it loads the cr3.
1447 * N.B. that baremetal would start at 'start_kernel' (and the early
1448 * #PF handler would create bootstrap pagetables) - so we are running
1449 * with the same assumptions as what to do when write_cr3 is executed
1452 * Since there are no user-page tables at all, we have two variants
1453 * of xen_write_cr3 - the early bootup (this one), and the late one
1454 * (xen_write_cr3). The reason we have to do that is that in 64-bit
1455 * the Linux kernel and user-space are both in ring 3 while the
1456 * hypervisor is in ring 0.
1458 static void __init xen_write_cr3_init(unsigned long cr3)
1460 BUG_ON(preemptible());
1462 xen_mc_batch(); /* disables interrupts */
1464 /* Update while interrupts are disabled, so its atomic with
1466 this_cpu_write(xen_cr3, cr3);
1468 __xen_write_cr3(true, cr3);
1470 xen_mc_issue(PARAVIRT_LAZY_CPU); /* interrupts restored */
1474 static int xen_pgd_alloc(struct mm_struct *mm)
1476 pgd_t *pgd = mm->pgd;
1479 BUG_ON(PagePinned(virt_to_page(pgd)));
1481 #ifdef CONFIG_X86_64
1483 struct page *page = virt_to_page(pgd);
1486 BUG_ON(page->private != 0);
1490 user_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
1491 page->private = (unsigned long)user_pgd;
1493 if (user_pgd != NULL) {
1494 #ifdef CONFIG_X86_VSYSCALL_EMULATION
1495 user_pgd[pgd_index(VSYSCALL_ADDR)] =
1496 __pgd(__pa(level3_user_vsyscall) | _PAGE_TABLE);
1501 BUG_ON(PagePinned(virt_to_page(xen_get_user_pgd(pgd))));
1507 static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
1509 #ifdef CONFIG_X86_64
1510 pgd_t *user_pgd = xen_get_user_pgd(pgd);
1513 free_page((unsigned long)user_pgd);
1518 * Init-time set_pte while constructing initial pagetables, which
1519 * doesn't allow RO page table pages to be remapped RW.
1521 * If there is no MFN for this PFN then this page is initially
1522 * ballooned out so clear the PTE (as in decrease_reservation() in
1523 * drivers/xen/balloon.c).
1525 * Many of these PTE updates are done on unpinned and writable pages
1526 * and doing a hypercall for these is unnecessary and expensive. At
1527 * this point it is not possible to tell if a page is pinned or not,
1528 * so always write the PTE directly and rely on Xen trapping and
1529 * emulating any updates as necessary.
1531 __visible pte_t xen_make_pte_init(pteval_t pte)
1533 #ifdef CONFIG_X86_64
1537 * Pages belonging to the initial p2m list mapped outside the default
1538 * address range must be mapped read-only. This region contains the
1539 * page tables for mapping the p2m list, too, and page tables MUST be
1542 pfn = (pte & PTE_PFN_MASK) >> PAGE_SHIFT;
1543 if (xen_start_info->mfn_list < __START_KERNEL_map &&
1544 pfn >= xen_start_info->first_p2m_pfn &&
1545 pfn < xen_start_info->first_p2m_pfn + xen_start_info->nr_p2m_frames)
1548 pte = pte_pfn_to_mfn(pte);
1549 return native_make_pte(pte);
1551 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte_init);
1553 static void __init xen_set_pte_init(pte_t *ptep, pte_t pte)
1555 #ifdef CONFIG_X86_32
1556 /* If there's an existing pte, then don't allow _PAGE_RW to be set */
1557 if (pte_mfn(pte) != INVALID_P2M_ENTRY
1558 && pte_val_ma(*ptep) & _PAGE_PRESENT)
1559 pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) &
1562 native_set_pte(ptep, pte);
1565 /* Early in boot, while setting up the initial pagetable, assume
1566 everything is pinned. */
1567 static void __init xen_alloc_pte_init(struct mm_struct *mm, unsigned long pfn)
1569 #ifdef CONFIG_FLATMEM
1570 BUG_ON(mem_map); /* should only be used early */
1572 make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
1573 pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
1576 /* Used for pmd and pud */
1577 static void __init xen_alloc_pmd_init(struct mm_struct *mm, unsigned long pfn)
1579 #ifdef CONFIG_FLATMEM
1580 BUG_ON(mem_map); /* should only be used early */
1582 make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
1585 /* Early release_pte assumes that all pts are pinned, since there's
1586 only init_mm and anything attached to that is pinned. */
1587 static void __init xen_release_pte_init(unsigned long pfn)
1589 pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
1590 make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
1593 static void __init xen_release_pmd_init(unsigned long pfn)
1595 make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
1598 static inline void __pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
1600 struct multicall_space mcs;
1601 struct mmuext_op *op;
1603 mcs = __xen_mc_entry(sizeof(*op));
1606 op->arg1.mfn = pfn_to_mfn(pfn);
