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>
50 #include <linux/crash_dump.h>
52 #include <trace/events/xen.h>
54 #include <asm/pgtable.h>
55 #include <asm/tlbflush.h>
56 #include <asm/fixmap.h>
57 #include <asm/mmu_context.h>
58 #include <asm/setup.h>
59 #include <asm/paravirt.h>
61 #include <asm/linkage.h>
67 #include <asm/xen/hypercall.h>
68 #include <asm/xen/hypervisor.h>
72 #include <xen/interface/xen.h>
73 #include <xen/interface/hvm/hvm_op.h>
74 #include <xen/interface/version.h>
75 #include <xen/interface/memory.h>
76 #include <xen/hvc-console.h>
78 #include "multicalls.h"
83 * Protects atomic reservation decrease/increase against concurrent increases.
84 * Also protects non-atomic updates of current_pages and balloon lists.
86 DEFINE_SPINLOCK(xen_reservation_lock);
90 * Identity map, in addition to plain kernel map. This needs to be
91 * large enough to allocate page table pages to allocate the rest.
92 * Each page can map 2MB.
94 #define LEVEL1_IDENT_ENTRIES (PTRS_PER_PTE * 4)
95 static RESERVE_BRK_ARRAY(pte_t, level1_ident_pgt, LEVEL1_IDENT_ENTRIES);
98 /* l3 pud for userspace vsyscall mapping */
99 static pud_t level3_user_vsyscall[PTRS_PER_PUD] __page_aligned_bss;
100 #endif /* CONFIG_X86_64 */
103 * Note about cr3 (pagetable base) values:
105 * xen_cr3 contains the current logical cr3 value; it contains the
106 * last set cr3. This may not be the current effective cr3, because
107 * its update may be being lazily deferred. However, a vcpu looking
108 * at its own cr3 can use this value knowing that it everything will
109 * be self-consistent.
111 * xen_current_cr3 contains the actual vcpu cr3; it is set once the
112 * hypercall to set the vcpu cr3 is complete (so it may be a little
113 * out of date, but it will never be set early). If one vcpu is
114 * looking at another vcpu's cr3 value, it should use this variable.
116 DEFINE_PER_CPU(unsigned long, xen_cr3); /* cr3 stored as physaddr */
117 DEFINE_PER_CPU(unsigned long, xen_current_cr3); /* actual vcpu cr3 */
119 static phys_addr_t xen_pt_base, xen_pt_size __initdata;
122 * Just beyond the highest usermode address. STACK_TOP_MAX has a
123 * redzone above it, so round it up to a PGD boundary.
125 #define USER_LIMIT ((STACK_TOP_MAX + PGDIR_SIZE - 1) & PGDIR_MASK)
127 unsigned long arbitrary_virt_to_mfn(void *vaddr)
129 xmaddr_t maddr = arbitrary_virt_to_machine(vaddr);
131 return PFN_DOWN(maddr.maddr);
134 xmaddr_t arbitrary_virt_to_machine(void *vaddr)
136 unsigned long address = (unsigned long)vaddr;
142 * if the PFN is in the linear mapped vaddr range, we can just use
143 * the (quick) virt_to_machine() p2m lookup
145 if (virt_addr_valid(vaddr))
146 return virt_to_machine(vaddr);
148 /* otherwise we have to do a (slower) full page-table walk */
150 pte = lookup_address(address, &level);
152 offset = address & ~PAGE_MASK;
153 return XMADDR(((phys_addr_t)pte_mfn(*pte) << PAGE_SHIFT) + offset);
155 EXPORT_SYMBOL_GPL(arbitrary_virt_to_machine);
157 void make_lowmem_page_readonly(void *vaddr)
160 unsigned long address = (unsigned long)vaddr;
163 pte = lookup_address(address, &level);
165 return; /* vaddr missing */
167 ptev = pte_wrprotect(*pte);
169 if (HYPERVISOR_update_va_mapping(address, ptev, 0))
173 void make_lowmem_page_readwrite(void *vaddr)
176 unsigned long address = (unsigned long)vaddr;
179 pte = lookup_address(address, &level);
181 return; /* vaddr missing */
183 ptev = pte_mkwrite(*pte);
185 if (HYPERVISOR_update_va_mapping(address, ptev, 0))
190 static bool xen_page_pinned(void *ptr)
192 struct page *page = virt_to_page(ptr);
194 return PagePinned(page);
197 void xen_set_domain_pte(pte_t *ptep, pte_t pteval, unsigned domid)
199 struct multicall_space mcs;
200 struct mmu_update *u;
202 trace_xen_mmu_set_domain_pte(ptep, pteval, domid);
204 mcs = xen_mc_entry(sizeof(*u));
207 /* ptep might be kmapped when using 32-bit HIGHPTE */
208 u->ptr = virt_to_machine(ptep).maddr;
209 u->val = pte_val_ma(pteval);
211 MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, domid);
213 xen_mc_issue(PARAVIRT_LAZY_MMU);
215 EXPORT_SYMBOL_GPL(xen_set_domain_pte);
217 static void xen_extend_mmu_update(const struct mmu_update *update)
219 struct multicall_space mcs;
220 struct mmu_update *u;
222 mcs = xen_mc_extend_args(__HYPERVISOR_mmu_update, sizeof(*u));
224 if (mcs.mc != NULL) {
227 mcs = __xen_mc_entry(sizeof(*u));
228 MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
235 static void xen_extend_mmuext_op(const struct mmuext_op *op)
237 struct multicall_space mcs;
240 mcs = xen_mc_extend_args(__HYPERVISOR_mmuext_op, sizeof(*u));
242 if (mcs.mc != NULL) {
245 mcs = __xen_mc_entry(sizeof(*u));
246 MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
253 static void xen_set_pmd_hyper(pmd_t *ptr, pmd_t val)
261 /* ptr may be ioremapped for 64-bit pagetable setup */
262 u.ptr = arbitrary_virt_to_machine(ptr).maddr;
263 u.val = pmd_val_ma(val);
264 xen_extend_mmu_update(&u);
266 xen_mc_issue(PARAVIRT_LAZY_MMU);
271 static void xen_set_pmd(pmd_t *ptr, pmd_t val)
273 trace_xen_mmu_set_pmd(ptr, val);
275 /* If page is not pinned, we can just update the entry
277 if (!xen_page_pinned(ptr)) {
282 xen_set_pmd_hyper(ptr, val);
286 * Associate a virtual page frame with a given physical page frame
287 * and protection flags for that frame.
289 void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags)
291 set_pte_vaddr(vaddr, mfn_pte(mfn, flags));
294 static bool xen_batched_set_pte(pte_t *ptep, pte_t pteval)
298 if (paravirt_get_lazy_mode() != PARAVIRT_LAZY_MMU)
303 u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE;
304 u.val = pte_val_ma(pteval);
305 xen_extend_mmu_update(&u);
307 xen_mc_issue(PARAVIRT_LAZY_MMU);
312 static inline void __xen_set_pte(pte_t *ptep, pte_t pteval)
314 if (!xen_batched_set_pte(ptep, pteval)) {
316 * Could call native_set_pte() here and trap and
317 * emulate the PTE write but with 32-bit guests this
318 * needs two traps (one for each of the two 32-bit
319 * words in the PTE) so do one hypercall directly
324 u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE;
325 u.val = pte_val_ma(pteval);
326 HYPERVISOR_mmu_update(&u, 1, NULL, DOMID_SELF);
330 static void xen_set_pte(pte_t *ptep, pte_t pteval)
332 trace_xen_mmu_set_pte(ptep, pteval);
333 __xen_set_pte(ptep, pteval);
336 static void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
337 pte_t *ptep, pte_t pteval)
339 trace_xen_mmu_set_pte_at(mm, addr, ptep, pteval);
340 __xen_set_pte(ptep, pteval);
343 pte_t xen_ptep_modify_prot_start(struct mm_struct *mm,
344 unsigned long addr, pte_t *ptep)
346 /* Just return the pte as-is. We preserve the bits on commit */
347 trace_xen_mmu_ptep_modify_prot_start(mm, addr, ptep, *ptep);
351 void xen_ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr,
352 pte_t *ptep, pte_t pte)
356 trace_xen_mmu_ptep_modify_prot_commit(mm, addr, ptep, pte);
359 u.ptr = virt_to_machine(ptep).maddr | MMU_PT_UPDATE_PRESERVE_AD;
360 u.val = pte_val_ma(pte);
361 xen_extend_mmu_update(&u);
363 xen_mc_issue(PARAVIRT_LAZY_MMU);
366 /* Assume pteval_t is equivalent to all the other *val_t types. */
367 static pteval_t pte_mfn_to_pfn(pteval_t val)
369 if (val & _PAGE_PRESENT) {
370 unsigned long mfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
371 unsigned long pfn = mfn_to_pfn(mfn);
373 pteval_t flags = val & PTE_FLAGS_MASK;
374 if (unlikely(pfn == ~0))
375 val = flags & ~_PAGE_PRESENT;
377 val = ((pteval_t)pfn << PAGE_SHIFT) | flags;
383 static pteval_t pte_pfn_to_mfn(pteval_t val)
385 if (val & _PAGE_PRESENT) {
386 unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
387 pteval_t flags = val & PTE_FLAGS_MASK;
390 if (!xen_feature(XENFEAT_auto_translated_physmap))
391 mfn = __pfn_to_mfn(pfn);
395 * If there's no mfn for the pfn, then just create an
396 * empty non-present pte. Unfortunately this loses
397 * information about the original pfn, so
398 * pte_mfn_to_pfn is asymmetric.
