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.h>
42 #include <linux/highmem.h>
43 #include <linux/debugfs.h>
44 #include <linux/bug.h>
45 #include <linux/vmalloc.h>
46 #include <linux/module.h>
47 #include <linux/gfp.h>
48 #include <linux/memblock.h>
49 #include <linux/seq_file.h>
51 #include <trace/events/xen.h>
53 #include <asm/pgtable.h>
54 #include <asm/tlbflush.h>
55 #include <asm/fixmap.h>
56 #include <asm/mmu_context.h>
57 #include <asm/setup.h>
58 #include <asm/paravirt.h>
60 #include <asm/linkage.h>
66 #include <asm/xen/hypercall.h>
67 #include <asm/xen/hypervisor.h>
71 #include <xen/interface/xen.h>
72 #include <xen/interface/hvm/hvm_op.h>
73 #include <xen/interface/version.h>
74 #include <xen/interface/memory.h>
75 #include <xen/hvc-console.h>
77 #include "multicalls.h"
82 * Protects atomic reservation decrease/increase against concurrent increases.
83 * Also protects non-atomic updates of current_pages and balloon lists.
85 DEFINE_SPINLOCK(xen_reservation_lock);
89 * Identity map, in addition to plain kernel map. This needs to be
90 * large enough to allocate page table pages to allocate the rest.
91 * Each page can map 2MB.
93 #define LEVEL1_IDENT_ENTRIES (PTRS_PER_PTE * 4)
94 static RESERVE_BRK_ARRAY(pte_t, level1_ident_pgt, LEVEL1_IDENT_ENTRIES);
97 /* l3 pud for userspace vsyscall mapping */
98 static pud_t level3_user_vsyscall[PTRS_PER_PUD] __page_aligned_bss;
99 #endif /* CONFIG_X86_64 */
102 * Note about cr3 (pagetable base) values:
104 * xen_cr3 contains the current logical cr3 value; it contains the
105 * last set cr3. This may not be the current effective cr3, because
106 * its update may be being lazily deferred. However, a vcpu looking
107 * at its own cr3 can use this value knowing that it everything will
108 * be self-consistent.
110 * xen_current_cr3 contains the actual vcpu cr3; it is set once the
111 * hypercall to set the vcpu cr3 is complete (so it may be a little
112 * out of date, but it will never be set early). If one vcpu is
113 * looking at another vcpu's cr3 value, it should use this variable.
115 DEFINE_PER_CPU(unsigned long, xen_cr3); /* cr3 stored as physaddr */
116 DEFINE_PER_CPU(unsigned long, xen_current_cr3); /* actual vcpu cr3 */
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 unsigned long arbitrary_virt_to_mfn(void *vaddr)
127 xmaddr_t maddr = arbitrary_virt_to_machine(vaddr);
129 return PFN_DOWN(maddr.maddr);
132 xmaddr_t arbitrary_virt_to_machine(void *vaddr)
134 unsigned long address = (unsigned long)vaddr;
140 * if the PFN is in the linear mapped vaddr range, we can just use
141 * the (quick) virt_to_machine() p2m lookup
143 if (virt_addr_valid(vaddr))
144 return virt_to_machine(vaddr);
146 /* otherwise we have to do a (slower) full page-table walk */
148 pte = lookup_address(address, &level);
150 offset = address & ~PAGE_MASK;
151 return XMADDR(((phys_addr_t)pte_mfn(*pte) << PAGE_SHIFT) + offset);
153 EXPORT_SYMBOL_GPL(arbitrary_virt_to_machine);
155 void make_lowmem_page_readonly(void *vaddr)
158 unsigned long address = (unsigned long)vaddr;
161 pte = lookup_address(address, &level);
163 return; /* vaddr missing */
165 ptev = pte_wrprotect(*pte);
167 if (HYPERVISOR_update_va_mapping(address, ptev, 0))
171 void make_lowmem_page_readwrite(void *vaddr)
174 unsigned long address = (unsigned long)vaddr;
177 pte = lookup_address(address, &level);
179 return; /* vaddr missing */
181 ptev = pte_mkwrite(*pte);
183 if (HYPERVISOR_update_va_mapping(address, ptev, 0))
188 static bool xen_page_pinned(void *ptr)
190 struct page *page = virt_to_page(ptr);
192 return PagePinned(page);
195 void xen_set_domain_pte(pte_t *ptep, pte_t pteval, unsigned domid)
197 struct multicall_space mcs;
198 struct mmu_update *u;
200 trace_xen_mmu_set_domain_pte(ptep, pteval, domid);
202 mcs = xen_mc_entry(sizeof(*u));
205 /* ptep might be kmapped when using 32-bit HIGHPTE */
206 u->ptr = virt_to_machine(ptep).maddr;
207 u->val = pte_val_ma(pteval);
209 MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, domid);
211 xen_mc_issue(PARAVIRT_LAZY_MMU);
213 EXPORT_SYMBOL_GPL(xen_set_domain_pte);
215 static void xen_extend_mmu_update(const struct mmu_update *update)
217 struct multicall_space mcs;
218 struct mmu_update *u;
220 mcs = xen_mc_extend_args(__HYPERVISOR_mmu_update, sizeof(*u));
222 if (mcs.mc != NULL) {
225 mcs = __xen_mc_entry(sizeof(*u));
226 MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
233 static void xen_extend_mmuext_op(const struct mmuext_op *op)
235 struct multicall_space mcs;
238 mcs = xen_mc_extend_args(__HYPERVISOR_mmuext_op, sizeof(*u));
240 if (mcs.mc != NULL) {
243 mcs = __xen_mc_entry(sizeof(*u));
244 MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
251 static void xen_set_pmd_hyper(pmd_t *ptr, pmd_t val)
259 /* ptr may be ioremapped for 64-bit pagetable setup */
260 u.ptr = arbitrary_virt_to_machine(ptr).maddr;
261 u.val = pmd_val_ma(val);
262 xen_extend_mmu_update(&u);
264 xen_mc_issue(PARAVIRT_LAZY_MMU);
269 static void xen_set_pmd(pmd_t *ptr, pmd_t val)
271 trace_xen_mmu_set_pmd(ptr, val);
273 /* If page is not pinned, we can just update the entry
275 if (!xen_page_pinned(ptr)) {
280 xen_set_pmd_hyper(ptr, val);
284 * Associate a virtual page frame with a given physical page frame
285 * and protection flags for that frame.
287 void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags)
289 set_pte_vaddr(vaddr, mfn_pte(mfn, flags));
292 static bool xen_batched_set_pte(pte_t *ptep, pte_t pteval)
296 if (paravirt_get_lazy_mode() != PARAVIRT_LAZY_MMU)
301 u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE;
302 u.val = pte_val_ma(pteval);
303 xen_extend_mmu_update(&u);
305 xen_mc_issue(PARAVIRT_LAZY_MMU);
310 static inline void __xen_set_pte(pte_t *ptep, pte_t pteval)
312 if (!xen_batched_set_pte(ptep, pteval)) {
314 * Could call native_set_pte() here and trap and
315 * emulate the PTE write but with 32-bit guests this
316 * needs two traps (one for each of the two 32-bit
317 * words in the PTE) so do one hypercall directly
322 u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE;
323 u.val = pte_val_ma(pteval);
324 HYPERVISOR_mmu_update(&u, 1, NULL, DOMID_SELF);
328 static void xen_set_pte(pte_t *ptep, pte_t pteval)
330 trace_xen_mmu_set_pte(ptep, pteval);
331 __xen_set_pte(ptep, pteval);
334 static void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
335 pte_t *ptep, pte_t pteval)
337 trace_xen_mmu_set_pte_at(mm, addr, ptep, pteval);
338 __xen_set_pte(ptep, pteval);
341 pte_t xen_ptep_modify_prot_start(struct mm_struct *mm,
342 unsigned long addr, pte_t *ptep)
344 /* Just return the pte as-is. We preserve the bits on commit */
345 trace_xen_mmu_ptep_modify_prot_start(mm, addr, ptep, *ptep);
349 void xen_ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr,
350 pte_t *ptep, pte_t pte)
354 trace_xen_mmu_ptep_modify_prot_commit(mm, addr, ptep, pte);
357 u.ptr = virt_to_machine(ptep).maddr | MMU_PT_UPDATE_PRESERVE_AD;
358 u.val = pte_val_ma(pte);
359 xen_extend_mmu_update(&u);
361 xen_mc_issue(PARAVIRT_LAZY_MMU);
364 /* Assume pteval_t is equivalent to all the other *val_t types. */
365 static pteval_t pte_mfn_to_pfn(pteval_t val)
367 if (val & _PAGE_PRESENT) {
368 unsigned long mfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
369 unsigned long pfn = mfn_to_pfn(mfn);
371 pteval_t flags = val & PTE_FLAGS_MASK;
372 if (unlikely(pfn == ~0))
373 val = flags & ~_PAGE_PRESENT;
375 val = ((pteval_t)pfn << PAGE_SHIFT) | flags;
381 static pteval_t pte_pfn_to_mfn(pteval_t val)
383 if (val & _PAGE_PRESENT) {
384 unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
385 pteval_t flags = val & PTE_FLAGS_MASK;
388 if (!xen_feature(XENFEAT_auto_translated_physmap))
389 mfn = get_phys_to_machine(pfn);
393 * If there's no mfn for the pfn, then just create an
394 * empty non-present pte. Unfortunately this loses
395 * information about the original pfn, so
396 * pte_mfn_to_pfn is asymmetric.