1608 MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
1611 static inline void __set_pfn_prot(unsigned long pfn, pgprot_t prot)
1613 struct multicall_space mcs;
1614 unsigned long addr = (unsigned long)__va(pfn << PAGE_SHIFT);
1616 mcs = __xen_mc_entry(0);
1617 MULTI_update_va_mapping(mcs.mc, (unsigned long)addr,
1618 pfn_pte(pfn, prot), 0);
1621 /* This needs to make sure the new pte page is pinned iff its being
1622 attached to a pinned pagetable. */
1623 static inline void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn,
1626 bool pinned = PagePinned(virt_to_page(mm->pgd));
1628 trace_xen_mmu_alloc_ptpage(mm, pfn, level, pinned);
1631 struct page *page = pfn_to_page(pfn);
1633 SetPagePinned(page);
1635 if (!PageHighMem(page)) {
1638 __set_pfn_prot(pfn, PAGE_KERNEL_RO);
1640 if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS)
1641 __pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
1643 xen_mc_issue(PARAVIRT_LAZY_MMU);
1645 /* make sure there are no stray mappings of
1647 kmap_flush_unused();
1652 static void xen_alloc_pte(struct mm_struct *mm, unsigned long pfn)
1654 xen_alloc_ptpage(mm, pfn, PT_PTE);
1657 static void xen_alloc_pmd(struct mm_struct *mm, unsigned long pfn)
1659 xen_alloc_ptpage(mm, pfn, PT_PMD);
1662 /* This should never happen until we're OK to use struct page */
1663 static inline void xen_release_ptpage(unsigned long pfn, unsigned level)
1665 struct page *page = pfn_to_page(pfn);
1666 bool pinned = PagePinned(page);
1668 trace_xen_mmu_release_ptpage(pfn, level, pinned);
1671 if (!PageHighMem(page)) {
1674 if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS)
1675 __pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
1677 __set_pfn_prot(pfn, PAGE_KERNEL);
1679 xen_mc_issue(PARAVIRT_LAZY_MMU);
1681 ClearPagePinned(page);
1685 static void xen_release_pte(unsigned long pfn)
1687 xen_release_ptpage(pfn, PT_PTE);
1690 static void xen_release_pmd(unsigned long pfn)
1692 xen_release_ptpage(pfn, PT_PMD);
1695 #if CONFIG_PGTABLE_LEVELS >= 4
1696 static void xen_alloc_pud(struct mm_struct *mm, unsigned long pfn)
1698 xen_alloc_ptpage(mm, pfn, PT_PUD);
1701 static void xen_release_pud(unsigned long pfn)
1703 xen_release_ptpage(pfn, PT_PUD);
1707 void __init xen_reserve_top(void)
1709 #ifdef CONFIG_X86_32
1710 unsigned long top = HYPERVISOR_VIRT_START;
1711 struct xen_platform_parameters pp;
1713 if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0)
1714 top = pp.virt_start;
1716 reserve_top_address(-top);
1717 #endif /* CONFIG_X86_32 */
1721 * Like __va(), but returns address in the kernel mapping (which is
1722 * all we have until the physical memory mapping has been set up.
1724 static void * __init __ka(phys_addr_t paddr)
1726 #ifdef CONFIG_X86_64
1727 return (void *)(paddr + __START_KERNEL_map);
1733 /* Convert a machine address to physical address */
1734 static unsigned long __init m2p(phys_addr_t maddr)
1738 maddr &= PTE_PFN_MASK;
1739 paddr = mfn_to_pfn(maddr >> PAGE_SHIFT) << PAGE_SHIFT;
1744 /* Convert a machine address to kernel virtual */
1745 static void * __init m2v(phys_addr_t maddr)
1747 return __ka(m2p(maddr));
1750 /* Set the page permissions on an identity-mapped pages */
1751 static void __init set_page_prot_flags(void *addr, pgprot_t prot,
1752 unsigned long flags)
1754 unsigned long pfn = __pa(addr) >> PAGE_SHIFT;
1755 pte_t pte = pfn_pte(pfn, prot);
1757 if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, flags))
1760 static void __init set_page_prot(void *addr, pgprot_t prot)
1762 return set_page_prot_flags(addr, prot, UVMF_NONE);
1764 #ifdef CONFIG_X86_32
1765 static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
1767 unsigned pmdidx, pteidx;
1771 level1_ident_pgt = extend_brk(sizeof(pte_t) * LEVEL1_IDENT_ENTRIES,
1776 for (pmdidx = 0; pmdidx < PTRS_PER_PMD && pfn < max_pfn; pmdidx++) {
1779 /* Reuse or allocate a page of ptes */
1780 if (pmd_present(pmd[pmdidx]))
1781 pte_page = m2v(pmd[pmdidx].pmd);
1783 /* Check for free pte pages */
1784 if (ident_pte == LEVEL1_IDENT_ENTRIES)
1787 pte_page = &level1_ident_pgt[ident_pte];
1788 ident_pte += PTRS_PER_PTE;
1790 pmd[pmdidx] = __pmd(__pa(pte_page) | _PAGE_TABLE);
1793 /* Install mappings */
1794 for (pteidx = 0; pteidx < PTRS_PER_PTE; pteidx++, pfn++) {
1797 if (pfn > max_pfn_mapped)
1798 max_pfn_mapped = pfn;
1800 if (!pte_none(pte_page[pteidx]))
1803 pte = pfn_pte(pfn, PAGE_KERNEL_EXEC);
1804 pte_page[pteidx] = pte;
1808 for (pteidx = 0; pteidx < ident_pte; pteidx += PTRS_PER_PTE)
1809 set_page_prot(&level1_ident_pgt[pteidx], PAGE_KERNEL_RO);
1811 set_page_prot(pmd, PAGE_KERNEL_RO);
1814 void __init xen_setup_machphys_mapping(void)