400 if (unlikely(mfn == INVALID_P2M_ENTRY)) {
404 mfn &= ~(FOREIGN_FRAME_BIT | IDENTITY_FRAME_BIT);
405 val = ((pteval_t)mfn << PAGE_SHIFT) | flags;
411 __visible pteval_t xen_pte_val(pte_t pte)
413 pteval_t pteval = pte.pte;
415 return pte_mfn_to_pfn(pteval);
417 PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val);
419 __visible pgdval_t xen_pgd_val(pgd_t pgd)
421 return pte_mfn_to_pfn(pgd.pgd);
423 PV_CALLEE_SAVE_REGS_THUNK(xen_pgd_val);
425 __visible pte_t xen_make_pte(pteval_t pte)
427 pte = pte_pfn_to_mfn(pte);
429 return native_make_pte(pte);
431 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte);
433 __visible pgd_t xen_make_pgd(pgdval_t pgd)
435 pgd = pte_pfn_to_mfn(pgd);
436 return native_make_pgd(pgd);
438 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pgd);
440 __visible pmdval_t xen_pmd_val(pmd_t pmd)
442 return pte_mfn_to_pfn(pmd.pmd);
444 PV_CALLEE_SAVE_REGS_THUNK(xen_pmd_val);
446 static void xen_set_pud_hyper(pud_t *ptr, pud_t val)
454 /* ptr may be ioremapped for 64-bit pagetable setup */
455 u.ptr = arbitrary_virt_to_machine(ptr).maddr;
456 u.val = pud_val_ma(val);
457 xen_extend_mmu_update(&u);
459 xen_mc_issue(PARAVIRT_LAZY_MMU);
464 static void xen_set_pud(pud_t *ptr, pud_t val)
466 trace_xen_mmu_set_pud(ptr, val);
468 /* If page is not pinned, we can just update the entry
470 if (!xen_page_pinned(ptr)) {
475 xen_set_pud_hyper(ptr, val);
478 #ifdef CONFIG_X86_PAE
479 static void xen_set_pte_atomic(pte_t *ptep, pte_t pte)
481 trace_xen_mmu_set_pte_atomic(ptep, pte);
482 set_64bit((u64 *)ptep, native_pte_val(pte));
485 static void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
487 trace_xen_mmu_pte_clear(mm, addr, ptep);
488 if (!xen_batched_set_pte(ptep, native_make_pte(0)))
489 native_pte_clear(mm, addr, ptep);
492 static void xen_pmd_clear(pmd_t *pmdp)
494 trace_xen_mmu_pmd_clear(pmdp);
495 set_pmd(pmdp, __pmd(0));
497 #endif /* CONFIG_X86_PAE */
499 __visible pmd_t xen_make_pmd(pmdval_t pmd)
501 pmd = pte_pfn_to_mfn(pmd);
502 return native_make_pmd(pmd);
504 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pmd);
506 #if CONFIG_PGTABLE_LEVELS == 4
507 __visible pudval_t xen_pud_val(pud_t pud)
509 return pte_mfn_to_pfn(pud.pud);
511 PV_CALLEE_SAVE_REGS_THUNK(xen_pud_val);
513 __visible pud_t xen_make_pud(pudval_t pud)
515 pud = pte_pfn_to_mfn(pud);
517 return native_make_pud(pud);
519 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pud);
521 static pgd_t *xen_get_user_pgd(pgd_t *pgd)
523 pgd_t *pgd_page = (pgd_t *)(((unsigned long)pgd) & PAGE_MASK);
524 unsigned offset = pgd - pgd_page;
525 pgd_t *user_ptr = NULL;
527 if (offset < pgd_index(USER_LIMIT)) {
528 struct page *page = virt_to_page(pgd_page);
529 user_ptr = (pgd_t *)page->private;
537 static void __xen_set_pgd_hyper(pgd_t *ptr, pgd_t val)
541 u.ptr = virt_to_machine(ptr).maddr;
542 u.val = pgd_val_ma(val);
543 xen_extend_mmu_update(&u);
547 * Raw hypercall-based set_pgd, intended for in early boot before
548 * there's a page structure. This implies:
549 * 1. The only existing pagetable is the kernel's
550 * 2. It is always pinned
551 * 3. It has no user pagetable attached to it
553 static void __init xen_set_pgd_hyper(pgd_t *ptr, pgd_t val)
559 __xen_set_pgd_hyper(ptr, val);
561 xen_mc_issue(PARAVIRT_LAZY_MMU);
566 static void xen_set_pgd(pgd_t *ptr, pgd_t val)
568 pgd_t *user_ptr = xen_get_user_pgd(ptr);
570 trace_xen_mmu_set_pgd(ptr, user_ptr, val);
572 /* If page is not pinned, we can just update the entry
574 if (!xen_page_pinned(ptr)) {
577 WARN_ON(xen_page_pinned(user_ptr));
583 /* If it's pinned, then we can at least batch the kernel and
584 user updates together. */
587 __xen_set_pgd_hyper(ptr, val);
589 __xen_set_pgd_hyper(user_ptr, val);
591 xen_mc_issue(PARAVIRT_LAZY_MMU);
593 #endif /* CONFIG_PGTABLE_LEVELS == 4 */
596 * (Yet another) pagetable walker. This one is intended for pinning a
597 * pagetable. This means that it walks a pagetable and calls the
598 * callback function on each page it finds making up the page table,
599 * at every level. It walks the entire pagetable, but it only bothers
600 * pinning pte pages which are below limit. In the normal case this
601 * will be STACK_TOP_MAX, but at boot we need to pin up to
604 * For 32-bit the important bit is that we don't pin beyond there,
605 * because then we start getting into Xen's ptes.
607 * For 64-bit, we must skip the Xen hole in the middle of the address
608 * space, just after the big x86-64 virtual hole.
610 static int __xen_pgd_walk(struct mm_struct *mm, pgd_t *pgd,
611 int (*func)(struct mm_struct *mm, struct page *,
616 unsigned hole_low, hole_high;
617 unsigned pgdidx_limit, pudidx_limit, pmdidx_limit;
618 unsigned pgdidx, pudidx, pmdidx;
620 /* The limit is the last byte to be touched */
622 BUG_ON(limit >= FIXADDR_TOP);
624 if (xen_feature(XENFEAT_auto_translated_physmap))
628 * 64-bit has a great big hole in the middle of the address
629 * space, which contains the Xen mappings. On 32-bit these
630 * will end up making a zero-sized hole and so is a no-op.
632 hole_low = pgd_index(USER_LIMIT);
633 hole_high = pgd_index(PAGE_OFFSET);
635 pgdidx_limit = pgd_index(limit);
637 pudidx_limit = pud_index(limit);
642 pmdidx_limit = pmd_index(limit);
647 for (pgdidx = 0; pgdidx <= pgdidx_limit; pgdidx++) {
650 if (pgdidx >= hole_low && pgdidx < hole_high)
653 if (!pgd_val(pgd[pgdidx]))
656 pud = pud_offset(&pgd[pgdidx], 0);
658 if (PTRS_PER_PUD > 1) /* not folded */
659 flush |= (*func)(mm, virt_to_page(pud), PT_PUD);
661 for (pudidx = 0; pudidx < PTRS_PER_PUD; pudidx++) {
664 if (pgdidx == pgdidx_limit &&
665 pudidx > pudidx_limit)
668 if (pud_none(pud[pudidx]))
671 pmd = pmd_offset(&pud[pudidx], 0);
673 if (PTRS_PER_PMD > 1) /* not folded */
674 flush |= (*func)(mm, virt_to_page(pmd), PT_PMD);
676 for (pmdidx = 0; pmdidx < PTRS_PER_PMD; pmdidx++) {
679 if (pgdidx == pgdidx_limit &&
680 pudidx == pudidx_limit &&
681 pmdidx > pmdidx_limit)
684 if (pmd_none(pmd[pmdidx]))
687 pte = pmd_page(pmd[pmdidx]);
688 flush |= (*func)(mm, pte, PT_PTE);
694 /* Do the top level last, so that the callbacks can use it as
695 a cue to do final things like tlb flushes. */
696 flush |= (*func)(mm, virt_to_page(pgd), PT_PGD);
701 static int xen_pgd_walk(struct mm_struct *mm,
702 int (*func)(struct mm_struct *mm, struct page *,
706 return __xen_pgd_walk(mm, mm->pgd, func, limit);
709 /* If we're using split pte locks, then take the page's lock and
710 return a pointer to it. Otherwise return NULL. */
711 static spinlock_t *xen_pte_lock(struct page *page, struct mm_struct *mm)
713 spinlock_t *ptl = NULL;
715 #if USE_SPLIT_PTE_PTLOCKS
716 ptl = ptlock_ptr(page);
717 spin_lock_nest_lock(ptl, &mm->page_table_lock);
723 static void xen_pte_unlock(void *v)
729 static void xen_do_pin(unsigned level, unsigned long pfn)
734 op.arg1.mfn = pfn_to_mfn(pfn);
736 xen_extend_mmuext_op(&op);
739 static int xen_pin_page(struct mm_struct *mm, struct page *page,
742 unsigned pgfl = TestSetPagePinned(page);
746 flush = 0; /* already pinned */
747 else if (PageHighMem(page))
748 /* kmaps need flushing if we found an unpinned
752 void *pt = lowmem_page_address(page);
753 unsigned long pfn = page_to_pfn(page);
754 struct multicall_space mcs = __xen_mc_entry(0);
760 * We need to hold the pagetable lock between the time
761 * we make the pagetable RO and when we actually pin
762 * it. If we don't, then other users may come in and
763 * attempt to update the pagetable by writing it,
764 * which will fail because the memory is RO but not
765 * pinned, so Xen won't do the trap'n'emulate.