398 if (unlikely(mfn == INVALID_P2M_ENTRY)) {
403 * Paramount to do this test _after_ the
404 * INVALID_P2M_ENTRY as INVALID_P2M_ENTRY &
405 * IDENTITY_FRAME_BIT resolves to true.
407 mfn &= ~FOREIGN_FRAME_BIT;
408 if (mfn & IDENTITY_FRAME_BIT) {
409 mfn &= ~IDENTITY_FRAME_BIT;
410 flags |= _PAGE_IOMAP;
413 val = ((pteval_t)mfn << PAGE_SHIFT) | flags;
419 static pteval_t iomap_pte(pteval_t val)
421 if (val & _PAGE_PRESENT) {
422 unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
423 pteval_t flags = val & PTE_FLAGS_MASK;
425 /* We assume the pte frame number is a MFN, so
426 just use it as-is. */
427 val = ((pteval_t)pfn << PAGE_SHIFT) | flags;
433 static pteval_t xen_pte_val(pte_t pte)
435 pteval_t pteval = pte.pte;
437 /* If this is a WC pte, convert back from Xen WC to Linux WC */
438 if ((pteval & (_PAGE_PAT | _PAGE_PCD | _PAGE_PWT)) == _PAGE_PAT) {
439 WARN_ON(!pat_enabled);
440 pteval = (pteval & ~_PAGE_PAT) | _PAGE_PWT;
443 if (xen_initial_domain() && (pteval & _PAGE_IOMAP))
446 return pte_mfn_to_pfn(pteval);
448 PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val);
450 static pgdval_t xen_pgd_val(pgd_t pgd)
452 return pte_mfn_to_pfn(pgd.pgd);
454 PV_CALLEE_SAVE_REGS_THUNK(xen_pgd_val);
457 * Xen's PAT setup is part of its ABI, though I assume entries 6 & 7
458 * are reserved for now, to correspond to the Intel-reserved PAT
461 * We expect Linux's PAT set as follows:
463 * Idx PTE flags Linux Xen Default
470 * 6 PAT PCD UC- UC UC-
471 * 7 PAT PCD PWT UC UC UC
474 void xen_set_pat(u64 pat)
476 /* We expect Linux to use a PAT setting of
477 * UC UC- WC WB (ignoring the PAT flag) */
478 WARN_ON(pat != 0x0007010600070106ull);
481 static pte_t xen_make_pte(pteval_t pte)
483 phys_addr_t addr = (pte & PTE_PFN_MASK);
485 /* If Linux is trying to set a WC pte, then map to the Xen WC.
486 * If _PAGE_PAT is set, then it probably means it is really
487 * _PAGE_PSE, so avoid fiddling with the PAT mapping and hope
488 * things work out OK...
490 * (We should never see kernel mappings with _PAGE_PSE set,
491 * but we could see hugetlbfs mappings, I think.).
493 if (pat_enabled && !WARN_ON(pte & _PAGE_PAT)) {
494 if ((pte & (_PAGE_PCD | _PAGE_PWT)) == _PAGE_PWT)
495 pte = (pte & ~(_PAGE_PCD | _PAGE_PWT)) | _PAGE_PAT;
499 * Unprivileged domains are allowed to do IOMAPpings for
500 * PCI passthrough, but not map ISA space. The ISA
501 * mappings are just dummy local mappings to keep other
502 * parts of the kernel happy.
504 if (unlikely(pte & _PAGE_IOMAP) &&
505 (xen_initial_domain() || addr >= ISA_END_ADDRESS)) {
506 pte = iomap_pte(pte);
509 pte = pte_pfn_to_mfn(pte);
512 return native_make_pte(pte);
514 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte);
516 static pgd_t xen_make_pgd(pgdval_t pgd)
518 pgd = pte_pfn_to_mfn(pgd);
519 return native_make_pgd(pgd);
521 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pgd);
523 static pmdval_t xen_pmd_val(pmd_t pmd)
525 return pte_mfn_to_pfn(pmd.pmd);
527 PV_CALLEE_SAVE_REGS_THUNK(xen_pmd_val);
529 static void xen_set_pud_hyper(pud_t *ptr, pud_t val)
537 /* ptr may be ioremapped for 64-bit pagetable setup */
538 u.ptr = arbitrary_virt_to_machine(ptr).maddr;
539 u.val = pud_val_ma(val);
540 xen_extend_mmu_update(&u);
542 xen_mc_issue(PARAVIRT_LAZY_MMU);
547 static void xen_set_pud(pud_t *ptr, pud_t val)
549 trace_xen_mmu_set_pud(ptr, val);
551 /* If page is not pinned, we can just update the entry
553 if (!xen_page_pinned(ptr)) {
558 xen_set_pud_hyper(ptr, val);
561 #ifdef CONFIG_X86_PAE
562 static void xen_set_pte_atomic(pte_t *ptep, pte_t pte)
564 trace_xen_mmu_set_pte_atomic(ptep, pte);
565 set_64bit((u64 *)ptep, native_pte_val(pte));
568 static void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
570 trace_xen_mmu_pte_clear(mm, addr, ptep);
571 if (!xen_batched_set_pte(ptep, native_make_pte(0)))
572 native_pte_clear(mm, addr, ptep);
575 static void xen_pmd_clear(pmd_t *pmdp)
577 trace_xen_mmu_pmd_clear(pmdp);
578 set_pmd(pmdp, __pmd(0));
580 #endif /* CONFIG_X86_PAE */
582 static pmd_t xen_make_pmd(pmdval_t pmd)
584 pmd = pte_pfn_to_mfn(pmd);
585 return native_make_pmd(pmd);
587 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pmd);
589 #if PAGETABLE_LEVELS == 4
590 static pudval_t xen_pud_val(pud_t pud)
592 return pte_mfn_to_pfn(pud.pud);
594 PV_CALLEE_SAVE_REGS_THUNK(xen_pud_val);
596 static pud_t xen_make_pud(pudval_t pud)
598 pud = pte_pfn_to_mfn(pud);
600 return native_make_pud(pud);
602 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pud);
604 static pgd_t *xen_get_user_pgd(pgd_t *pgd)
606 pgd_t *pgd_page = (pgd_t *)(((unsigned long)pgd) & PAGE_MASK);
607 unsigned offset = pgd - pgd_page;
608 pgd_t *user_ptr = NULL;
610 if (offset < pgd_index(USER_LIMIT)) {
611 struct page *page = virt_to_page(pgd_page);
612 user_ptr = (pgd_t *)page->private;
620 static void __xen_set_pgd_hyper(pgd_t *ptr, pgd_t val)
624 u.ptr = virt_to_machine(ptr).maddr;
625 u.val = pgd_val_ma(val);
626 xen_extend_mmu_update(&u);
630 * Raw hypercall-based set_pgd, intended for in early boot before
631 * there's a page structure. This implies:
632 * 1. The only existing pagetable is the kernel's
633 * 2. It is always pinned
634 * 3. It has no user pagetable attached to it
636 static void __init xen_set_pgd_hyper(pgd_t *ptr, pgd_t val)
642 __xen_set_pgd_hyper(ptr, val);
644 xen_mc_issue(PARAVIRT_LAZY_MMU);
649 static void xen_set_pgd(pgd_t *ptr, pgd_t val)
651 pgd_t *user_ptr = xen_get_user_pgd(ptr);
653 trace_xen_mmu_set_pgd(ptr, user_ptr, val);
655 /* If page is not pinned, we can just update the entry
657 if (!xen_page_pinned(ptr)) {
660 WARN_ON(xen_page_pinned(user_ptr));
666 /* If it's pinned, then we can at least batch the kernel and
667 user updates together. */
670 __xen_set_pgd_hyper(ptr, val);
672 __xen_set_pgd_hyper(user_ptr, val);
674 xen_mc_issue(PARAVIRT_LAZY_MMU);
676 #endif /* PAGETABLE_LEVELS == 4 */
679 * (Yet another) pagetable walker. This one is intended for pinning a
680 * pagetable. This means that it walks a pagetable and calls the
681 * callback function on each page it finds making up the page table,
682 * at every level. It walks the entire pagetable, but it only bothers
683 * pinning pte pages which are below limit. In the normal case this
684 * will be STACK_TOP_MAX, but at boot we need to pin up to
687 * For 32-bit the important bit is that we don't pin beyond there,
688 * because then we start getting into Xen's ptes.
690 * For 64-bit, we must skip the Xen hole in the middle of the address
691 * space, just after the big x86-64 virtual hole.