1816 struct xen_machphys_mapping mapping;
1818 if (HYPERVISOR_memory_op(XENMEM_machphys_mapping, &mapping) == 0) {
1819 machine_to_phys_mapping = (unsigned long *)mapping.v_start;
1820 machine_to_phys_nr = mapping.max_mfn + 1;
1822 machine_to_phys_nr = MACH2PHYS_NR_ENTRIES;
1824 #ifdef CONFIG_X86_32
1825 WARN_ON((machine_to_phys_mapping + (machine_to_phys_nr - 1))
1826 < machine_to_phys_mapping);
1830 #ifdef CONFIG_X86_64
1831 static void __init convert_pfn_mfn(void *v)
1836 /* All levels are converted the same way, so just treat them
1838 for (i = 0; i < PTRS_PER_PTE; i++)
1839 pte[i] = xen_make_pte(pte[i].pte);
1841 static void __init check_pt_base(unsigned long *pt_base, unsigned long *pt_end,
1844 if (*pt_base == PFN_DOWN(__pa(addr))) {
1845 set_page_prot_flags((void *)addr, PAGE_KERNEL, UVMF_INVLPG);
1846 clear_page((void *)addr);
1849 if (*pt_end == PFN_DOWN(__pa(addr))) {
1850 set_page_prot_flags((void *)addr, PAGE_KERNEL, UVMF_INVLPG);
1851 clear_page((void *)addr);
1856 * Set up the initial kernel pagetable.
1858 * We can construct this by grafting the Xen provided pagetable into
1859 * head_64.S's preconstructed pagetables. We copy the Xen L2's into
1860 * level2_ident_pgt, and level2_kernel_pgt. This means that only the
1861 * kernel has a physical mapping to start with - but that's enough to
1862 * get __va working. We need to fill in the rest of the physical
1863 * mapping once some sort of allocator has been set up.
1865 void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
1869 unsigned long addr[3];
1870 unsigned long pt_base, pt_end;
1873 /* max_pfn_mapped is the last pfn mapped in the initial memory
1874 * mappings. Considering that on Xen after the kernel mappings we
1875 * have the mappings of some pages that don't exist in pfn space, we
1876 * set max_pfn_mapped to the last real pfn mapped. */
1877 if (xen_start_info->mfn_list < __START_KERNEL_map)
1878 max_pfn_mapped = xen_start_info->first_p2m_pfn;
1880 max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));
1882 pt_base = PFN_DOWN(__pa(xen_start_info->pt_base));
1883 pt_end = pt_base + xen_start_info->nr_pt_frames;
1885 /* Zap identity mapping */
1886 init_top_pgt[0] = __pgd(0);
1888 /* Pre-constructed entries are in pfn, so convert to mfn */
1889 /* L4[272] -> level3_ident_pgt */
1890 /* L4[511] -> level3_kernel_pgt */
1891 convert_pfn_mfn(init_top_pgt);
1893 /* L3_i[0] -> level2_ident_pgt */
1894 convert_pfn_mfn(level3_ident_pgt);
1895 /* L3_k[510] -> level2_kernel_pgt */
1896 /* L3_k[511] -> level2_fixmap_pgt */
1897 convert_pfn_mfn(level3_kernel_pgt);
1899 /* L3_k[511][506] -> level1_fixmap_pgt */
1900 convert_pfn_mfn(level2_fixmap_pgt);
1902 /* We get [511][511] and have Xen's version of level2_kernel_pgt */
1903 l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd);
1904 l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud);
1906 addr[0] = (unsigned long)pgd;
1907 addr[1] = (unsigned long)l3;
1908 addr[2] = (unsigned long)l2;
1909 /* Graft it onto L4[272][0]. Note that we creating an aliasing problem:
1910 * Both L4[272][0] and L4[511][510] have entries that point to the same
1911 * L2 (PMD) tables. Meaning that if you modify it in __va space
1912 * it will be also modified in the __ka space! (But if you just
1913 * modify the PMD table to point to other PTE's or none, then you
1914 * are OK - which is what cleanup_highmap does) */
1915 copy_page(level2_ident_pgt, l2);
1916 /* Graft it onto L4[511][510] */
1917 copy_page(level2_kernel_pgt, l2);
1919 /* Copy the initial P->M table mappings if necessary. */
1920 i = pgd_index(xen_start_info->mfn_list);
1921 if (i && i < pgd_index(__START_KERNEL_map))
1922 init_top_pgt[i] = ((pgd_t *)xen_start_info->pt_base)[i];
1924 /* Make pagetable pieces RO */
1925 set_page_prot(init_top_pgt, PAGE_KERNEL_RO);
1926 set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO);
1927 set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO);
1928 set_page_prot(level3_user_vsyscall, PAGE_KERNEL_RO);
1929 set_page_prot(level2_ident_pgt, PAGE_KERNEL_RO);
1930 set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
1931 set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO);
1932 set_page_prot(level1_fixmap_pgt, PAGE_KERNEL_RO);
1934 /* Pin down new L4 */
1935 pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE,
1936 PFN_DOWN(__pa_symbol(init_top_pgt)));
1938 /* Unpin Xen-provided one */
1939 pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
1942 * At this stage there can be no user pgd, and no page structure to
1943 * attach it to, so make sure we just set kernel pgd.