767 * If we're using split pte locks, we can't hold the
768 * entire pagetable's worth of locks during the
769 * traverse, because we may wrap the preempt count (8
770 * bits). The solution is to mark RO and pin each PTE
771 * page while holding the lock. This means the number
772 * of locks we end up holding is never more than a
773 * batch size (~32 entries, at present).
775 * If we're not using split pte locks, we needn't pin
776 * the PTE pages independently, because we're
777 * protected by the overall pagetable lock.
781 ptl = xen_pte_lock(page, mm);
783 MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
784 pfn_pte(pfn, PAGE_KERNEL_RO),
785 level == PT_PGD ? UVMF_TLB_FLUSH : 0);
788 xen_do_pin(MMUEXT_PIN_L1_TABLE, pfn);
790 /* Queue a deferred unlock for when this batch
792 xen_mc_callback(xen_pte_unlock, ptl);
799 /* This is called just after a mm has been created, but it has not
800 been used yet. We need to make sure that its pagetable is all
801 read-only, and can be pinned. */
802 static void __xen_pgd_pin(struct mm_struct *mm, pgd_t *pgd)
804 trace_xen_mmu_pgd_pin(mm, pgd);
808 if (__xen_pgd_walk(mm, pgd, xen_pin_page, USER_LIMIT)) {
809 /* re-enable interrupts for flushing */
819 pgd_t *user_pgd = xen_get_user_pgd(pgd);
821 xen_do_pin(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(pgd)));
824 xen_pin_page(mm, virt_to_page(user_pgd), PT_PGD);
825 xen_do_pin(MMUEXT_PIN_L4_TABLE,
826 PFN_DOWN(__pa(user_pgd)));
829 #else /* CONFIG_X86_32 */
830 #ifdef CONFIG_X86_PAE
831 /* Need to make sure unshared kernel PMD is pinnable */
832 xen_pin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
835 xen_do_pin(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(pgd)));
836 #endif /* CONFIG_X86_64 */
840 static void xen_pgd_pin(struct mm_struct *mm)
842 __xen_pgd_pin(mm, mm->pgd);
846 * On save, we need to pin all pagetables to make sure they get their
847 * mfns turned into pfns. Search the list for any unpinned pgds and pin
848 * them (unpinned pgds are not currently in use, probably because the
849 * process is under construction or destruction).
851 * Expected to be called in stop_machine() ("equivalent to taking
852 * every spinlock in the system"), so the locking doesn't really
853 * matter all that much.
855 void xen_mm_pin_all(void)
859 spin_lock(&pgd_lock);
861 list_for_each_entry(page, &pgd_list, lru) {
862 if (!PagePinned(page)) {
863 __xen_pgd_pin(&init_mm, (pgd_t *)page_address(page));
864 SetPageSavePinned(page);
868 spin_unlock(&pgd_lock);
872 * The init_mm pagetable is really pinned as soon as its created, but
873 * that's before we have page structures to store the bits. So do all
874 * the book-keeping now.
876 static int __init xen_mark_pinned(struct mm_struct *mm, struct page *page,
883 static void __init xen_mark_init_mm_pinned(void)
885 xen_pgd_walk(&init_mm, xen_mark_pinned, FIXADDR_TOP);
888 static int xen_unpin_page(struct mm_struct *mm, struct page *page,
891 unsigned pgfl = TestClearPagePinned(page);
893 if (pgfl && !PageHighMem(page)) {
894 void *pt = lowmem_page_address(page);
895 unsigned long pfn = page_to_pfn(page);
896 spinlock_t *ptl = NULL;
897 struct multicall_space mcs;
900 * Do the converse to pin_page. If we're using split
901 * pte locks, we must be holding the lock for while
902 * the pte page is unpinned but still RO to prevent
903 * concurrent updates from seeing it in this
904 * partially-pinned state.
906 if (level == PT_PTE) {
907 ptl = xen_pte_lock(page, mm);
910 xen_do_pin(MMUEXT_UNPIN_TABLE, pfn);
913 mcs = __xen_mc_entry(0);
915 MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
916 pfn_pte(pfn, PAGE_KERNEL),
917 level == PT_PGD ? UVMF_TLB_FLUSH : 0);
920 /* unlock when batch completed */
921 xen_mc_callback(xen_pte_unlock, ptl);
925 return 0; /* never need to flush on unpin */
928 /* Release a pagetables pages back as normal RW */
929 static void __xen_pgd_unpin(struct mm_struct *mm, pgd_t *pgd)
931 trace_xen_mmu_pgd_unpin(mm, pgd);
935 xen_do_pin(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
939 pgd_t *user_pgd = xen_get_user_pgd(pgd);
942 xen_do_pin(MMUEXT_UNPIN_TABLE,
943 PFN_DOWN(__pa(user_pgd)));
944 xen_unpin_page(mm, virt_to_page(user_pgd), PT_PGD);
949 #ifdef CONFIG_X86_PAE
950 /* Need to make sure unshared kernel PMD is unpinned */
951 xen_unpin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
955 __xen_pgd_walk(mm, pgd, xen_unpin_page, USER_LIMIT);
960 static void xen_pgd_unpin(struct mm_struct *mm)
962 __xen_pgd_unpin(mm, mm->pgd);
966 * On resume, undo any pinning done at save, so that the rest of the
967 * kernel doesn't see any unexpected pinned pagetables.
969 void xen_mm_unpin_all(void)
973 spin_lock(&pgd_lock);
975 list_for_each_entry(page, &pgd_list, lru) {
976 if (PageSavePinned(page)) {
977 BUG_ON(!PagePinned(page));
978 __xen_pgd_unpin(&init_mm, (pgd_t *)page_address(page));
979 ClearPageSavePinned(page);
983 spin_unlock(&pgd_lock);
986 static void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
988 spin_lock(&next->page_table_lock);
990 spin_unlock(&next->page_table_lock);
993 static void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
995 spin_lock(&mm->page_table_lock);
997 spin_unlock(&mm->page_table_lock);
1002 /* Another cpu may still have their %cr3 pointing at the pagetable, so
1003 we need to repoint it somewhere else before we can unpin it. */
1004 static void drop_other_mm_ref(void *info)
1006 struct mm_struct *mm = info;
1007 struct mm_struct *active_mm;
1009 active_mm = this_cpu_read(cpu_tlbstate.active_mm);
1011 if (active_mm == mm && this_cpu_read(cpu_tlbstate.state) != TLBSTATE_OK)
1012 leave_mm(smp_processor_id());
1014 /* If this cpu still has a stale cr3 reference, then make sure
1015 it has been flushed. */
1016 if (this_cpu_read(xen_current_cr3) == __pa(mm->pgd))
1017 load_cr3(swapper_pg_dir);
1020 static void xen_drop_mm_ref(struct mm_struct *mm)
1025 if (current->active_mm == mm) {
1026 if (current->mm == mm)
1027 load_cr3(swapper_pg_dir);
1029 leave_mm(smp_processor_id());
1032 /* Get the "official" set of cpus referring to our pagetable. */
1033 if (!alloc_cpumask_var(&mask, GFP_ATOMIC)) {
1034 for_each_online_cpu(cpu) {
1035 if (!cpumask_test_cpu(cpu, mm_cpumask(mm))
1036 && per_cpu(xen_current_cr3, cpu) != __pa(mm->pgd))
1038 smp_call_function_single(cpu, drop_other_mm_ref, mm, 1);
1042 cpumask_copy(mask, mm_cpumask(mm));
1044 /* It's possible that a vcpu may have a stale reference to our
1045 cr3, because its in lazy mode, and it hasn't yet flushed
1046 its set of pending hypercalls yet. In this case, we can
1047 look at its actual current cr3 value, and force it to flush
1049 for_each_online_cpu(cpu) {
1050 if (per_cpu(xen_current_cr3, cpu) == __pa(mm->pgd))
1051 cpumask_set_cpu(cpu, mask);
1054 if (!cpumask_empty(mask))
1055 smp_call_function_many(mask, drop_other_mm_ref, mm, 1);
1056 free_cpumask_var(mask);
1059 static void xen_drop_mm_ref(struct mm_struct *mm)
1061 if (current->active_mm == mm)
1062 load_cr3(swapper_pg_dir);
1067 * While a process runs, Xen pins its pagetables, which means that the
1068 * hypervisor forces it to be read-only, and it controls all updates
1069 * to it. This means that all pagetable updates have to go via the
1070 * hypervisor, which is moderately expensive.