693 static int __xen_pgd_walk(struct mm_struct *mm, pgd_t *pgd,
694 int (*func)(struct mm_struct *mm, struct page *,
699 unsigned hole_low, hole_high;
700 unsigned pgdidx_limit, pudidx_limit, pmdidx_limit;
701 unsigned pgdidx, pudidx, pmdidx;
703 /* The limit is the last byte to be touched */
705 BUG_ON(limit >= FIXADDR_TOP);
707 if (xen_feature(XENFEAT_auto_translated_physmap))
711 * 64-bit has a great big hole in the middle of the address
712 * space, which contains the Xen mappings. On 32-bit these
713 * will end up making a zero-sized hole and so is a no-op.
715 hole_low = pgd_index(USER_LIMIT);
716 hole_high = pgd_index(PAGE_OFFSET);
718 pgdidx_limit = pgd_index(limit);
720 pudidx_limit = pud_index(limit);
725 pmdidx_limit = pmd_index(limit);
730 for (pgdidx = 0; pgdidx <= pgdidx_limit; pgdidx++) {
733 if (pgdidx >= hole_low && pgdidx < hole_high)
736 if (!pgd_val(pgd[pgdidx]))
739 pud = pud_offset(&pgd[pgdidx], 0);
741 if (PTRS_PER_PUD > 1) /* not folded */
742 flush |= (*func)(mm, virt_to_page(pud), PT_PUD);
744 for (pudidx = 0; pudidx < PTRS_PER_PUD; pudidx++) {
747 if (pgdidx == pgdidx_limit &&
748 pudidx > pudidx_limit)
751 if (pud_none(pud[pudidx]))
754 pmd = pmd_offset(&pud[pudidx], 0);
756 if (PTRS_PER_PMD > 1) /* not folded */
757 flush |= (*func)(mm, virt_to_page(pmd), PT_PMD);
759 for (pmdidx = 0; pmdidx < PTRS_PER_PMD; pmdidx++) {
762 if (pgdidx == pgdidx_limit &&
763 pudidx == pudidx_limit &&
764 pmdidx > pmdidx_limit)
767 if (pmd_none(pmd[pmdidx]))
770 pte = pmd_page(pmd[pmdidx]);
771 flush |= (*func)(mm, pte, PT_PTE);
777 /* Do the top level last, so that the callbacks can use it as
778 a cue to do final things like tlb flushes. */
779 flush |= (*func)(mm, virt_to_page(pgd), PT_PGD);
784 static int xen_pgd_walk(struct mm_struct *mm,
785 int (*func)(struct mm_struct *mm, struct page *,
789 return __xen_pgd_walk(mm, mm->pgd, func, limit);
792 /* If we're using split pte locks, then take the page's lock and
793 return a pointer to it. Otherwise return NULL. */
794 static spinlock_t *xen_pte_lock(struct page *page, struct mm_struct *mm)
796 spinlock_t *ptl = NULL;
798 #if USE_SPLIT_PTLOCKS
799 ptl = __pte_lockptr(page);
800 spin_lock_nest_lock(ptl, &mm->page_table_lock);
806 static void xen_pte_unlock(void *v)
812 static void xen_do_pin(unsigned level, unsigned long pfn)
817 op.arg1.mfn = pfn_to_mfn(pfn);
819 xen_extend_mmuext_op(&op);
822 static int xen_pin_page(struct mm_struct *mm, struct page *page,
825 unsigned pgfl = TestSetPagePinned(page);
829 flush = 0; /* already pinned */
830 else if (PageHighMem(page))
831 /* kmaps need flushing if we found an unpinned
835 void *pt = lowmem_page_address(page);
836 unsigned long pfn = page_to_pfn(page);
837 struct multicall_space mcs = __xen_mc_entry(0);
843 * We need to hold the pagetable lock between the time
844 * we make the pagetable RO and when we actually pin
845 * it. If we don't, then other users may come in and
846 * attempt to update the pagetable by writing it,
847 * which will fail because the memory is RO but not
848 * pinned, so Xen won't do the trap'n'emulate.
850 * If we're using split pte locks, we can't hold the
851 * entire pagetable's worth of locks during the
852 * traverse, because we may wrap the preempt count (8
853 * bits). The solution is to mark RO and pin each PTE
854 * page while holding the lock. This means the number
855 * of locks we end up holding is never more than a
856 * batch size (~32 entries, at present).
858 * If we're not using split pte locks, we needn't pin
859 * the PTE pages independently, because we're
860 * protected by the overall pagetable lock.
864 ptl = xen_pte_lock(page, mm);
866 MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
867 pfn_pte(pfn, PAGE_KERNEL_RO),
868 level == PT_PGD ? UVMF_TLB_FLUSH : 0);
871 xen_do_pin(MMUEXT_PIN_L1_TABLE, pfn);
873 /* Queue a deferred unlock for when this batch
875 xen_mc_callback(xen_pte_unlock, ptl);
882 /* This is called just after a mm has been created, but it has not
883 been used yet. We need to make sure that its pagetable is all
884 read-only, and can be pinned. */
885 static void __xen_pgd_pin(struct mm_struct *mm, pgd_t *pgd)
887 trace_xen_mmu_pgd_pin(mm, pgd);
891 if (__xen_pgd_walk(mm, pgd, xen_pin_page, USER_LIMIT)) {
892 /* re-enable interrupts for flushing */
902 pgd_t *user_pgd = xen_get_user_pgd(pgd);
904 xen_do_pin(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(pgd)));
907 xen_pin_page(mm, virt_to_page(user_pgd), PT_PGD);
908 xen_do_pin(MMUEXT_PIN_L4_TABLE,
909 PFN_DOWN(__pa(user_pgd)));
912 #else /* CONFIG_X86_32 */
913 #ifdef CONFIG_X86_PAE
914 /* Need to make sure unshared kernel PMD is pinnable */
915 xen_pin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
918 xen_do_pin(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(pgd)));
919 #endif /* CONFIG_X86_64 */
923 static void xen_pgd_pin(struct mm_struct *mm)
925 __xen_pgd_pin(mm, mm->pgd);
929 * On save, we need to pin all pagetables to make sure they get their
930 * mfns turned into pfns. Search the list for any unpinned pgds and pin
931 * them (unpinned pgds are not currently in use, probably because the
932 * process is under construction or destruction).
934 * Expected to be called in stop_machine() ("equivalent to taking
935 * every spinlock in the system"), so the locking doesn't really
936 * matter all that much.
938 void xen_mm_pin_all(void)
942 spin_lock(&pgd_lock);
944 list_for_each_entry(page, &pgd_list, lru) {
945 if (!PagePinned(page)) {
946 __xen_pgd_pin(&init_mm, (pgd_t *)page_address(page));
947 SetPageSavePinned(page);
951 spin_unlock(&pgd_lock);
955 * The init_mm pagetable is really pinned as soon as its created, but
956 * that's before we have page structures to store the bits. So do all
957 * the book-keeping now.
959 static int __init xen_mark_pinned(struct mm_struct *mm, struct page *page,
966 static void __init xen_mark_init_mm_pinned(void)
968 xen_pgd_walk(&init_mm, xen_mark_pinned, FIXADDR_TOP);
971 static int xen_unpin_page(struct mm_struct *mm, struct page *page,
974 unsigned pgfl = TestClearPagePinned(page);
976 if (pgfl && !PageHighMem(page)) {
977 void *pt = lowmem_page_address(page);
978 unsigned long pfn = page_to_pfn(page);
979 spinlock_t *ptl = NULL;
980 struct multicall_space mcs;
983 * Do the converse to pin_page. If we're using split
984 * pte locks, we must be holding the lock for while
985 * the pte page is unpinned but still RO to prevent
986 * concurrent updates from seeing it in this
987 * partially-pinned state.
989 if (level == PT_PTE) {
990 ptl = xen_pte_lock(page, mm);
993 xen_do_pin(MMUEXT_UNPIN_TABLE, pfn);
996 mcs = __xen_mc_entry(0);
998 MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
999 pfn_pte(pfn, PAGE_KERNEL),
1000 level == PT_PGD ? UVMF_TLB_FLUSH : 0);
1003 /* unlock when batch completed */
1004 xen_mc_callback(xen_pte_unlock, ptl);
1008 return 0; /* never need to flush on unpin */
1011 /* Release a pagetables pages back as normal RW */
1012 static void __xen_pgd_unpin(struct mm_struct *mm, pgd_t *pgd)
1014 trace_xen_mmu_pgd_unpin(mm, pgd);
1018 xen_do_pin(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
1020 #ifdef CONFIG_X86_64
1022 pgd_t *user_pgd = xen_get_user_pgd(pgd);
1025 xen_do_pin(MMUEXT_UNPIN_TABLE,
1026 PFN_DOWN(__pa(user_pgd)));
1027 xen_unpin_page(mm, virt_to_page(user_pgd), PT_PGD);
1032 #ifdef CONFIG_X86_PAE
1033 /* Need to make sure unshared kernel PMD is unpinned */
1034 xen_unpin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
1038 __xen_pgd_walk(mm, pgd, xen_unpin_page, USER_LIMIT);
1043 static void xen_pgd_unpin(struct mm_struct *mm)
1045 __xen_pgd_unpin(mm, mm->pgd);
1049 * On resume, undo any pinning done at save, so that the rest of the
1050 * kernel doesn't see any unexpected pinned pagetables.