1946 __xen_write_cr3(true, __pa(init_top_pgt));
1947 xen_mc_issue(PARAVIRT_LAZY_CPU);
1949 /* We can't that easily rip out L3 and L2, as the Xen pagetables are
1950 * set out this way: [L4], [L1], [L2], [L3], [L1], [L1] ... for
1951 * the initial domain. For guests using the toolstack, they are in:
1952 * [L4], [L3], [L2], [L1], [L1], order .. So for dom0 we can only
1953 * rip out the [L4] (pgd), but for guests we shave off three pages.
1955 for (i = 0; i < ARRAY_SIZE(addr); i++)
1956 check_pt_base(&pt_base, &pt_end, addr[i]);
1958 /* Our (by three pages) smaller Xen pagetable that we are using */
1959 xen_pt_base = PFN_PHYS(pt_base);
1960 xen_pt_size = (pt_end - pt_base) * PAGE_SIZE;
1961 memblock_reserve(xen_pt_base, xen_pt_size);
1963 /* Revector the xen_start_info */
1964 xen_start_info = (struct start_info *)__va(__pa(xen_start_info));
1968 * Read a value from a physical address.
1970 static unsigned long __init xen_read_phys_ulong(phys_addr_t addr)
1972 unsigned long *vaddr;
1975 vaddr = early_memremap_ro(addr, sizeof(val));
1977 early_memunmap(vaddr, sizeof(val));
1982 * Translate a virtual address to a physical one without relying on mapped
1983 * page tables. Don't rely on big pages being aligned in (guest) physical
1986 static phys_addr_t __init xen_early_virt_to_phys(unsigned long vaddr)
1995 pgd = native_make_pgd(xen_read_phys_ulong(pa + pgd_index(vaddr) *
1997 if (!pgd_present(pgd))
2000 pa = pgd_val(pgd) & PTE_PFN_MASK;
2001 pud = native_make_pud(xen_read_phys_ulong(pa + pud_index(vaddr) *
2003 if (!pud_present(pud))
2005 pa = pud_val(pud) & PTE_PFN_MASK;
2007 return pa + (vaddr & ~PUD_MASK);
2009 pmd = native_make_pmd(xen_read_phys_ulong(pa + pmd_index(vaddr) *
2011 if (!pmd_present(pmd))
2013 pa = pmd_val(pmd) & PTE_PFN_MASK;
2015 return pa + (vaddr & ~PMD_MASK);
2017 pte = native_make_pte(xen_read_phys_ulong(pa + pte_index(vaddr) *
2019 if (!pte_present(pte))
2021 pa = pte_pfn(pte) << PAGE_SHIFT;
2023 return pa | (vaddr & ~PAGE_MASK);
2027 * Find a new area for the hypervisor supplied p2m list and relocate the p2m to
2030 void __init xen_relocate_p2m(void)
2032 phys_addr_t size, new_area, pt_phys, pmd_phys, pud_phys, p4d_phys;
2033 unsigned long p2m_pfn, p2m_pfn_end, n_frames, pfn, pfn_end;
2034 int n_pte, n_pt, n_pmd, n_pud, n_p4d, idx_pte, idx_pt, idx_pmd, idx_pud, idx_p4d;
2040 unsigned long *new_p2m;
2043 size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
2044 n_pte = roundup(size, PAGE_SIZE) >> PAGE_SHIFT;
2045 n_pt = roundup(size, PMD_SIZE) >> PMD_SHIFT;
2046 n_pmd = roundup(size, PUD_SIZE) >> PUD_SHIFT;
2047 n_pud = roundup(size, P4D_SIZE) >> P4D_SHIFT;
2048 if (PTRS_PER_P4D > 1)
2049 n_p4d = roundup(size, PGDIR_SIZE) >> PGDIR_SHIFT;
2052 n_frames = n_pte + n_pt + n_pmd + n_pud + n_p4d;
2054 new_area = xen_find_free_area(PFN_PHYS(n_frames));
2056 xen_raw_console_write("Can't find new memory area for p2m needed due to E820 map conflict\n");
2061 * Setup the page tables for addressing the new p2m list.
2062 * We have asked the hypervisor to map the p2m list at the user address
2063 * PUD_SIZE. It may have done so, or it may have used a kernel space
2064 * address depending on the Xen version.
2065 * To avoid any possible virtual address collision, just use
2066 * 2 * PUD_SIZE for the new area.