1072 * Since we're pulling the pagetable down, we switch to use init_mm,
1073 * unpin old process pagetable and mark it all read-write, which
1074 * allows further operations on it to be simple memory accesses.
1076 * The only subtle point is that another CPU may be still using the
1077 * pagetable because of lazy tlb flushing. This means we need need to
1078 * switch all CPUs off this pagetable before we can unpin it.
1080 static void xen_exit_mmap(struct mm_struct *mm)
1082 get_cpu(); /* make sure we don't move around */
1083 xen_drop_mm_ref(mm);
1086 spin_lock(&mm->page_table_lock);
1088 /* pgd may not be pinned in the error exit path of execve */
1089 if (xen_page_pinned(mm->pgd))
1092 spin_unlock(&mm->page_table_lock);
1095 static void xen_post_allocator_init(void);
1097 static void __init pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
1099 struct mmuext_op op;
1102 op.arg1.mfn = pfn_to_mfn(pfn);
1103 if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
1107 #ifdef CONFIG_X86_64
1108 static void __init xen_cleanhighmap(unsigned long vaddr,
1109 unsigned long vaddr_end)
1111 unsigned long kernel_end = roundup((unsigned long)_brk_end, PMD_SIZE) - 1;
1112 pmd_t *pmd = level2_kernel_pgt + pmd_index(vaddr);
1114 /* NOTE: The loop is more greedy than the cleanup_highmap variant.
1115 * We include the PMD passed in on _both_ boundaries. */
1116 for (; vaddr <= vaddr_end && (pmd < (level2_kernel_pgt + PTRS_PER_PMD));
1117 pmd++, vaddr += PMD_SIZE) {
1120 if (vaddr < (unsigned long) _text || vaddr > kernel_end)
1121 set_pmd(pmd, __pmd(0));
1123 /* In case we did something silly, we should crash in this function
1124 * instead of somewhere later and be confusing. */
1129 * Make a page range writeable and free it.
1131 static void __init xen_free_ro_pages(unsigned long paddr, unsigned long size)
1133 void *vaddr = __va(paddr);
1134 void *vaddr_end = vaddr + size;
1136 for (; vaddr < vaddr_end; vaddr += PAGE_SIZE)
1137 make_lowmem_page_readwrite(vaddr);
1139 memblock_free(paddr, size);
1142 static void __init xen_cleanmfnmap_free_pgtbl(void *pgtbl, bool unpin)
1144 unsigned long pa = __pa(pgtbl) & PHYSICAL_PAGE_MASK;
1147 pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(pa));
1148 ClearPagePinned(virt_to_page(__va(pa)));
1149 xen_free_ro_pages(pa, PAGE_SIZE);
1153 * Since it is well isolated we can (and since it is perhaps large we should)
1154 * also free the page tables mapping the initial P->M table.
1156 static void __init xen_cleanmfnmap(unsigned long vaddr)
1158 unsigned long va = vaddr & PMD_MASK;
1160 pgd_t *pgd = pgd_offset_k(va);
1161 pud_t *pud_page = pud_offset(pgd, 0);
1168 unpin = (vaddr == 2 * PGDIR_SIZE);
1169 set_pgd(pgd, __pgd(0));
1171 pud = pud_page + pud_index(va);
1172 if (pud_none(*pud)) {
1174 } else if (pud_large(*pud)) {
1175 pa = pud_val(*pud) & PHYSICAL_PAGE_MASK;
1176 xen_free_ro_pages(pa, PUD_SIZE);
1179 pmd = pmd_offset(pud, va);
1180 if (pmd_large(*pmd)) {
1181 pa = pmd_val(*pmd) & PHYSICAL_PAGE_MASK;
1182 xen_free_ro_pages(pa, PMD_SIZE);
1183 } else if (!pmd_none(*pmd)) {
1184 pte = pte_offset_kernel(pmd, va);
1185 set_pmd(pmd, __pmd(0));
1186 for (i = 0; i < PTRS_PER_PTE; ++i) {
1187 if (pte_none(pte[i]))
1189 pa = pte_pfn(pte[i]) << PAGE_SHIFT;
1190 xen_free_ro_pages(pa, PAGE_SIZE);
1192 xen_cleanmfnmap_free_pgtbl(pte, unpin);
1197 set_pud(pud, __pud(0));
1198 xen_cleanmfnmap_free_pgtbl(pmd, unpin);
1201 } while (pud_index(va) || pmd_index(va));
1202 xen_cleanmfnmap_free_pgtbl(pud_page, unpin);
1205 static void __init xen_pagetable_p2m_free(void)
1210 size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
1212 /* No memory or already called. */
1213 if ((unsigned long)xen_p2m_addr == xen_start_info->mfn_list)
1216 /* using __ka address and sticking INVALID_P2M_ENTRY! */
1217 memset((void *)xen_start_info->mfn_list, 0xff, size);
1219 addr = xen_start_info->mfn_list;
1221 * We could be in __ka space.
1222 * We roundup to the PMD, which means that if anybody at this stage is
1223 * using the __ka address of xen_start_info or
1224 * xen_start_info->shared_info they are in going to crash. Fortunatly
1225 * we have already revectored in xen_setup_kernel_pagetable and in
1226 * xen_setup_shared_info.
1228 size = roundup(size, PMD_SIZE);
1230 if (addr >= __START_KERNEL_map) {
1231 xen_cleanhighmap(addr, addr + size);
1232 size = PAGE_ALIGN(xen_start_info->nr_pages *
1233 sizeof(unsigned long));
1234 memblock_free(__pa(addr), size);
1236 xen_cleanmfnmap(addr);
1240 static void __init xen_pagetable_cleanhighmap(void)
1245 /* At this stage, cleanup_highmap has already cleaned __ka space
1246 * from _brk_limit way up to the max_pfn_mapped (which is the end of
1247 * the ramdisk). We continue on, erasing PMD entries that point to page
1248 * tables - do note that they are accessible at this stage via __va.