1052 void xen_mm_unpin_all(void)
1056 spin_lock(&pgd_lock);
1058 list_for_each_entry(page, &pgd_list, lru) {
1059 if (PageSavePinned(page)) {
1060 BUG_ON(!PagePinned(page));
1061 __xen_pgd_unpin(&init_mm, (pgd_t *)page_address(page));
1062 ClearPageSavePinned(page);
1066 spin_unlock(&pgd_lock);
1069 static void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
1071 spin_lock(&next->page_table_lock);
1073 spin_unlock(&next->page_table_lock);
1076 static void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
1078 spin_lock(&mm->page_table_lock);
1080 spin_unlock(&mm->page_table_lock);
1085 /* Another cpu may still have their %cr3 pointing at the pagetable, so
1086 we need to repoint it somewhere else before we can unpin it. */
1087 static void drop_other_mm_ref(void *info)
1089 struct mm_struct *mm = info;
1090 struct mm_struct *active_mm;
1092 active_mm = this_cpu_read(cpu_tlbstate.active_mm);
1094 if (active_mm == mm && this_cpu_read(cpu_tlbstate.state) != TLBSTATE_OK)
1095 leave_mm(smp_processor_id());
1097 /* If this cpu still has a stale cr3 reference, then make sure
1098 it has been flushed. */
1099 if (this_cpu_read(xen_current_cr3) == __pa(mm->pgd))
1100 load_cr3(swapper_pg_dir);
1103 static void xen_drop_mm_ref(struct mm_struct *mm)
1108 if (current->active_mm == mm) {
1109 if (current->mm == mm)
1110 load_cr3(swapper_pg_dir);
1112 leave_mm(smp_processor_id());
1115 /* Get the "official" set of cpus referring to our pagetable. */
1116 if (!alloc_cpumask_var(&mask, GFP_ATOMIC)) {
1117 for_each_online_cpu(cpu) {
1118 if (!cpumask_test_cpu(cpu, mm_cpumask(mm))
1119 && per_cpu(xen_current_cr3, cpu) != __pa(mm->pgd))
1121 smp_call_function_single(cpu, drop_other_mm_ref, mm, 1);
1125 cpumask_copy(mask, mm_cpumask(mm));
1127 /* It's possible that a vcpu may have a stale reference to our
1128 cr3, because its in lazy mode, and it hasn't yet flushed
1129 its set of pending hypercalls yet. In this case, we can
1130 look at its actual current cr3 value, and force it to flush
1132 for_each_online_cpu(cpu) {
1133 if (per_cpu(xen_current_cr3, cpu) == __pa(mm->pgd))
1134 cpumask_set_cpu(cpu, mask);
1137 if (!cpumask_empty(mask))
1138 smp_call_function_many(mask, drop_other_mm_ref, mm, 1);
1139 free_cpumask_var(mask);
1142 static void xen_drop_mm_ref(struct mm_struct *mm)
1144 if (current->active_mm == mm)
1145 load_cr3(swapper_pg_dir);
1150 * While a process runs, Xen pins its pagetables, which means that the
1151 * hypervisor forces it to be read-only, and it controls all updates
1152 * to it. This means that all pagetable updates have to go via the
1153 * hypervisor, which is moderately expensive.
1155 * Since we're pulling the pagetable down, we switch to use init_mm,
1156 * unpin old process pagetable and mark it all read-write, which
1157 * allows further operations on it to be simple memory accesses.
1159 * The only subtle point is that another CPU may be still using the
1160 * pagetable because of lazy tlb flushing. This means we need need to
1161 * switch all CPUs off this pagetable before we can unpin it.
1163 static void xen_exit_mmap(struct mm_struct *mm)
1165 get_cpu(); /* make sure we don't move around */
1166 xen_drop_mm_ref(mm);
1169 spin_lock(&mm->page_table_lock);
1171 /* pgd may not be pinned in the error exit path of execve */
1172 if (xen_page_pinned(mm->pgd))
1175 spin_unlock(&mm->page_table_lock);
1178 static void xen_post_allocator_init(void);
1180 static __init void xen_mapping_pagetable_reserve(u64 start, u64 end)
1182 /* reserve the range used */
1183 native_pagetable_reserve(start, end);
1185 /* set as RW the rest */
1186 printk(KERN_DEBUG "xen: setting RW the range %llx - %llx\n", end,
1187 PFN_PHYS(pgt_buf_top));
1188 while (end < PFN_PHYS(pgt_buf_top)) {
1189 make_lowmem_page_readwrite(__va(end));
1194 #ifdef CONFIG_X86_64
1195 static void __init xen_cleanhighmap(unsigned long vaddr,
1196 unsigned long vaddr_end)
1198 unsigned long kernel_end = roundup((unsigned long)_brk_end, PMD_SIZE) - 1;
1199 pmd_t *pmd = level2_kernel_pgt + pmd_index(vaddr);
1201 /* NOTE: The loop is more greedy than the cleanup_highmap variant.
1202 * We include the PMD passed in on _both_ boundaries. */
1203 for (; vaddr <= vaddr_end && (pmd < (level2_kernel_pgt + PAGE_SIZE));
1204 pmd++, vaddr += PMD_SIZE) {
1207 if (vaddr < (unsigned long) _text || vaddr > kernel_end)
1208 set_pmd(pmd, __pmd(0));
1210 /* In case we did something silly, we should crash in this function
1211 * instead of somewhere later and be confusing. */
1215 static void __init xen_pagetable_init(void)
1217 #ifdef CONFIG_X86_64
1222 xen_setup_shared_info();
1223 #ifdef CONFIG_X86_64
1224 if (!xen_feature(XENFEAT_auto_translated_physmap)) {
1225 unsigned long new_mfn_list;
1227 size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
1229 /* On 32-bit, we get zero so this never gets executed. */
1230 new_mfn_list = xen_revector_p2m_tree();
1231 if (new_mfn_list && new_mfn_list != xen_start_info->mfn_list) {
1232 /* using __ka address and sticking INVALID_P2M_ENTRY! */
1233 memset((void *)xen_start_info->mfn_list, 0xff, size);
1235 /* We should be in __ka space. */
1236 BUG_ON(xen_start_info->mfn_list < __START_KERNEL_map);
1237 addr = xen_start_info->mfn_list;
1238 /* We roundup to the PMD, which means that if anybody at this stage is
1239 * using the __ka address of xen_start_info or xen_start_info->shared_info
1240 * they are in going to crash. Fortunatly we have already revectored
1241 * in xen_setup_kernel_pagetable and in xen_setup_shared_info. */
1242 size = roundup(size, PMD_SIZE);
1243 xen_cleanhighmap(addr, addr + size);
1245 size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
1246 memblock_free(__pa(xen_start_info->mfn_list), size);
1247 /* And revector! Bye bye old array */
1248 xen_start_info->mfn_list = new_mfn_list;
1252 /* At this stage, cleanup_highmap has already cleaned __ka space
1253 * from _brk_limit way up to the max_pfn_mapped (which is the end of
1254 * the ramdisk). We continue on, erasing PMD entries that point to page
1255 * tables - do note that they are accessible at this stage via __va.