2068 p4d_phys = new_area;
2069 pud_phys = p4d_phys + PFN_PHYS(n_p4d);
2070 pmd_phys = pud_phys + PFN_PHYS(n_pud);
2071 pt_phys = pmd_phys + PFN_PHYS(n_pmd);
2072 p2m_pfn = PFN_DOWN(pt_phys) + n_pt;
2074 pgd = __va(read_cr3_pa());
2075 new_p2m = (unsigned long *)(2 * PGDIR_SIZE);
2080 p4d = early_memremap(p4d_phys, PAGE_SIZE);
2082 n_pud = min(save_pud, PTRS_PER_P4D);
2084 for (idx_pud = 0; idx_pud < n_pud; idx_pud++) {
2085 pud = early_memremap(pud_phys, PAGE_SIZE);
2087 for (idx_pmd = 0; idx_pmd < min(n_pmd, PTRS_PER_PUD);
2089 pmd = early_memremap(pmd_phys, PAGE_SIZE);
2091 for (idx_pt = 0; idx_pt < min(n_pt, PTRS_PER_PMD);
2093 pt = early_memremap(pt_phys, PAGE_SIZE);
2096 idx_pte < min(n_pte, PTRS_PER_PTE);
2098 set_pte(pt + idx_pte,
2099 pfn_pte(p2m_pfn, PAGE_KERNEL));
2102 n_pte -= PTRS_PER_PTE;
2103 early_memunmap(pt, PAGE_SIZE);
2104 make_lowmem_page_readonly(__va(pt_phys));
2105 pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE,
2107 set_pmd(pmd + idx_pt,
2108 __pmd(_PAGE_TABLE | pt_phys));
2109 pt_phys += PAGE_SIZE;
2111 n_pt -= PTRS_PER_PMD;
2112 early_memunmap(pmd, PAGE_SIZE);
2113 make_lowmem_page_readonly(__va(pmd_phys));
2114 pin_pagetable_pfn(MMUEXT_PIN_L2_TABLE,
2115 PFN_DOWN(pmd_phys));
2116 set_pud(pud + idx_pmd, __pud(_PAGE_TABLE | pmd_phys));
2117 pmd_phys += PAGE_SIZE;
2119 n_pmd -= PTRS_PER_PUD;
2120 early_memunmap(pud, PAGE_SIZE);
2121 make_lowmem_page_readonly(__va(pud_phys));
2122 pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, PFN_DOWN(pud_phys));
2124 set_p4d(p4d + idx_pud, __p4d(_PAGE_TABLE | pud_phys));
2126 set_pgd(pgd + 2 + idx_pud, __pgd(_PAGE_TABLE | pud_phys));
2127 pud_phys += PAGE_SIZE;
2130 save_pud -= PTRS_PER_P4D;
2131 early_memunmap(p4d, PAGE_SIZE);
2132 make_lowmem_page_readonly(__va(p4d_phys));
2133 pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE, PFN_DOWN(p4d_phys));
2134 set_pgd(pgd + 2 + idx_p4d, __pgd(_PAGE_TABLE | p4d_phys));
2135 p4d_phys += PAGE_SIZE;
2137 } while (++idx_p4d < n_p4d);
2139 /* Now copy the old p2m info to the new area. */
2140 memcpy(new_p2m, xen_p2m_addr, size);
2141 xen_p2m_addr = new_p2m;
2143 /* Release the old p2m list and set new list info. */
2144 p2m_pfn = PFN_DOWN(xen_early_virt_to_phys(xen_start_info->mfn_list));
2146 p2m_pfn_end = p2m_pfn + PFN_DOWN(size);
2148 if (xen_start_info->mfn_list < __START_KERNEL_map) {
2149 pfn = xen_start_info->first_p2m_pfn;
2150 pfn_end = xen_start_info->first_p2m_pfn +
2151 xen_start_info->nr_p2m_frames;
2152 set_pgd(pgd + 1, __pgd(0));
2155 pfn_end = p2m_pfn_end;
2158 memblock_free(PFN_PHYS(pfn), PAGE_SIZE * (pfn_end - pfn));
2159 while (pfn < pfn_end) {
2160 if (pfn == p2m_pfn) {
2164 make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
2168 xen_start_info->mfn_list = (unsigned long)xen_p2m_addr;
2169 xen_start_info->first_p2m_pfn = PFN_DOWN(new_area);
2170 xen_start_info->nr_p2m_frames = n_frames;
2173 #else /* !CONFIG_X86_64 */
2174 static RESERVE_BRK_ARRAY(pmd_t, initial_kernel_pmd, PTRS_PER_PMD);
2175 static RESERVE_BRK_ARRAY(pmd_t, swapper_kernel_pmd, PTRS_PER_PMD);
2177 static void __init xen_write_cr3_init(unsigned long cr3)
2179 unsigned long pfn = PFN_DOWN(__pa(swapper_pg_dir));
2181 BUG_ON(read_cr3_pa() != __pa(initial_page_table));
2182 BUG_ON(cr3 != __pa(swapper_pg_dir));
2185 * We are switching to swapper_pg_dir for the first time (from
2186 * initial_page_table) and therefore need to mark that page
2187 * read-only and then pin it.
2189 * Xen disallows sharing of kernel PMDs for PAE
2190 * guests. Therefore we must copy the kernel PMD from
2191 * initial_page_table into a new kernel PMD to be used in
2194 swapper_kernel_pmd =
2195 extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
2196 copy_page(swapper_kernel_pmd, initial_kernel_pmd);
2197 swapper_pg_dir[KERNEL_PGD_BOUNDARY] =
2198 __pgd(__pa(swapper_kernel_pmd) | _PAGE_PRESENT);
2199 set_page_prot(swapper_kernel_pmd, PAGE_KERNEL_RO);
2201 set_page_prot(swapper_pg_dir, PAGE_KERNEL_RO);
2203 pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, pfn);
2205 pin_pagetable_pfn(MMUEXT_UNPIN_TABLE,
2206 PFN_DOWN(__pa(initial_page_table)));
2207 set_page_prot(initial_page_table, PAGE_KERNEL);
2208 set_page_prot(initial_kernel_pmd, PAGE_KERNEL);
2210 pv_mmu_ops.write_cr3 = &xen_write_cr3;
2214 * For 32 bit domains xen_start_info->pt_base is the pgd address which might be
2215 * not the first page table in the page table pool.