1249 * For good measure we also round up to the PMD - which means that if
1250 * anybody is using __ka address to the initial boot-stack - and try
1251 * to use it - they are going to crash. The xen_start_info has been
1252 * taken care of already in xen_setup_kernel_pagetable. */
1253 addr = xen_start_info->pt_base;
1254 size = roundup(xen_start_info->nr_pt_frames * PAGE_SIZE, PMD_SIZE);
1256 xen_cleanhighmap(addr, addr + size);
1257 xen_start_info->pt_base = (unsigned long)__va(__pa(xen_start_info->pt_base));
1259 /* This is superfluous and is not necessary, but you know what
1260 * lets do it. The MODULES_VADDR -> MODULES_END should be clear of
1261 * anything at this stage. */
1262 xen_cleanhighmap(MODULES_VADDR, roundup(MODULES_VADDR, PUD_SIZE) - 1);
1267 static void __init xen_pagetable_p2m_setup(void)
1269 if (xen_feature(XENFEAT_auto_translated_physmap))
1272 xen_vmalloc_p2m_tree();
1274 #ifdef CONFIG_X86_64
1275 xen_pagetable_p2m_free();
1277 xen_pagetable_cleanhighmap();
1279 /* And revector! Bye bye old array */
1280 xen_start_info->mfn_list = (unsigned long)xen_p2m_addr;
1283 static void __init xen_pagetable_init(void)
1286 xen_post_allocator_init();
1288 xen_pagetable_p2m_setup();
1290 /* Allocate and initialize top and mid mfn levels for p2m structure */
1291 xen_build_mfn_list_list();
1293 /* Remap memory freed due to conflicts with E820 map */
1294 if (!xen_feature(XENFEAT_auto_translated_physmap))
1297 xen_setup_shared_info();
1299 static void xen_write_cr2(unsigned long cr2)
1301 this_cpu_read(xen_vcpu)->arch.cr2 = cr2;
1304 static unsigned long xen_read_cr2(void)
1306 return this_cpu_read(xen_vcpu)->arch.cr2;
1309 unsigned long xen_read_cr2_direct(void)
1311 return this_cpu_read(xen_vcpu_info.arch.cr2);
1314 void xen_flush_tlb_all(void)
1316 struct mmuext_op *op;
1317 struct multicall_space mcs;
1319 trace_xen_mmu_flush_tlb_all(0);
1323 mcs = xen_mc_entry(sizeof(*op));
1326 op->cmd = MMUEXT_TLB_FLUSH_ALL;
1327 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
1329 xen_mc_issue(PARAVIRT_LAZY_MMU);
1333 static void xen_flush_tlb(void)
1335 struct mmuext_op *op;
1336 struct multicall_space mcs;
1338 trace_xen_mmu_flush_tlb(0);
1342 mcs = xen_mc_entry(sizeof(*op));
1345 op->cmd = MMUEXT_TLB_FLUSH_LOCAL;
1346 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
1348 xen_mc_issue(PARAVIRT_LAZY_MMU);
1353 static void xen_flush_tlb_single(unsigned long addr)
1355 struct mmuext_op *op;
1356 struct multicall_space mcs;
1358 trace_xen_mmu_flush_tlb_single(addr);
1362 mcs = xen_mc_entry(sizeof(*op));
1364 op->cmd = MMUEXT_INVLPG_LOCAL;
1365 op->arg1.linear_addr = addr & PAGE_MASK;
1366 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
1368 xen_mc_issue(PARAVIRT_LAZY_MMU);
1373 static void xen_flush_tlb_others(const struct cpumask *cpus,
1374 struct mm_struct *mm, unsigned long start,
1378 struct mmuext_op op;
1380 DECLARE_BITMAP(mask, num_processors);
1382 DECLARE_BITMAP(mask, NR_CPUS);
1385 struct multicall_space mcs;
1387 trace_xen_mmu_flush_tlb_others(cpus, mm, start, end);
1389 if (cpumask_empty(cpus))
1390 return; /* nothing to do */
1392 mcs = xen_mc_entry(sizeof(*args));
1394 args->op.arg2.vcpumask = to_cpumask(args->mask);
1396 /* Remove us, and any offline CPUS. */
1397 cpumask_and(to_cpumask(args->mask), cpus, cpu_online_mask);
1398 cpumask_clear_cpu(smp_processor_id(), to_cpumask(args->mask));
1400 args->op.cmd = MMUEXT_TLB_FLUSH_MULTI;
1401 if (end != TLB_FLUSH_ALL && (end - start) <= PAGE_SIZE) {
1402 args->op.cmd = MMUEXT_INVLPG_MULTI;
1403 args->op.arg1.linear_addr = start;
1406 MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF);
1408 xen_mc_issue(PARAVIRT_LAZY_MMU);
1411 static unsigned long xen_read_cr3(void)
1413 return this_cpu_read(xen_cr3);
1416 static void set_current_cr3(void *v)
1418 this_cpu_write(xen_current_cr3, (unsigned long)v);
1421 static void __xen_write_cr3(bool kernel, unsigned long cr3)
1423 struct mmuext_op op;
1426 trace_xen_mmu_write_cr3(kernel, cr3);
1429 mfn = pfn_to_mfn(PFN_DOWN(cr3));
1433 WARN_ON(mfn == 0 && kernel);
1435 op.cmd = kernel ? MMUEXT_NEW_BASEPTR : MMUEXT_NEW_USER_BASEPTR;
1438 xen_extend_mmuext_op(&op);
1441 this_cpu_write(xen_cr3, cr3);
1443 /* Update xen_current_cr3 once the batch has actually
1445 xen_mc_callback(set_current_cr3, (void *)cr3);
1448 static void xen_write_cr3(unsigned long cr3)
1450 BUG_ON(preemptible());
1452 xen_mc_batch(); /* disables interrupts */
1454 /* Update while interrupts are disabled, so its atomic with
1456 this_cpu_write(xen_cr3, cr3);
1458 __xen_write_cr3(true, cr3);
1460 #ifdef CONFIG_X86_64
1462 pgd_t *user_pgd = xen_get_user_pgd(__va(cr3));
1464 __xen_write_cr3(false, __pa(user_pgd));
1466 __xen_write_cr3(false, 0);
1470 xen_mc_issue(PARAVIRT_LAZY_CPU); /* interrupts restored */
1473 #ifdef CONFIG_X86_64
1475 * At the start of the day - when Xen launches a guest, it has already
1476 * built pagetables for the guest. We diligently look over them
1477 * in xen_setup_kernel_pagetable and graft as appropriate them in the
1478 * init_level4_pgt and its friends. Then when we are happy we load
1479 * the new init_level4_pgt - and continue on.
1481 * The generic code starts (start_kernel) and 'init_mem_mapping' sets
1482 * up the rest of the pagetables. When it has completed it loads the cr3.
1483 * N.B. that baremetal would start at 'start_kernel' (and the early
1484 * #PF handler would create bootstrap pagetables) - so we are running
1485 * with the same assumptions as what to do when write_cr3 is executed
1488 * Since there are no user-page tables at all, we have two variants
1489 * of xen_write_cr3 - the early bootup (this one), and the late one
1490 * (xen_write_cr3). The reason we have to do that is that in 64-bit
1491 * the Linux kernel and user-space are both in ring 3 while the
1492 * hypervisor is in ring 0.
1494 static void __init xen_write_cr3_init(unsigned long cr3)
1496 BUG_ON(preemptible());
1498 xen_mc_batch(); /* disables interrupts */
1500 /* Update while interrupts are disabled, so its atomic with
1502 this_cpu_write(xen_cr3, cr3);
1504 __xen_write_cr3(true, cr3);
1506 xen_mc_issue(PARAVIRT_LAZY_CPU); /* interrupts restored */
1510 static int xen_pgd_alloc(struct mm_struct *mm)
1512 pgd_t *pgd = mm->pgd;
1515 BUG_ON(PagePinned(virt_to_page(pgd)));
1517 #ifdef CONFIG_X86_64
1519 struct page *page = virt_to_page(pgd);
1522 BUG_ON(page->private != 0);
1526 user_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
1527 page->private = (unsigned long)user_pgd;
1529 if (user_pgd != NULL) {
1530 #ifdef CONFIG_X86_VSYSCALL_EMULATION
1531 user_pgd[pgd_index(VSYSCALL_ADDR)] =
1532 __pgd(__pa(level3_user_vsyscall) | _PAGE_TABLE);
1537 BUG_ON(PagePinned(virt_to_page(xen_get_user_pgd(pgd))));
1544 static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
1546 #ifdef CONFIG_X86_64
1547 pgd_t *user_pgd = xen_get_user_pgd(pgd);
1550 free_page((unsigned long)user_pgd);
1555 * Init-time set_pte while constructing initial pagetables, which
1556 * doesn't allow RO page table pages to be remapped RW.
1558 * If there is no MFN for this PFN then this page is initially
1559 * ballooned out so clear the PTE (as in decrease_reservation() in
1560 * drivers/xen/balloon.c).
1562 * Many of these PTE updates are done on unpinned and writable pages
1563 * and doing a hypercall for these is unnecessary and expensive. At
1564 * this point it is not possible to tell if a page is pinned or not,
1565 * so always write the PTE directly and rely on Xen trapping and
1566 * emulating any updates as necessary.