1256 * For good measure we also round up to the PMD - which means that if
1257 * anybody is using __ka address to the initial boot-stack - and try
1258 * to use it - they are going to crash. The xen_start_info has been
1259 * taken care of already in xen_setup_kernel_pagetable. */
1260 addr = xen_start_info->pt_base;
1261 size = roundup(xen_start_info->nr_pt_frames * PAGE_SIZE, PMD_SIZE);
1263 xen_cleanhighmap(addr, addr + size);
1264 xen_start_info->pt_base = (unsigned long)__va(__pa(xen_start_info->pt_base));
1266 /* This is superflous and is not neccessary, but you know what
1267 * lets do it. The MODULES_VADDR -> MODULES_END should be clear of
1268 * anything at this stage. */
1269 xen_cleanhighmap(MODULES_VADDR, roundup(MODULES_VADDR, PUD_SIZE) - 1);
1273 xen_post_allocator_init();
1275 static void xen_write_cr2(unsigned long cr2)
1277 this_cpu_read(xen_vcpu)->arch.cr2 = cr2;
1280 static unsigned long xen_read_cr2(void)
1282 return this_cpu_read(xen_vcpu)->arch.cr2;
1285 unsigned long xen_read_cr2_direct(void)
1287 return this_cpu_read(xen_vcpu_info.arch.cr2);
1290 static void xen_flush_tlb(void)
1292 struct mmuext_op *op;
1293 struct multicall_space mcs;
1295 trace_xen_mmu_flush_tlb(0);
1299 mcs = xen_mc_entry(sizeof(*op));
1302 op->cmd = MMUEXT_TLB_FLUSH_LOCAL;
1303 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
1305 xen_mc_issue(PARAVIRT_LAZY_MMU);
1310 static void xen_flush_tlb_single(unsigned long addr)
1312 struct mmuext_op *op;
1313 struct multicall_space mcs;
1315 trace_xen_mmu_flush_tlb_single(addr);
1319 mcs = xen_mc_entry(sizeof(*op));
1321 op->cmd = MMUEXT_INVLPG_LOCAL;
1322 op->arg1.linear_addr = addr & PAGE_MASK;
1323 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
1325 xen_mc_issue(PARAVIRT_LAZY_MMU);
1330 static void xen_flush_tlb_others(const struct cpumask *cpus,
1331 struct mm_struct *mm, unsigned long start,
1335 struct mmuext_op op;
1337 DECLARE_BITMAP(mask, num_processors);
1339 DECLARE_BITMAP(mask, NR_CPUS);
1342 struct multicall_space mcs;
1344 trace_xen_mmu_flush_tlb_others(cpus, mm, start, end);
1346 if (cpumask_empty(cpus))
1347 return; /* nothing to do */
1349 mcs = xen_mc_entry(sizeof(*args));
1351 args->op.arg2.vcpumask = to_cpumask(args->mask);
1353 /* Remove us, and any offline CPUS. */
1354 cpumask_and(to_cpumask(args->mask), cpus, cpu_online_mask);
1355 cpumask_clear_cpu(smp_processor_id(), to_cpumask(args->mask));
1357 args->op.cmd = MMUEXT_TLB_FLUSH_MULTI;
1358 if (end != TLB_FLUSH_ALL && (end - start) <= PAGE_SIZE) {
1359 args->op.cmd = MMUEXT_INVLPG_MULTI;
1360 args->op.arg1.linear_addr = start;
1363 MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF);
1365 xen_mc_issue(PARAVIRT_LAZY_MMU);
1368 static unsigned long xen_read_cr3(void)
1370 return this_cpu_read(xen_cr3);
1373 static void set_current_cr3(void *v)
1375 this_cpu_write(xen_current_cr3, (unsigned long)v);
1378 static void __xen_write_cr3(bool kernel, unsigned long cr3)
1380 struct mmuext_op op;
1383 trace_xen_mmu_write_cr3(kernel, cr3);
1386 mfn = pfn_to_mfn(PFN_DOWN(cr3));
1390 WARN_ON(mfn == 0 && kernel);
1392 op.cmd = kernel ? MMUEXT_NEW_BASEPTR : MMUEXT_NEW_USER_BASEPTR;
1395 xen_extend_mmuext_op(&op);
1398 this_cpu_write(xen_cr3, cr3);
1400 /* Update xen_current_cr3 once the batch has actually
1402 xen_mc_callback(set_current_cr3, (void *)cr3);
1406 static void xen_write_cr3(unsigned long cr3)
1408 BUG_ON(preemptible());
1410 xen_mc_batch(); /* disables interrupts */
1412 /* Update while interrupts are disabled, so its atomic with
1414 this_cpu_write(xen_cr3, cr3);
1416 __xen_write_cr3(true, cr3);
1418 #ifdef CONFIG_X86_64
1420 pgd_t *user_pgd = xen_get_user_pgd(__va(cr3));
1422 __xen_write_cr3(false, __pa(user_pgd));
1424 __xen_write_cr3(false, 0);
1428 xen_mc_issue(PARAVIRT_LAZY_CPU); /* interrupts restored */
1431 static int xen_pgd_alloc(struct mm_struct *mm)
1433 pgd_t *pgd = mm->pgd;
1436 BUG_ON(PagePinned(virt_to_page(pgd)));
1438 #ifdef CONFIG_X86_64
1440 struct page *page = virt_to_page(pgd);
1443 BUG_ON(page->private != 0);
1447 user_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
1448 page->private = (unsigned long)user_pgd;
1450 if (user_pgd != NULL) {
1451 user_pgd[pgd_index(VSYSCALL_START)] =
1452 __pgd(__pa(level3_user_vsyscall) | _PAGE_TABLE);
1456 BUG_ON(PagePinned(virt_to_page(xen_get_user_pgd(pgd))));
1463 static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
1465 #ifdef CONFIG_X86_64
1466 pgd_t *user_pgd = xen_get_user_pgd(pgd);
1469 free_page((unsigned long)user_pgd);
1473 #ifdef CONFIG_X86_32
1474 static pte_t __init mask_rw_pte(pte_t *ptep, pte_t pte)
1476 /* If there's an existing pte, then don't allow _PAGE_RW to be set */
1477 if (pte_val_ma(*ptep) & _PAGE_PRESENT)
1478 pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) &
1483 #else /* CONFIG_X86_64 */
1484 static pte_t __init mask_rw_pte(pte_t *ptep, pte_t pte)
1486 unsigned long pfn = pte_pfn(pte);
1489 * If the new pfn is within the range of the newly allocated
1490 * kernel pagetable, and it isn't being mapped into an
1491 * early_ioremap fixmap slot as a freshly allocated page, make sure
1494 if (((!is_early_ioremap_ptep(ptep) &&
1495 pfn >= pgt_buf_start && pfn < pgt_buf_top)) ||
1496 (is_early_ioremap_ptep(ptep) && pfn != (pgt_buf_end - 1)))
1497 pte = pte_wrprotect(pte);
1501 #endif /* CONFIG_X86_64 */
1504 * Init-time set_pte while constructing initial pagetables, which
1505 * doesn't allow RO page table pages to be remapped RW.
1507 * If there is no MFN for this PFN then this page is initially
1508 * ballooned out so clear the PTE (as in decrease_reservation() in
1509 * drivers/xen/balloon.c).
1511 * Many of these PTE updates are done on unpinned and writable pages
1512 * and doing a hypercall for these is unnecessary and expensive. At
1513 * this point it is not possible to tell if a page is pinned or not,
1514 * so always write the PTE directly and rely on Xen trapping and
1515 * emulating any updates as necessary.
1517 static void __init xen_set_pte_init(pte_t *ptep, pte_t pte)
1519 if (pte_mfn(pte) != INVALID_P2M_ENTRY)
1520 pte = mask_rw_pte(ptep, pte);
1524 native_set_pte(ptep, pte);
1527 static void pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
1529 struct mmuext_op op;
1531 op.arg1.mfn = pfn_to_mfn(pfn);
1532 if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
1536 /* Early in boot, while setting up the initial pagetable, assume
1537 everything is pinned. */
1538 static void __init xen_alloc_pte_init(struct mm_struct *mm, unsigned long pfn)
1540 #ifdef CONFIG_FLATMEM
1541 BUG_ON(mem_map); /* should only be used early */
1543 make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
1544 pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
1547 /* Used for pmd and pud */
1548 static void __init xen_alloc_pmd_init(struct mm_struct *mm, unsigned long pfn)
1550 #ifdef CONFIG_FLATMEM
1551 BUG_ON(mem_map); /* should only be used early */
1553 make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
1556 /* Early release_pte assumes that all pts are pinned, since there's
1557 only init_mm and anything attached to that is pinned. */
1558 static void __init xen_release_pte_init(unsigned long pfn)
1560 pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
1561 make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
1564 static void __init xen_release_pmd_init(unsigned long pfn)
1566 make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
1569 static inline void __pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
1571 struct multicall_space mcs;
1572 struct mmuext_op *op;
1574 mcs = __xen_mc_entry(sizeof(*op));
1577 op->arg1.mfn = pfn_to_mfn(pfn);
1579 MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
1582 static inline void __set_pfn_prot(unsigned long pfn, pgprot_t prot)
1584 struct multicall_space mcs;
1585 unsigned long addr = (unsigned long)__va(pfn << PAGE_SHIFT);
1587 mcs = __xen_mc_entry(0);
1588 MULTI_update_va_mapping(mcs.mc, (unsigned long)addr,
1589 pfn_pte(pfn, prot), 0);
1592 /* This needs to make sure the new pte page is pinned iff its being
1593 attached to a pinned pagetable. */
1594 static inline void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn,
1597 bool pinned = PagePinned(virt_to_page(mm->pgd));
1599 trace_xen_mmu_alloc_ptpage(mm, pfn, level, pinned);
1602 struct page *page = pfn_to_page(pfn);
1604 SetPagePinned(page);
1606 if (!PageHighMem(page)) {
1609 __set_pfn_prot(pfn, PAGE_KERNEL_RO);
1611 if (level == PT_PTE && USE_SPLIT_PTLOCKS)
1612 __pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
1614 xen_mc_issue(PARAVIRT_LAZY_MMU);
1616 /* make sure there are no stray mappings of
1618 kmap_flush_unused();
1623 static void xen_alloc_pte(struct mm_struct *mm, unsigned long pfn)
1625 xen_alloc_ptpage(mm, pfn, PT_PTE);
1628 static void xen_alloc_pmd(struct mm_struct *mm, unsigned long pfn)
1630 xen_alloc_ptpage(mm, pfn, PT_PMD);
1633 /* This should never happen until we're OK to use struct page */
1634 static inline void xen_release_ptpage(unsigned long pfn, unsigned level)
1636 struct page *page = pfn_to_page(pfn);
1637 bool pinned = PagePinned(page);
1639 trace_xen_mmu_release_ptpage(pfn, level, pinned);
1642 if (!PageHighMem(page)) {
1645 if (level == PT_PTE && USE_SPLIT_PTLOCKS)
1646 __pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
1648 __set_pfn_prot(pfn, PAGE_KERNEL);
1650 xen_mc_issue(PARAVIRT_LAZY_MMU);
1652 ClearPagePinned(page);
1656 static void xen_release_pte(unsigned long pfn)
1658 xen_release_ptpage(pfn, PT_PTE);
1661 static void xen_release_pmd(unsigned long pfn)
1663 xen_release_ptpage(pfn, PT_PMD);
1666 #if PAGETABLE_LEVELS == 4
1667 static void xen_alloc_pud(struct mm_struct *mm, unsigned long pfn)
1669 xen_alloc_ptpage(mm, pfn, PT_PUD);
1672 static void xen_release_pud(unsigned long pfn)
1674 xen_release_ptpage(pfn, PT_PUD);
1678 void __init xen_reserve_top(void)
1680 #ifdef CONFIG_X86_32
1681 unsigned long top = HYPERVISOR_VIRT_START;
1682 struct xen_platform_parameters pp;
1684 if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0)
1685 top = pp.virt_start;
1687 reserve_top_address(-top);
1688 #endif /* CONFIG_X86_32 */
1692 * Like __va(), but returns address in the kernel mapping (which is
1693 * all we have until the physical memory mapping has been set up.