2216 * Iterate through the initial page tables to find the real page table base.
2218 static phys_addr_t __init xen_find_pt_base(pmd_t *pmd)
2220 phys_addr_t pt_base, paddr;
2223 pt_base = min(__pa(xen_start_info->pt_base), __pa(pmd));
2225 for (pmdidx = 0; pmdidx < PTRS_PER_PMD; pmdidx++)
2226 if (pmd_present(pmd[pmdidx]) && !pmd_large(pmd[pmdidx])) {
2227 paddr = m2p(pmd[pmdidx].pmd);
2228 pt_base = min(pt_base, paddr);
2234 void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
2238 kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
2240 xen_pt_base = xen_find_pt_base(kernel_pmd);
2241 xen_pt_size = xen_start_info->nr_pt_frames * PAGE_SIZE;
2243 initial_kernel_pmd =
2244 extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
2246 max_pfn_mapped = PFN_DOWN(xen_pt_base + xen_pt_size + 512 * 1024);
2248 copy_page(initial_kernel_pmd, kernel_pmd);
2250 xen_map_identity_early(initial_kernel_pmd, max_pfn);
2252 copy_page(initial_page_table, pgd);
2253 initial_page_table[KERNEL_PGD_BOUNDARY] =
2254 __pgd(__pa(initial_kernel_pmd) | _PAGE_PRESENT);
2256 set_page_prot(initial_kernel_pmd, PAGE_KERNEL_RO);
2257 set_page_prot(initial_page_table, PAGE_KERNEL_RO);
2258 set_page_prot(empty_zero_page, PAGE_KERNEL_RO);
2260 pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
2262 pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE,
2263 PFN_DOWN(__pa(initial_page_table)));
2264 xen_write_cr3(__pa(initial_page_table));
2266 memblock_reserve(xen_pt_base, xen_pt_size);
2268 #endif /* CONFIG_X86_64 */
2270 void __init xen_reserve_special_pages(void)
2274 memblock_reserve(__pa(xen_start_info), PAGE_SIZE);
2275 if (xen_start_info->store_mfn) {
2276 paddr = PFN_PHYS(mfn_to_pfn(xen_start_info->store_mfn));
2277 memblock_reserve(paddr, PAGE_SIZE);
2279 if (!xen_initial_domain()) {
2280 paddr = PFN_PHYS(mfn_to_pfn(xen_start_info->console.domU.mfn));
2281 memblock_reserve(paddr, PAGE_SIZE);
2285 void __init xen_pt_check_e820(void)
2287 if (xen_is_e820_reserved(xen_pt_base, xen_pt_size)) {
2288 xen_raw_console_write("Xen hypervisor allocated page table memory conflicts with E820 map\n");
2293 static unsigned char dummy_mapping[PAGE_SIZE] __page_aligned_bss;
2295 static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
2299 phys >>= PAGE_SHIFT;
2302 case FIX_BTMAP_END ... FIX_BTMAP_BEGIN:
2304 #ifdef CONFIG_X86_32
2306 # ifdef CONFIG_HIGHMEM
2307 case FIX_KMAP_BEGIN ... FIX_KMAP_END:
2309 #elif defined(CONFIG_X86_VSYSCALL_EMULATION)
2312 case FIX_TEXT_POKE0:
2313 case FIX_TEXT_POKE1:
2314 case FIX_GDT_REMAP_BEGIN ... FIX_GDT_REMAP_END:
2315 /* All local page mappings */
2316 pte = pfn_pte(phys, prot);
2319 #ifdef CONFIG_X86_LOCAL_APIC
2320 case FIX_APIC_BASE: /* maps dummy local APIC */
2321 pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
2325 #ifdef CONFIG_X86_IO_APIC
2326 case FIX_IO_APIC_BASE_0 ... FIX_IO_APIC_BASE_END:
2328 * We just don't map the IO APIC - all access is via
2329 * hypercalls. Keep the address in the pte for reference.