1568 __visible pte_t xen_make_pte_init(pteval_t pte)
1570 #ifdef CONFIG_X86_64
1574 * Pages belonging to the initial p2m list mapped outside the default
1575 * address range must be mapped read-only. This region contains the
1576 * page tables for mapping the p2m list, too, and page tables MUST be
1579 pfn = (pte & PTE_PFN_MASK) >> PAGE_SHIFT;
1580 if (xen_start_info->mfn_list < __START_KERNEL_map &&
1581 pfn >= xen_start_info->first_p2m_pfn &&
1582 pfn < xen_start_info->first_p2m_pfn + xen_start_info->nr_p2m_frames)
1585 pte = pte_pfn_to_mfn(pte);
1586 return native_make_pte(pte);
1588 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte_init);
1590 static void __init xen_set_pte_init(pte_t *ptep, pte_t pte)
1592 #ifdef CONFIG_X86_32
1593 /* If there's an existing pte, then don't allow _PAGE_RW to be set */
1594 if (pte_mfn(pte) != INVALID_P2M_ENTRY
1595 && pte_val_ma(*ptep) & _PAGE_PRESENT)
1596 pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) &
1599 native_set_pte(ptep, pte);
1602 /* Early in boot, while setting up the initial pagetable, assume
1603 everything is pinned. */
1604 static void __init xen_alloc_pte_init(struct mm_struct *mm, unsigned long pfn)
1606 #ifdef CONFIG_FLATMEM
1607 BUG_ON(mem_map); /* should only be used early */
1609 make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
1610 pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
1613 /* Used for pmd and pud */
1614 static void __init xen_alloc_pmd_init(struct mm_struct *mm, unsigned long pfn)
1616 #ifdef CONFIG_FLATMEM
1617 BUG_ON(mem_map); /* should only be used early */
1619 make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
1622 /* Early release_pte assumes that all pts are pinned, since there's
1623 only init_mm and anything attached to that is pinned. */
1624 static void __init xen_release_pte_init(unsigned long pfn)
1626 pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
1627 make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
1630 static void __init xen_release_pmd_init(unsigned long pfn)
1632 make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
1635 static inline void __pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
1637 struct multicall_space mcs;
1638 struct mmuext_op *op;
1640 mcs = __xen_mc_entry(sizeof(*op));
1643 op->arg1.mfn = pfn_to_mfn(pfn);
1645 MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
1648 static inline void __set_pfn_prot(unsigned long pfn, pgprot_t prot)
1650 struct multicall_space mcs;
1651 unsigned long addr = (unsigned long)__va(pfn << PAGE_SHIFT);
1653 mcs = __xen_mc_entry(0);
1654 MULTI_update_va_mapping(mcs.mc, (unsigned long)addr,
1655 pfn_pte(pfn, prot), 0);
1658 /* This needs to make sure the new pte page is pinned iff its being
1659 attached to a pinned pagetable. */
1660 static inline void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn,
1663 bool pinned = PagePinned(virt_to_page(mm->pgd));
1665 trace_xen_mmu_alloc_ptpage(mm, pfn, level, pinned);
1668 struct page *page = pfn_to_page(pfn);
1670 SetPagePinned(page);
1672 if (!PageHighMem(page)) {
1675 __set_pfn_prot(pfn, PAGE_KERNEL_RO);
1677 if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS)
1678 __pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
1680 xen_mc_issue(PARAVIRT_LAZY_MMU);
1682 /* make sure there are no stray mappings of
1684 kmap_flush_unused();
1689 static void xen_alloc_pte(struct mm_struct *mm, unsigned long pfn)
1691 xen_alloc_ptpage(mm, pfn, PT_PTE);
1694 static void xen_alloc_pmd(struct mm_struct *mm, unsigned long pfn)
1696 xen_alloc_ptpage(mm, pfn, PT_PMD);
1699 /* This should never happen until we're OK to use struct page */
1700 static inline void xen_release_ptpage(unsigned long pfn, unsigned level)
1702 struct page *page = pfn_to_page(pfn);
1703 bool pinned = PagePinned(page);
1705 trace_xen_mmu_release_ptpage(pfn, level, pinned);
1708 if (!PageHighMem(page)) {
1711 if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS)
1712 __pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
1714 __set_pfn_prot(pfn, PAGE_KERNEL);
1716 xen_mc_issue(PARAVIRT_LAZY_MMU);
1718 ClearPagePinned(page);
1722 static void xen_release_pte(unsigned long pfn)
1724 xen_release_ptpage(pfn, PT_PTE);
1727 static void xen_release_pmd(unsigned long pfn)
1729 xen_release_ptpage(pfn, PT_PMD);
1732 #if CONFIG_PGTABLE_LEVELS == 4
1733 static void xen_alloc_pud(struct mm_struct *mm, unsigned long pfn)
1735 xen_alloc_ptpage(mm, pfn, PT_PUD);
1738 static void xen_release_pud(unsigned long pfn)
1740 xen_release_ptpage(pfn, PT_PUD);
1744 void __init xen_reserve_top(void)
1746 #ifdef CONFIG_X86_32
1747 unsigned long top = HYPERVISOR_VIRT_START;
1748 struct xen_platform_parameters pp;
1750 if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0)
1751 top = pp.virt_start;
1753 reserve_top_address(-top);
1754 #endif /* CONFIG_X86_32 */
1758 * Like __va(), but returns address in the kernel mapping (which is
1759 * all we have until the physical memory mapping has been set up.
1761 static void * __init __ka(phys_addr_t paddr)
1763 #ifdef CONFIG_X86_64
1764 return (void *)(paddr + __START_KERNEL_map);
1770 /* Convert a machine address to physical address */
1771 static unsigned long __init m2p(phys_addr_t maddr)
1775 maddr &= PTE_PFN_MASK;
1776 paddr = mfn_to_pfn(maddr >> PAGE_SHIFT) << PAGE_SHIFT;
1781 /* Convert a machine address to kernel virtual */
1782 static void * __init m2v(phys_addr_t maddr)
1784 return __ka(m2p(maddr));
1787 /* Set the page permissions on an identity-mapped pages */
1788 static void __init set_page_prot_flags(void *addr, pgprot_t prot,
1789 unsigned long flags)
1791 unsigned long pfn = __pa(addr) >> PAGE_SHIFT;
1792 pte_t pte = pfn_pte(pfn, prot);
1794 /* For PVH no need to set R/O or R/W to pin them or unpin them. */
1795 if (xen_feature(XENFEAT_auto_translated_physmap))
1798 if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, flags))
1801 static void __init set_page_prot(void *addr, pgprot_t prot)
1803 return set_page_prot_flags(addr, prot, UVMF_NONE);
1805 #ifdef CONFIG_X86_32
1806 static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
1808 unsigned pmdidx, pteidx;
1812 level1_ident_pgt = extend_brk(sizeof(pte_t) * LEVEL1_IDENT_ENTRIES,
1817 for (pmdidx = 0; pmdidx < PTRS_PER_PMD && pfn < max_pfn; pmdidx++) {
1820 /* Reuse or allocate a page of ptes */
1821 if (pmd_present(pmd[pmdidx]))
1822 pte_page = m2v(pmd[pmdidx].pmd);
1824 /* Check for free pte pages */
1825 if (ident_pte == LEVEL1_IDENT_ENTRIES)
1828 pte_page = &level1_ident_pgt[ident_pte];
1829 ident_pte += PTRS_PER_PTE;
1831 pmd[pmdidx] = __pmd(__pa(pte_page) | _PAGE_TABLE);
1834 /* Install mappings */
1835 for (pteidx = 0; pteidx < PTRS_PER_PTE; pteidx++, pfn++) {
1838 if (pfn > max_pfn_mapped)
1839 max_pfn_mapped = pfn;
1841 if (!pte_none(pte_page[pteidx]))
1844 pte = pfn_pte(pfn, PAGE_KERNEL_EXEC);
1845 pte_page[pteidx] = pte;
1849 for (pteidx = 0; pteidx < ident_pte; pteidx += PTRS_PER_PTE)
1850 set_page_prot(&level1_ident_pgt[pteidx], PAGE_KERNEL_RO);
1852 set_page_prot(pmd, PAGE_KERNEL_RO);
1855 void __init xen_setup_machphys_mapping(void)
1857 struct xen_machphys_mapping mapping;
1859 if (HYPERVISOR_memory_op(XENMEM_machphys_mapping, &mapping) == 0) {
1860 machine_to_phys_mapping = (unsigned long *)mapping.v_start;
1861 machine_to_phys_nr = mapping.max_mfn + 1;
1863 machine_to_phys_nr = MACH2PHYS_NR_ENTRIES;
1865 #ifdef CONFIG_X86_32
1866 WARN_ON((machine_to_phys_mapping + (machine_to_phys_nr - 1))
1867 < machine_to_phys_mapping);
1871 #ifdef CONFIG_X86_64
1872 static void __init convert_pfn_mfn(void *v)
1877 /* All levels are converted the same way, so just treat them
1879 for (i = 0; i < PTRS_PER_PTE; i++)
1880 pte[i] = xen_make_pte(pte[i].pte);
1882 static void __init check_pt_base(unsigned long *pt_base, unsigned long *pt_end,
1885 if (*pt_base == PFN_DOWN(__pa(addr))) {
1886 set_page_prot_flags((void *)addr, PAGE_KERNEL, UVMF_INVLPG);
1887 clear_page((void *)addr);
1890 if (*pt_end == PFN_DOWN(__pa(addr))) {
1891 set_page_prot_flags((void *)addr, PAGE_KERNEL, UVMF_INVLPG);
1892 clear_page((void *)addr);
1897 * Set up the initial kernel pagetable.
1899 * We can construct this by grafting the Xen provided pagetable into
1900 * head_64.S's preconstructed pagetables. We copy the Xen L2's into
1901 * level2_ident_pgt, and level2_kernel_pgt. This means that only the
1902 * kernel has a physical mapping to start with - but that's enough to
1903 * get __va working. We need to fill in the rest of the physical
1904 * mapping once some sort of allocator has been set up. NOTE: for
1905 * PVH, the page tables are native.