1695 static void *__ka(phys_addr_t paddr)
1697 #ifdef CONFIG_X86_64
1698 return (void *)(paddr + __START_KERNEL_map);
1704 /* Convert a machine address to physical address */
1705 static unsigned long m2p(phys_addr_t maddr)
1709 maddr &= PTE_PFN_MASK;
1710 paddr = mfn_to_pfn(maddr >> PAGE_SHIFT) << PAGE_SHIFT;
1715 /* Convert a machine address to kernel virtual */
1716 static void *m2v(phys_addr_t maddr)
1718 return __ka(m2p(maddr));
1721 /* Set the page permissions on an identity-mapped pages */
1722 static void set_page_prot(void *addr, pgprot_t prot)
1724 unsigned long pfn = __pa(addr) >> PAGE_SHIFT;
1725 pte_t pte = pfn_pte(pfn, prot);
1727 if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, 0))
1730 #ifdef CONFIG_X86_32
1731 static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
1733 unsigned pmdidx, pteidx;
1737 level1_ident_pgt = extend_brk(sizeof(pte_t) * LEVEL1_IDENT_ENTRIES,
1742 for (pmdidx = 0; pmdidx < PTRS_PER_PMD && pfn < max_pfn; pmdidx++) {
1745 /* Reuse or allocate a page of ptes */
1746 if (pmd_present(pmd[pmdidx]))
1747 pte_page = m2v(pmd[pmdidx].pmd);
1749 /* Check for free pte pages */
1750 if (ident_pte == LEVEL1_IDENT_ENTRIES)
1753 pte_page = &level1_ident_pgt[ident_pte];
1754 ident_pte += PTRS_PER_PTE;
1756 pmd[pmdidx] = __pmd(__pa(pte_page) | _PAGE_TABLE);
1759 /* Install mappings */
1760 for (pteidx = 0; pteidx < PTRS_PER_PTE; pteidx++, pfn++) {
1763 #ifdef CONFIG_X86_32
1764 if (pfn > max_pfn_mapped)
1765 max_pfn_mapped = pfn;
1768 if (!pte_none(pte_page[pteidx]))
1771 pte = pfn_pte(pfn, PAGE_KERNEL_EXEC);
1772 pte_page[pteidx] = pte;
1776 for (pteidx = 0; pteidx < ident_pte; pteidx += PTRS_PER_PTE)
1777 set_page_prot(&level1_ident_pgt[pteidx], PAGE_KERNEL_RO);
1779 set_page_prot(pmd, PAGE_KERNEL_RO);
1782 void __init xen_setup_machphys_mapping(void)
1784 struct xen_machphys_mapping mapping;
1786 if (HYPERVISOR_memory_op(XENMEM_machphys_mapping, &mapping) == 0) {
1787 machine_to_phys_mapping = (unsigned long *)mapping.v_start;
1788 machine_to_phys_nr = mapping.max_mfn + 1;
1790 machine_to_phys_nr = MACH2PHYS_NR_ENTRIES;
1792 #ifdef CONFIG_X86_32
1793 WARN_ON((machine_to_phys_mapping + (machine_to_phys_nr - 1))
1794 < machine_to_phys_mapping);
1798 #ifdef CONFIG_X86_64
1799 static void convert_pfn_mfn(void *v)
1804 /* All levels are converted the same way, so just treat them
1806 for (i = 0; i < PTRS_PER_PTE; i++)
1807 pte[i] = xen_make_pte(pte[i].pte);
1809 static void __init check_pt_base(unsigned long *pt_base, unsigned long *pt_end,
1812 if (*pt_base == PFN_DOWN(__pa(addr))) {
1813 set_page_prot((void *)addr, PAGE_KERNEL);
1814 clear_page((void *)addr);
1817 if (*pt_end == PFN_DOWN(__pa(addr))) {
1818 set_page_prot((void *)addr, PAGE_KERNEL);
1819 clear_page((void *)addr);
1824 * Set up the initial kernel pagetable.
1826 * We can construct this by grafting the Xen provided pagetable into
1827 * head_64.S's preconstructed pagetables. We copy the Xen L2's into
1828 * level2_ident_pgt, level2_kernel_pgt and level2_fixmap_pgt. This
1829 * means that only the kernel has a physical mapping to start with -
1830 * but that's enough to get __va working. We need to fill in the rest
1831 * of the physical mapping once some sort of allocator has been set
1834 void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
1838 unsigned long addr[3];
1839 unsigned long pt_base, pt_end;
1842 /* max_pfn_mapped is the last pfn mapped in the initial memory
1843 * mappings. Considering that on Xen after the kernel mappings we
1844 * have the mappings of some pages that don't exist in pfn space, we
1845 * set max_pfn_mapped to the last real pfn mapped. */
1846 max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));
1848 pt_base = PFN_DOWN(__pa(xen_start_info->pt_base));
1849 pt_end = pt_base + xen_start_info->nr_pt_frames;
1851 /* Zap identity mapping */
1852 init_level4_pgt[0] = __pgd(0);
1854 /* Pre-constructed entries are in pfn, so convert to mfn */
1855 /* L4[272] -> level3_ident_pgt
1856 * L4[511] -> level3_kernel_pgt */
1857 convert_pfn_mfn(init_level4_pgt);
1859 /* L3_i[0] -> level2_ident_pgt */
1860 convert_pfn_mfn(level3_ident_pgt);
1861 /* L3_k[510] -> level2_kernel_pgt
1862 * L3_i[511] -> level2_fixmap_pgt */
1863 convert_pfn_mfn(level3_kernel_pgt);
1865 /* We get [511][511] and have Xen's version of level2_kernel_pgt */
1866 l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd);
1867 l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud);
1869 addr[0] = (unsigned long)pgd;
1870 addr[1] = (unsigned long)l3;
1871 addr[2] = (unsigned long)l2;
1872 /* Graft it onto L4[272][0]. Note that we creating an aliasing problem:
1873 * Both L4[272][0] and L4[511][511] have entries that point to the same
1874 * L2 (PMD) tables. Meaning that if you modify it in __va space
1875 * it will be also modified in the __ka space! (But if you just
1876 * modify the PMD table to point to other PTE's or none, then you
1877 * are OK - which is what cleanup_highmap does) */
1878 copy_page(level2_ident_pgt, l2);
1879 /* Graft it onto L4[511][511] */
1880 copy_page(level2_kernel_pgt, l2);
1882 /* Get [511][510] and graft that in level2_fixmap_pgt */
1883 l3 = m2v(pgd[pgd_index(__START_KERNEL_map + PMD_SIZE)].pgd);
1884 l2 = m2v(l3[pud_index(__START_KERNEL_map + PMD_SIZE)].pud);
1885 copy_page(level2_fixmap_pgt, l2);
1886 /* Note that we don't do anything with level1_fixmap_pgt which
1889 /* Make pagetable pieces RO */
1890 set_page_prot(init_level4_pgt, PAGE_KERNEL_RO);
1891 set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO);
1892 set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO);
1893 set_page_prot(level3_user_vsyscall, PAGE_KERNEL_RO);
1894 set_page_prot(level2_ident_pgt, PAGE_KERNEL_RO);
1895 set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
1896 set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO);
1898 /* Pin down new L4 */
1899 pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE,
1900 PFN_DOWN(__pa_symbol(init_level4_pgt)));
1902 /* Unpin Xen-provided one */
1903 pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
1906 * At this stage there can be no user pgd, and no page
1907 * structure to attach it to, so make sure we just set kernel
1911 __xen_write_cr3(true, __pa(init_level4_pgt));
1912 xen_mc_issue(PARAVIRT_LAZY_CPU);
1914 /* We can't that easily rip out L3 and L2, as the Xen pagetables are
1915 * set out this way: [L4], [L1], [L2], [L3], [L1], [L1] ... for
1916 * the initial domain. For guests using the toolstack, they are in:
1917 * [L4], [L3], [L2], [L1], [L1], order .. So for dom0 we can only
1918 * rip out the [L4] (pgd), but for guests we shave off three pages.