2331 pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
2335 case FIX_PARAVIRT_BOOTMAP:
2336 /* This is an MFN, but it isn't an IO mapping from the
2338 pte = mfn_pte(phys, prot);
2342 /* By default, set_fixmap is used for hardware mappings */
2343 pte = mfn_pte(phys, prot);
2347 __native_set_fixmap(idx, pte);
2349 #ifdef CONFIG_X86_VSYSCALL_EMULATION
2350 /* Replicate changes to map the vsyscall page into the user
2351 pagetable vsyscall mapping. */
2352 if (idx == VSYSCALL_PAGE) {
2353 unsigned long vaddr = __fix_to_virt(idx);
2354 set_pte_vaddr_pud(level3_user_vsyscall, vaddr, pte);
2359 static void __init xen_post_allocator_init(void)
2361 pv_mmu_ops.set_pte = xen_set_pte;
2362 pv_mmu_ops.set_pmd = xen_set_pmd;
2363 pv_mmu_ops.set_pud = xen_set_pud;
2364 #if CONFIG_PGTABLE_LEVELS >= 4
2365 pv_mmu_ops.set_p4d = xen_set_p4d;
2368 /* This will work as long as patching hasn't happened yet
2369 (which it hasn't) */
2370 pv_mmu_ops.alloc_pte = xen_alloc_pte;
2371 pv_mmu_ops.alloc_pmd = xen_alloc_pmd;
2372 pv_mmu_ops.release_pte = xen_release_pte;
2373 pv_mmu_ops.release_pmd = xen_release_pmd;
2374 #if CONFIG_PGTABLE_LEVELS >= 4
2375 pv_mmu_ops.alloc_pud = xen_alloc_pud;
2376 pv_mmu_ops.release_pud = xen_release_pud;
2378 pv_mmu_ops.make_pte = PV_CALLEE_SAVE(xen_make_pte);
2380 #ifdef CONFIG_X86_64
2381 pv_mmu_ops.write_cr3 = &xen_write_cr3;
2382 SetPagePinned(virt_to_page(level3_user_vsyscall));
2384 xen_mark_init_mm_pinned();
2387 static void xen_leave_lazy_mmu(void)
2391 paravirt_leave_lazy_mmu();
2395 static const struct pv_mmu_ops xen_mmu_ops __initconst = {
2396 .read_cr2 = xen_read_cr2,
2397 .write_cr2 = xen_write_cr2,
2399 .read_cr3 = xen_read_cr3,
2400 .write_cr3 = xen_write_cr3_init,
2402 .flush_tlb_user = xen_flush_tlb,
2403 .flush_tlb_kernel = xen_flush_tlb,
2404 .flush_tlb_single = xen_flush_tlb_single,
2405 .flush_tlb_others = xen_flush_tlb_others,
2407 .pgd_alloc = xen_pgd_alloc,
2408 .pgd_free = xen_pgd_free,
2410 .alloc_pte = xen_alloc_pte_init,
2411 .release_pte = xen_release_pte_init,
2412 .alloc_pmd = xen_alloc_pmd_init,
2413 .release_pmd = xen_release_pmd_init,
2415 .set_pte = xen_set_pte_init,
2416 .set_pte_at = xen_set_pte_at,
2417 .set_pmd = xen_set_pmd_hyper,
2419 .ptep_modify_prot_start = __ptep_modify_prot_start,
2420 .ptep_modify_prot_commit = __ptep_modify_prot_commit,
2422 .pte_val = PV_CALLEE_SAVE(xen_pte_val),
2423 .pgd_val = PV_CALLEE_SAVE(xen_pgd_val),
2425 .make_pte = PV_CALLEE_SAVE(xen_make_pte_init),
2426 .make_pgd = PV_CALLEE_SAVE(xen_make_pgd),
2428 #ifdef CONFIG_X86_PAE
2429 .set_pte_atomic = xen_set_pte_atomic,
2430 .pte_clear = xen_pte_clear,
2431 .pmd_clear = xen_pmd_clear,
2432 #endif /* CONFIG_X86_PAE */
2433 .set_pud = xen_set_pud_hyper,
2435 .make_pmd = PV_CALLEE_SAVE(xen_make_pmd),
2436 .pmd_val = PV_CALLEE_SAVE(xen_pmd_val),
2438 #if CONFIG_PGTABLE_LEVELS >= 4
2439 .pud_val = PV_CALLEE_SAVE(xen_pud_val),
2440 .make_pud = PV_CALLEE_SAVE(xen_make_pud),
2441 .set_p4d = xen_set_p4d_hyper,
2443 .alloc_pud = xen_alloc_pmd_init,
2444 .release_pud = xen_release_pmd_init,
2445 #endif /* CONFIG_PGTABLE_LEVELS == 4 */
2447 .activate_mm = xen_activate_mm,
2448 .dup_mmap = xen_dup_mmap,
2449 .exit_mmap = xen_exit_mmap,
2452 .enter = paravirt_enter_lazy_mmu,
2453 .leave = xen_leave_lazy_mmu,
2454 .flush = paravirt_flush_lazy_mmu,
2457 .set_fixmap = xen_set_fixmap,
2460 void __init xen_init_mmu_ops(void)
2462 x86_init.paging.pagetable_init = xen_pagetable_init;
2464 pv_mmu_ops = xen_mmu_ops;
2466 memset(dummy_mapping, 0xff, PAGE_SIZE);
2469 /* Protected by xen_reservation_lock. */
2470 #define MAX_CONTIG_ORDER 9 /* 2MB */
2471 static unsigned long discontig_frames[1<<MAX_CONTIG_ORDER];
2473 #define VOID_PTE (mfn_pte(0, __pgprot(0)))
2474 static void xen_zap_pfn_range(unsigned long vaddr, unsigned int order,
2475 unsigned long *in_frames,
2476 unsigned long *out_frames)
2479 struct multicall_space mcs;
2482 for (i = 0; i < (1UL<<order); i++, vaddr += PAGE_SIZE) {
2483 mcs = __xen_mc_entry(0);
2486 in_frames[i] = virt_to_mfn(vaddr);
2488 MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0);
2489 __set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);
2492 out_frames[i] = virt_to_pfn(vaddr);
2498 * Update the pfn-to-mfn mappings for a virtual address range, either to
2499 * point to an array of mfns, or contiguously from a single starting
2502 static void xen_remap_exchanged_ptes(unsigned long vaddr, int order,
2503 unsigned long *mfns,
2504 unsigned long first_mfn)
2511 limit = 1u << order;
2512 for (i = 0; i < limit; i++, vaddr += PAGE_SIZE) {
2513 struct multicall_space mcs;
2516 mcs = __xen_mc_entry(0);
2520 mfn = first_mfn + i;
2522 if (i < (limit - 1))
2526 flags = UVMF_INVLPG | UVMF_ALL;
2528 flags = UVMF_TLB_FLUSH | UVMF_ALL;
2531 MULTI_update_va_mapping(mcs.mc, vaddr,
2532 mfn_pte(mfn, PAGE_KERNEL), flags);
2534 set_phys_to_machine(virt_to_pfn(vaddr), mfn);
2541 * Perform the hypercall to exchange a region of our pfns to point to
2542 * memory with the required contiguous alignment. Takes the pfns as
2543 * input, and populates mfns as output.