1907 void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
1911 unsigned long addr[3];
1912 unsigned long pt_base, pt_end;
1915 /* max_pfn_mapped is the last pfn mapped in the initial memory
1916 * mappings. Considering that on Xen after the kernel mappings we
1917 * have the mappings of some pages that don't exist in pfn space, we
1918 * set max_pfn_mapped to the last real pfn mapped. */
1919 if (xen_start_info->mfn_list < __START_KERNEL_map)
1920 max_pfn_mapped = xen_start_info->first_p2m_pfn;
1922 max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));
1924 pt_base = PFN_DOWN(__pa(xen_start_info->pt_base));
1925 pt_end = pt_base + xen_start_info->nr_pt_frames;
1927 /* Zap identity mapping */
1928 init_level4_pgt[0] = __pgd(0);
1930 if (!xen_feature(XENFEAT_auto_translated_physmap)) {
1931 /* Pre-constructed entries are in pfn, so convert to mfn */
1932 /* L4[272] -> level3_ident_pgt
1933 * L4[511] -> level3_kernel_pgt */
1934 convert_pfn_mfn(init_level4_pgt);
1936 /* L3_i[0] -> level2_ident_pgt */
1937 convert_pfn_mfn(level3_ident_pgt);
1938 /* L3_k[510] -> level2_kernel_pgt
1939 * L3_k[511] -> level2_fixmap_pgt */
1940 convert_pfn_mfn(level3_kernel_pgt);
1942 /* L3_k[511][506] -> level1_fixmap_pgt */
1943 convert_pfn_mfn(level2_fixmap_pgt);
1945 /* We get [511][511] and have Xen's version of level2_kernel_pgt */
1946 l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd);
1947 l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud);
1949 addr[0] = (unsigned long)pgd;
1950 addr[1] = (unsigned long)l3;
1951 addr[2] = (unsigned long)l2;
1952 /* Graft it onto L4[272][0]. Note that we creating an aliasing problem:
1953 * Both L4[272][0] and L4[511][510] have entries that point to the same
1954 * L2 (PMD) tables. Meaning that if you modify it in __va space
1955 * it will be also modified in the __ka space! (But if you just
1956 * modify the PMD table to point to other PTE's or none, then you
1957 * are OK - which is what cleanup_highmap does) */
1958 copy_page(level2_ident_pgt, l2);
1959 /* Graft it onto L4[511][510] */
1960 copy_page(level2_kernel_pgt, l2);
1962 /* Copy the initial P->M table mappings if necessary. */
1963 i = pgd_index(xen_start_info->mfn_list);
1964 if (i && i < pgd_index(__START_KERNEL_map))
1965 init_level4_pgt[i] = ((pgd_t *)xen_start_info->pt_base)[i];
1967 if (!xen_feature(XENFEAT_auto_translated_physmap)) {
1968 /* Make pagetable pieces RO */
1969 set_page_prot(init_level4_pgt, PAGE_KERNEL_RO);
1970 set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO);
1971 set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO);
1972 set_page_prot(level3_user_vsyscall, PAGE_KERNEL_RO);
1973 set_page_prot(level2_ident_pgt, PAGE_KERNEL_RO);
1974 set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
1975 set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO);
1976 set_page_prot(level1_fixmap_pgt, PAGE_KERNEL_RO);
1978 /* Pin down new L4 */
1979 pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE,
1980 PFN_DOWN(__pa_symbol(init_level4_pgt)));
1982 /* Unpin Xen-provided one */
1983 pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
1986 * At this stage there can be no user pgd, and no page
1987 * structure to attach it to, so make sure we just set kernel
1991 __xen_write_cr3(true, __pa(init_level4_pgt));
1992 xen_mc_issue(PARAVIRT_LAZY_CPU);
1994 native_write_cr3(__pa(init_level4_pgt));
1996 /* We can't that easily rip out L3 and L2, as the Xen pagetables are
1997 * set out this way: [L4], [L1], [L2], [L3], [L1], [L1] ... for
1998 * the initial domain. For guests using the toolstack, they are in:
1999 * [L4], [L3], [L2], [L1], [L1], order .. So for dom0 we can only
2000 * rip out the [L4] (pgd), but for guests we shave off three pages.
2002 for (i = 0; i < ARRAY_SIZE(addr); i++)
2003 check_pt_base(&pt_base, &pt_end, addr[i]);
2005 /* Our (by three pages) smaller Xen pagetable that we are using */
2006 xen_pt_base = PFN_PHYS(pt_base);
2007 xen_pt_size = (pt_end - pt_base) * PAGE_SIZE;
2008 memblock_reserve(xen_pt_base, xen_pt_size);
2010 /* Revector the xen_start_info */
2011 xen_start_info = (struct start_info *)__va(__pa(xen_start_info));
2015 * Read a value from a physical address.
2017 static unsigned long __init xen_read_phys_ulong(phys_addr_t addr)
2019 unsigned long *vaddr;
2022 vaddr = early_memremap_ro(addr, sizeof(val));
2024 early_memunmap(vaddr, sizeof(val));
2029 * Translate a virtual address to a physical one without relying on mapped
2032 static phys_addr_t __init xen_early_virt_to_phys(unsigned long vaddr)
2041 pgd = native_make_pgd(xen_read_phys_ulong(pa + pgd_index(vaddr) *
2043 if (!pgd_present(pgd))
2046 pa = pgd_val(pgd) & PTE_PFN_MASK;
2047 pud = native_make_pud(xen_read_phys_ulong(pa + pud_index(vaddr) *
2049 if (!pud_present(pud))
2051 pa = pud_pfn(pud) << PAGE_SHIFT;
2053 return pa + (vaddr & ~PUD_MASK);
2055 pmd = native_make_pmd(xen_read_phys_ulong(pa + pmd_index(vaddr) *
2057 if (!pmd_present(pmd))
2059 pa = pmd_pfn(pmd) << PAGE_SHIFT;
2061 return pa + (vaddr & ~PMD_MASK);
2063 pte = native_make_pte(xen_read_phys_ulong(pa + pte_index(vaddr) *
2065 if (!pte_present(pte))
2067 pa = pte_pfn(pte) << PAGE_SHIFT;
2069 return pa | (vaddr & ~PAGE_MASK);
2073 * Find a new area for the hypervisor supplied p2m list and relocate the p2m to
2076 void __init xen_relocate_p2m(void)
2078 phys_addr_t size, new_area, pt_phys, pmd_phys, pud_phys;
2079 unsigned long p2m_pfn, p2m_pfn_end, n_frames, pfn, pfn_end;
2080 int n_pte, n_pt, n_pmd, n_pud, idx_pte, idx_pt, idx_pmd, idx_pud;
2085 unsigned long *new_p2m;
2087 size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
2088 n_pte = roundup(size, PAGE_SIZE) >> PAGE_SHIFT;
2089 n_pt = roundup(size, PMD_SIZE) >> PMD_SHIFT;
2090 n_pmd = roundup(size, PUD_SIZE) >> PUD_SHIFT;
2091 n_pud = roundup(size, PGDIR_SIZE) >> PGDIR_SHIFT;
2092 n_frames = n_pte + n_pt + n_pmd + n_pud;
2094 new_area = xen_find_free_area(PFN_PHYS(n_frames));
2096 xen_raw_console_write("Can't find new memory area for p2m needed due to E820 map conflict\n");
2101 * Setup the page tables for addressing the new p2m list.
2102 * We have asked the hypervisor to map the p2m list at the user address
2103 * PUD_SIZE. It may have done so, or it may have used a kernel space
2104 * address depending on the Xen version.
2105 * To avoid any possible virtual address collision, just use
2106 * 2 * PUD_SIZE for the new area.