1920 for (i = 0; i < ARRAY_SIZE(addr); i++)
1921 check_pt_base(&pt_base, &pt_end, addr[i]);
1923 /* Our (by three pages) smaller Xen pagetable that we are using */
1924 memblock_reserve(PFN_PHYS(pt_base), (pt_end - pt_base) * PAGE_SIZE);
1925 /* Revector the xen_start_info */
1926 xen_start_info = (struct start_info *)__va(__pa(xen_start_info));
1928 #else /* !CONFIG_X86_64 */
1929 static RESERVE_BRK_ARRAY(pmd_t, initial_kernel_pmd, PTRS_PER_PMD);
1930 static RESERVE_BRK_ARRAY(pmd_t, swapper_kernel_pmd, PTRS_PER_PMD);
1932 static void __init xen_write_cr3_init(unsigned long cr3)
1934 unsigned long pfn = PFN_DOWN(__pa(swapper_pg_dir));
1936 BUG_ON(read_cr3() != __pa(initial_page_table));
1937 BUG_ON(cr3 != __pa(swapper_pg_dir));
1940 * We are switching to swapper_pg_dir for the first time (from
1941 * initial_page_table) and therefore need to mark that page
1942 * read-only and then pin it.
1944 * Xen disallows sharing of kernel PMDs for PAE
1945 * guests. Therefore we must copy the kernel PMD from
1946 * initial_page_table into a new kernel PMD to be used in
1949 swapper_kernel_pmd =
1950 extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
1951 copy_page(swapper_kernel_pmd, initial_kernel_pmd);
1952 swapper_pg_dir[KERNEL_PGD_BOUNDARY] =
1953 __pgd(__pa(swapper_kernel_pmd) | _PAGE_PRESENT);
1954 set_page_prot(swapper_kernel_pmd, PAGE_KERNEL_RO);
1956 set_page_prot(swapper_pg_dir, PAGE_KERNEL_RO);
1958 pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, pfn);
1960 pin_pagetable_pfn(MMUEXT_UNPIN_TABLE,
1961 PFN_DOWN(__pa(initial_page_table)));
1962 set_page_prot(initial_page_table, PAGE_KERNEL);
1963 set_page_prot(initial_kernel_pmd, PAGE_KERNEL);
1965 pv_mmu_ops.write_cr3 = &xen_write_cr3;
1968 void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
1972 initial_kernel_pmd =
1973 extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
1975 max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->pt_base) +
1976 xen_start_info->nr_pt_frames * PAGE_SIZE +
1979 kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
1980 copy_page(initial_kernel_pmd, kernel_pmd);
1982 xen_map_identity_early(initial_kernel_pmd, max_pfn);
1984 copy_page(initial_page_table, pgd);
1985 initial_page_table[KERNEL_PGD_BOUNDARY] =
1986 __pgd(__pa(initial_kernel_pmd) | _PAGE_PRESENT);
1988 set_page_prot(initial_kernel_pmd, PAGE_KERNEL_RO);
1989 set_page_prot(initial_page_table, PAGE_KERNEL_RO);
1990 set_page_prot(empty_zero_page, PAGE_KERNEL_RO);
1992 pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
1994 pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE,
1995 PFN_DOWN(__pa(initial_page_table)));
1996 xen_write_cr3(__pa(initial_page_table));
1998 memblock_reserve(__pa(xen_start_info->pt_base),
1999 xen_start_info->nr_pt_frames * PAGE_SIZE);
2001 #endif /* CONFIG_X86_64 */
2003 static unsigned char dummy_mapping[PAGE_SIZE] __page_aligned_bss;
2005 static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
2009 phys >>= PAGE_SHIFT;
2012 case FIX_BTMAP_END ... FIX_BTMAP_BEGIN:
2013 #ifdef CONFIG_X86_F00F_BUG
2016 #ifdef CONFIG_X86_32
2019 # ifdef CONFIG_HIGHMEM
2020 case FIX_KMAP_BEGIN ... FIX_KMAP_END:
2023 case VSYSCALL_LAST_PAGE ... VSYSCALL_FIRST_PAGE:
2026 case FIX_TEXT_POKE0:
2027 case FIX_TEXT_POKE1:
2028 /* All local page mappings */
2029 pte = pfn_pte(phys, prot);
2032 #ifdef CONFIG_X86_LOCAL_APIC
2033 case FIX_APIC_BASE: /* maps dummy local APIC */
2034 pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
2038 #ifdef CONFIG_X86_IO_APIC
2039 case FIX_IO_APIC_BASE_0 ... FIX_IO_APIC_BASE_END:
2041 * We just don't map the IO APIC - all access is via
2042 * hypercalls. Keep the address in the pte for reference.
2044 pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
2048 case FIX_PARAVIRT_BOOTMAP:
2049 /* This is an MFN, but it isn't an IO mapping from the
2051 pte = mfn_pte(phys, prot);
2055 /* By default, set_fixmap is used for hardware mappings */
2056 pte = mfn_pte(phys, __pgprot(pgprot_val(prot) | _PAGE_IOMAP));
2060 __native_set_fixmap(idx, pte);
2062 #ifdef CONFIG_X86_64
2063 /* Replicate changes to map the vsyscall page into the user
2064 pagetable vsyscall mapping. */
2065 if ((idx >= VSYSCALL_LAST_PAGE && idx <= VSYSCALL_FIRST_PAGE) ||
2067 unsigned long vaddr = __fix_to_virt(idx);
2068 set_pte_vaddr_pud(level3_user_vsyscall, vaddr, pte);
2073 static void __init xen_post_allocator_init(void)
2075 pv_mmu_ops.set_pte = xen_set_pte;
2076 pv_mmu_ops.set_pmd = xen_set_pmd;
2077 pv_mmu_ops.set_pud = xen_set_pud;
2078 #if PAGETABLE_LEVELS == 4
2079 pv_mmu_ops.set_pgd = xen_set_pgd;
2082 /* This will work as long as patching hasn't happened yet
2083 (which it hasn't) */
2084 pv_mmu_ops.alloc_pte = xen_alloc_pte;
2085 pv_mmu_ops.alloc_pmd = xen_alloc_pmd;
2086 pv_mmu_ops.release_pte = xen_release_pte;
2087 pv_mmu_ops.release_pmd = xen_release_pmd;
2088 #if PAGETABLE_LEVELS == 4
2089 pv_mmu_ops.alloc_pud = xen_alloc_pud;
2090 pv_mmu_ops.release_pud = xen_release_pud;
2093 #ifdef CONFIG_X86_64
2094 SetPagePinned(virt_to_page(level3_user_vsyscall));
2096 xen_mark_init_mm_pinned();
2099 static void xen_leave_lazy_mmu(void)
2103 paravirt_leave_lazy_mmu();
2107 static const struct pv_mmu_ops xen_mmu_ops __initconst = {
2108 .read_cr2 = xen_read_cr2,
2109 .write_cr2 = xen_write_cr2,
2111 .read_cr3 = xen_read_cr3,
2112 #ifdef CONFIG_X86_32
2113 .write_cr3 = xen_write_cr3_init,
2115 .write_cr3 = xen_write_cr3,
2118 .flush_tlb_user = xen_flush_tlb,
2119 .flush_tlb_kernel = xen_flush_tlb,
2120 .flush_tlb_single = xen_flush_tlb_single,
2121 .flush_tlb_others = xen_flush_tlb_others,
2123 .pte_update = paravirt_nop,
2124 .pte_update_defer = paravirt_nop,
2126 .pgd_alloc = xen_pgd_alloc,
2127 .pgd_free = xen_pgd_free,
2129 .alloc_pte = xen_alloc_pte_init,
2130 .release_pte = xen_release_pte_init,
2131 .alloc_pmd = xen_alloc_pmd_init,
2132 .release_pmd = xen_release_pmd_init,
2134 .set_pte = xen_set_pte_init,
2135 .set_pte_at = xen_set_pte_at,
2136 .set_pmd = xen_set_pmd_hyper,
2138 .ptep_modify_prot_start = __ptep_modify_prot_start,
2139 .ptep_modify_prot_commit = __ptep_modify_prot_commit,
2141 .pte_val = PV_CALLEE_SAVE(xen_pte_val),
2142 .pgd_val = PV_CALLEE_SAVE(xen_pgd_val),
2144 .make_pte = PV_CALLEE_SAVE(xen_make_pte),
2145 .make_pgd = PV_CALLEE_SAVE(xen_make_pgd),
2147 #ifdef CONFIG_X86_PAE
2148 .set_pte_atomic = xen_set_pte_atomic,
2149 .pte_clear = xen_pte_clear,
2150 .pmd_clear = xen_pmd_clear,
2151 #endif /* CONFIG_X86_PAE */
2152 .set_pud = xen_set_pud_hyper,
2154 .make_pmd = PV_CALLEE_SAVE(xen_make_pmd),
2155 .pmd_val = PV_CALLEE_SAVE(xen_pmd_val),
2157 #if PAGETABLE_LEVELS == 4
2158 .pud_val = PV_CALLEE_SAVE(xen_pud_val),
2159 .make_pud = PV_CALLEE_SAVE(xen_make_pud),
2160 .set_pgd = xen_set_pgd_hyper,
2162 .alloc_pud = xen_alloc_pmd_init,
2163 .release_pud = xen_release_pmd_init,
2164 #endif /* PAGETABLE_LEVELS == 4 */