2545 * Returns a success code indicating whether the hypervisor was able to
2546 * satisfy the request or not.
2548 static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in,
2549 unsigned long *pfns_in,
2550 unsigned long extents_out,
2551 unsigned int order_out,
2552 unsigned long *mfns_out,
2553 unsigned int address_bits)
2558 struct xen_memory_exchange exchange = {
2560 .nr_extents = extents_in,
2561 .extent_order = order_in,
2562 .extent_start = pfns_in,
2566 .nr_extents = extents_out,
2567 .extent_order = order_out,
2568 .extent_start = mfns_out,
2569 .address_bits = address_bits,
2574 BUG_ON(extents_in << order_in != extents_out << order_out);
2576 rc = HYPERVISOR_memory_op(XENMEM_exchange, &exchange);
2577 success = (exchange.nr_exchanged == extents_in);
2579 BUG_ON(!success && ((exchange.nr_exchanged != 0) || (rc == 0)));
2580 BUG_ON(success && (rc != 0));
2585 int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
2586 unsigned int address_bits,
2587 dma_addr_t *dma_handle)
2589 unsigned long *in_frames = discontig_frames, out_frame;
2590 unsigned long flags;
2592 unsigned long vstart = (unsigned long)phys_to_virt(pstart);
2595 * Currently an auto-translated guest will not perform I/O, nor will
2596 * it require PAE page directories below 4GB. Therefore any calls to
2597 * this function are redundant and can be ignored.
2600 if (unlikely(order > MAX_CONTIG_ORDER))
2603 memset((void *) vstart, 0, PAGE_SIZE << order);
2605 spin_lock_irqsave(&xen_reservation_lock, flags);
2607 /* 1. Zap current PTEs, remembering MFNs. */
2608 xen_zap_pfn_range(vstart, order, in_frames, NULL);
2610 /* 2. Get a new contiguous memory extent. */
2611 out_frame = virt_to_pfn(vstart);
2612 success = xen_exchange_memory(1UL << order, 0, in_frames,
2613 1, order, &out_frame,
2616 /* 3. Map the new extent in place of old pages. */
2618 xen_remap_exchanged_ptes(vstart, order, NULL, out_frame);
2620 xen_remap_exchanged_ptes(vstart, order, in_frames, 0);
2622 spin_unlock_irqrestore(&xen_reservation_lock, flags);
2624 *dma_handle = virt_to_machine(vstart).maddr;
2625 return success ? 0 : -ENOMEM;
2627 EXPORT_SYMBOL_GPL(xen_create_contiguous_region);
2629 void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)
2631 unsigned long *out_frames = discontig_frames, in_frame;
2632 unsigned long flags;
2634 unsigned long vstart;
2636 if (unlikely(order > MAX_CONTIG_ORDER))
2639 vstart = (unsigned long)phys_to_virt(pstart);
2640 memset((void *) vstart, 0, PAGE_SIZE << order);
2642 spin_lock_irqsave(&xen_reservation_lock, flags);
2644 /* 1. Find start MFN of contiguous extent. */
2645 in_frame = virt_to_mfn(vstart);
2647 /* 2. Zap current PTEs. */
2648 xen_zap_pfn_range(vstart, order, NULL, out_frames);
2650 /* 3. Do the exchange for non-contiguous MFNs. */
2651 success = xen_exchange_memory(1, order, &in_frame, 1UL << order,
2654 /* 4. Map new pages in place of old pages. */
2656 xen_remap_exchanged_ptes(vstart, order, out_frames, 0);
2658 xen_remap_exchanged_ptes(vstart, order, NULL, in_frame);
2660 spin_unlock_irqrestore(&xen_reservation_lock, flags);
2662 EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
2664 #ifdef CONFIG_KEXEC_CORE
2665 phys_addr_t paddr_vmcoreinfo_note(void)
2667 if (xen_pv_domain())
2668 return virt_to_machine(vmcoreinfo_note).maddr;
2670 return __pa(vmcoreinfo_note);
2672 #endif /* CONFIG_KEXEC_CORE */