2166 .activate_mm = xen_activate_mm,
2167 .dup_mmap = xen_dup_mmap,
2168 .exit_mmap = xen_exit_mmap,
2171 .enter = paravirt_enter_lazy_mmu,
2172 .leave = xen_leave_lazy_mmu,
2175 .set_fixmap = xen_set_fixmap,
2178 void __init xen_init_mmu_ops(void)
2180 x86_init.mapping.pagetable_reserve = xen_mapping_pagetable_reserve;
2181 x86_init.paging.pagetable_init = xen_pagetable_init;
2182 pv_mmu_ops = xen_mmu_ops;
2184 memset(dummy_mapping, 0xff, PAGE_SIZE);
2187 /* Protected by xen_reservation_lock. */
2188 #define MAX_CONTIG_ORDER 9 /* 2MB */
2189 static unsigned long discontig_frames[1<<MAX_CONTIG_ORDER];
2191 #define VOID_PTE (mfn_pte(0, __pgprot(0)))
2192 static void xen_zap_pfn_range(unsigned long vaddr, unsigned int order,
2193 unsigned long *in_frames,
2194 unsigned long *out_frames)
2197 struct multicall_space mcs;
2200 for (i = 0; i < (1UL<<order); i++, vaddr += PAGE_SIZE) {
2201 mcs = __xen_mc_entry(0);
2204 in_frames[i] = virt_to_mfn(vaddr);
2206 MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0);
2207 __set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);
2210 out_frames[i] = virt_to_pfn(vaddr);
2216 * Update the pfn-to-mfn mappings for a virtual address range, either to
2217 * point to an array of mfns, or contiguously from a single starting
2220 static void xen_remap_exchanged_ptes(unsigned long vaddr, int order,
2221 unsigned long *mfns,
2222 unsigned long first_mfn)
2229 limit = 1u << order;
2230 for (i = 0; i < limit; i++, vaddr += PAGE_SIZE) {
2231 struct multicall_space mcs;
2234 mcs = __xen_mc_entry(0);
2238 mfn = first_mfn + i;
2240 if (i < (limit - 1))
2244 flags = UVMF_INVLPG | UVMF_ALL;
2246 flags = UVMF_TLB_FLUSH | UVMF_ALL;
2249 MULTI_update_va_mapping(mcs.mc, vaddr,
2250 mfn_pte(mfn, PAGE_KERNEL), flags);
2252 set_phys_to_machine(virt_to_pfn(vaddr), mfn);
2259 * Perform the hypercall to exchange a region of our pfns to point to
2260 * memory with the required contiguous alignment. Takes the pfns as
2261 * input, and populates mfns as output.
2263 * Returns a success code indicating whether the hypervisor was able to
2264 * satisfy the request or not.
2266 static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in,
2267 unsigned long *pfns_in,
2268 unsigned long extents_out,
2269 unsigned int order_out,
2270 unsigned long *mfns_out,
2271 unsigned int address_bits)
2276 struct xen_memory_exchange exchange = {
2278 .nr_extents = extents_in,
2279 .extent_order = order_in,
2280 .extent_start = pfns_in,
2284 .nr_extents = extents_out,
2285 .extent_order = order_out,
2286 .extent_start = mfns_out,
2287 .address_bits = address_bits,
2292 BUG_ON(extents_in << order_in != extents_out << order_out);
2294 rc = HYPERVISOR_memory_op(XENMEM_exchange, &exchange);
2295 success = (exchange.nr_exchanged == extents_in);
2297 BUG_ON(!success && ((exchange.nr_exchanged != 0) || (rc == 0)));
2298 BUG_ON(success && (rc != 0));
2303 int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
2304 unsigned int address_bits)
2306 unsigned long *in_frames = discontig_frames, out_frame;
2307 unsigned long flags;
2311 * Currently an auto-translated guest will not perform I/O, nor will
2312 * it require PAE page directories below 4GB. Therefore any calls to
2313 * this function are redundant and can be ignored.
2316 if (xen_feature(XENFEAT_auto_translated_physmap))
2319 if (unlikely(order > MAX_CONTIG_ORDER))
2322 memset((void *) vstart, 0, PAGE_SIZE << order);
2324 spin_lock_irqsave(&xen_reservation_lock, flags);
2326 /* 1. Zap current PTEs, remembering MFNs. */
2327 xen_zap_pfn_range(vstart, order, in_frames, NULL);
2329 /* 2. Get a new contiguous memory extent. */
2330 out_frame = virt_to_pfn(vstart);
2331 success = xen_exchange_memory(1UL << order, 0, in_frames,
2332 1, order, &out_frame,
2335 /* 3. Map the new extent in place of old pages. */
2337 xen_remap_exchanged_ptes(vstart, order, NULL, out_frame);
2339 xen_remap_exchanged_ptes(vstart, order, in_frames, 0);
2341 spin_unlock_irqrestore(&xen_reservation_lock, flags);
2343 return success ? 0 : -ENOMEM;
2345 EXPORT_SYMBOL_GPL(xen_create_contiguous_region);
2347 void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order)
2349 unsigned long *out_frames = discontig_frames, in_frame;
2350 unsigned long flags;
2353 if (xen_feature(XENFEAT_auto_translated_physmap))
2356 if (unlikely(order > MAX_CONTIG_ORDER))
2359 memset((void *) vstart, 0, PAGE_SIZE << order);
2361 spin_lock_irqsave(&xen_reservation_lock, flags);
2363 /* 1. Find start MFN of contiguous extent. */
2364 in_frame = virt_to_mfn(vstart);
2366 /* 2. Zap current PTEs. */
2367 xen_zap_pfn_range(vstart, order, NULL, out_frames);
2369 /* 3. Do the exchange for non-contiguous MFNs. */
2370 success = xen_exchange_memory(1, order, &in_frame, 1UL << order,
2373 /* 4. Map new pages in place of old pages. */
2375 xen_remap_exchanged_ptes(vstart, order, out_frames, 0);
2377 xen_remap_exchanged_ptes(vstart, order, NULL, in_frame);
2379 spin_unlock_irqrestore(&xen_reservation_lock, flags);
2381 EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
2383 #ifdef CONFIG_XEN_PVHVM
2384 static void xen_hvm_exit_mmap(struct mm_struct *mm)
2386 struct xen_hvm_pagetable_dying a;
2389 a.domid = DOMID_SELF;
2390 a.gpa = __pa(mm->pgd);
2391 rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a);
2392 WARN_ON_ONCE(rc < 0);
2395 static int is_pagetable_dying_supported(void)
2397 struct xen_hvm_pagetable_dying a;
2400 a.domid = DOMID_SELF;
2402 rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a);
2404 printk(KERN_DEBUG "HVMOP_pagetable_dying not supported\n");
2410 void __init xen_hvm_init_mmu_ops(void)
2412 if (is_pagetable_dying_supported())
2413 pv_mmu_ops.exit_mmap = xen_hvm_exit_mmap;
2417 #define REMAP_BATCH_SIZE 16
2422 struct mmu_update *mmu_update;
2425 static int remap_area_mfn_pte_fn(pte_t *ptep, pgtable_t token,
2426 unsigned long addr, void *data)
2428 struct remap_data *rmd = data;
2429 pte_t pte = pte_mkspecial(pfn_pte(rmd->mfn++, rmd->prot));
2431 rmd->mmu_update->ptr = virt_to_machine(ptep).maddr;
2432 rmd->mmu_update->val = pte_val_ma(pte);
2438 int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
2440 unsigned long mfn, int nr,
2441 pgprot_t prot, unsigned domid)
2443 struct remap_data rmd;
2444 struct mmu_update mmu_update[REMAP_BATCH_SIZE];
2446 unsigned long range;
2449 if (xen_feature(XENFEAT_auto_translated_physmap))
2452 prot = __pgprot(pgprot_val(prot) | _PAGE_IOMAP);
2454 BUG_ON(!((vma->vm_flags & (VM_PFNMAP | VM_RESERVED | VM_IO)) ==
2455 (VM_PFNMAP | VM_RESERVED | VM_IO)));
2461 batch = min(REMAP_BATCH_SIZE, nr);
2462 range = (unsigned long)batch << PAGE_SHIFT;
2464 rmd.mmu_update = mmu_update;
2465 err = apply_to_page_range(vma->vm_mm, addr, range,
2466 remap_area_mfn_pte_fn, &rmd);
2470 err = HYPERVISOR_mmu_update(mmu_update, batch, NULL, domid);
2485 EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_range);