2108 pud_phys = new_area;
2109 pmd_phys = pud_phys + PFN_PHYS(n_pud);
2110 pt_phys = pmd_phys + PFN_PHYS(n_pmd);
2111 p2m_pfn = PFN_DOWN(pt_phys) + n_pt;
2113 pgd = __va(read_cr3());
2114 new_p2m = (unsigned long *)(2 * PGDIR_SIZE);
2115 for (idx_pud = 0; idx_pud < n_pud; idx_pud++) {
2116 pud = early_memremap(pud_phys, PAGE_SIZE);
2118 for (idx_pmd = 0; idx_pmd < min(n_pmd, PTRS_PER_PUD);
2120 pmd = early_memremap(pmd_phys, PAGE_SIZE);
2122 for (idx_pt = 0; idx_pt < min(n_pt, PTRS_PER_PMD);
2124 pt = early_memremap(pt_phys, PAGE_SIZE);
2127 idx_pte < min(n_pte, PTRS_PER_PTE);
2129 set_pte(pt + idx_pte,
2130 pfn_pte(p2m_pfn, PAGE_KERNEL));
2133 n_pte -= PTRS_PER_PTE;
2134 early_memunmap(pt, PAGE_SIZE);
2135 make_lowmem_page_readonly(__va(pt_phys));
2136 pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE,
2138 set_pmd(pmd + idx_pt,
2139 __pmd(_PAGE_TABLE | pt_phys));
2140 pt_phys += PAGE_SIZE;
2142 n_pt -= PTRS_PER_PMD;
2143 early_memunmap(pmd, PAGE_SIZE);
2144 make_lowmem_page_readonly(__va(pmd_phys));
2145 pin_pagetable_pfn(MMUEXT_PIN_L2_TABLE,
2146 PFN_DOWN(pmd_phys));
2147 set_pud(pud + idx_pmd, __pud(_PAGE_TABLE | pmd_phys));
2148 pmd_phys += PAGE_SIZE;
2150 n_pmd -= PTRS_PER_PUD;
2151 early_memunmap(pud, PAGE_SIZE);
2152 make_lowmem_page_readonly(__va(pud_phys));
2153 pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, PFN_DOWN(pud_phys));
2154 set_pgd(pgd + 2 + idx_pud, __pgd(_PAGE_TABLE | pud_phys));
2155 pud_phys += PAGE_SIZE;
2158 /* Now copy the old p2m info to the new area. */
2159 memcpy(new_p2m, xen_p2m_addr, size);
2160 xen_p2m_addr = new_p2m;
2162 /* Release the old p2m list and set new list info. */
2163 p2m_pfn = PFN_DOWN(xen_early_virt_to_phys(xen_start_info->mfn_list));
2165 p2m_pfn_end = p2m_pfn + PFN_DOWN(size);
2167 if (xen_start_info->mfn_list < __START_KERNEL_map) {
2168 pfn = xen_start_info->first_p2m_pfn;
2169 pfn_end = xen_start_info->first_p2m_pfn +
2170 xen_start_info->nr_p2m_frames;
2171 set_pgd(pgd + 1, __pgd(0));
2174 pfn_end = p2m_pfn_end;
2177 memblock_free(PFN_PHYS(pfn), PAGE_SIZE * (pfn_end - pfn));
2178 while (pfn < pfn_end) {
2179 if (pfn == p2m_pfn) {
2183 make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
2187 xen_start_info->mfn_list = (unsigned long)xen_p2m_addr;
2188 xen_start_info->first_p2m_pfn = PFN_DOWN(new_area);
2189 xen_start_info->nr_p2m_frames = n_frames;
2192 #else /* !CONFIG_X86_64 */
2193 static RESERVE_BRK_ARRAY(pmd_t, initial_kernel_pmd, PTRS_PER_PMD);
2194 static RESERVE_BRK_ARRAY(pmd_t, swapper_kernel_pmd, PTRS_PER_PMD);
2196 static void __init xen_write_cr3_init(unsigned long cr3)
2198 unsigned long pfn = PFN_DOWN(__pa(swapper_pg_dir));
2200 BUG_ON(read_cr3() != __pa(initial_page_table));
2201 BUG_ON(cr3 != __pa(swapper_pg_dir));
2204 * We are switching to swapper_pg_dir for the first time (from
2205 * initial_page_table) and therefore need to mark that page
2206 * read-only and then pin it.
2208 * Xen disallows sharing of kernel PMDs for PAE
2209 * guests. Therefore we must copy the kernel PMD from
2210 * initial_page_table into a new kernel PMD to be used in
2213 swapper_kernel_pmd =
2214 extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
2215 copy_page(swapper_kernel_pmd, initial_kernel_pmd);
2216 swapper_pg_dir[KERNEL_PGD_BOUNDARY] =
2217 __pgd(__pa(swapper_kernel_pmd) | _PAGE_PRESENT);
2218 set_page_prot(swapper_kernel_pmd, PAGE_KERNEL_RO);
2220 set_page_prot(swapper_pg_dir, PAGE_KERNEL_RO);
2222 pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, pfn);
2224 pin_pagetable_pfn(MMUEXT_UNPIN_TABLE,
2225 PFN_DOWN(__pa(initial_page_table)));
2226 set_page_prot(initial_page_table, PAGE_KERNEL);
2227 set_page_prot(initial_kernel_pmd, PAGE_KERNEL);
2229 pv_mmu_ops.write_cr3 = &xen_write_cr3;
2233 * For 32 bit domains xen_start_info->pt_base is the pgd address which might be
2234 * not the first page table in the page table pool.
2235 * Iterate through the initial page tables to find the real page table base.
2237 static phys_addr_t xen_find_pt_base(pmd_t *pmd)
2239 phys_addr_t pt_base, paddr;
2242 pt_base = min(__pa(xen_start_info->pt_base), __pa(pmd));
2244 for (pmdidx = 0; pmdidx < PTRS_PER_PMD; pmdidx++)
2245 if (pmd_present(pmd[pmdidx]) && !pmd_large(pmd[pmdidx])) {
2246 paddr = m2p(pmd[pmdidx].pmd);
2247 pt_base = min(pt_base, paddr);
2253 void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
2257 kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
2259 xen_pt_base = xen_find_pt_base(kernel_pmd);
2260 xen_pt_size = xen_start_info->nr_pt_frames * PAGE_SIZE;
2262 initial_kernel_pmd =
2263 extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
2265 max_pfn_mapped = PFN_DOWN(xen_pt_base + xen_pt_size + 512 * 1024);
2267 copy_page(initial_kernel_pmd, kernel_pmd);
2269 xen_map_identity_early(initial_kernel_pmd, max_pfn);
2271 copy_page(initial_page_table, pgd);
2272 initial_page_table[KERNEL_PGD_BOUNDARY] =
2273 __pgd(__pa(initial_kernel_pmd) | _PAGE_PRESENT);
2275 set_page_prot(initial_kernel_pmd, PAGE_KERNEL_RO);
2276 set_page_prot(initial_page_table, PAGE_KERNEL_RO);
2277 set_page_prot(empty_zero_page, PAGE_KERNEL_RO);
2279 pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
2281 pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE,
2282 PFN_DOWN(__pa(initial_page_table)));
2283 xen_write_cr3(__pa(initial_page_table));
2285 memblock_reserve(xen_pt_base, xen_pt_size);
2287 #endif /* CONFIG_X86_64 */
2289 void __init xen_reserve_special_pages(void)
2293 memblock_reserve(__pa(xen_start_info), PAGE_SIZE);
2294 if (xen_start_info->store_mfn) {
2295 paddr = PFN_PHYS(mfn_to_pfn(xen_start_info->store_mfn));
2296 memblock_reserve(paddr, PAGE_SIZE);
2298 if (!xen_initial_domain()) {
2299 paddr = PFN_PHYS(mfn_to_pfn(xen_start_info->console.domU.mfn));
2300 memblock_reserve(paddr, PAGE_SIZE);
2304 void __init xen_pt_check_e820(void)
2306 if (xen_is_e820_reserved(xen_pt_base, xen_pt_size)) {
2307 xen_raw_console_write("Xen hypervisor allocated page table memory conflicts with E820 map\n");
2312 static unsigned char dummy_mapping[PAGE_SIZE] __page_aligned_bss;
2314 static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
2318 phys >>= PAGE_SHIFT;
2321 case FIX_BTMAP_END ... FIX_BTMAP_BEGIN:
2323 #ifdef CONFIG_X86_32
2325 # ifdef CONFIG_HIGHMEM
2326 case FIX_KMAP_BEGIN ... FIX_KMAP_END:
2328 #elif defined(CONFIG_X86_VSYSCALL_EMULATION)
2331 case FIX_TEXT_POKE0:
2332 case FIX_TEXT_POKE1:
2333 /* All local page mappings */
2334 pte = pfn_pte(phys, prot);
2337 #ifdef CONFIG_X86_LOCAL_APIC
2338 case FIX_APIC_BASE: /* maps dummy local APIC */
2339 pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
2343 #ifdef CONFIG_X86_IO_APIC
2344 case FIX_IO_APIC_BASE_0 ... FIX_IO_APIC_BASE_END:
2346 * We just don't map the IO APIC - all access is via
2347 * hypercalls. Keep the address in the pte for reference.
2349 pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
2353 case FIX_PARAVIRT_BOOTMAP:
2354 /* This is an MFN, but it isn't an IO mapping from the
2356 pte = mfn_pte(phys, prot);
2360 /* By default, set_fixmap is used for hardware mappings */
2361 pte = mfn_pte(phys, prot);
2365 __native_set_fixmap(idx, pte);
2367 #ifdef CONFIG_X86_VSYSCALL_EMULATION
2368 /* Replicate changes to map the vsyscall page into the user
2369 pagetable vsyscall mapping. */
2370 if (idx == VSYSCALL_PAGE) {
2371 unsigned long vaddr = __fix_to_virt(idx);
2372 set_pte_vaddr_pud(level3_user_vsyscall, vaddr, pte);
2377 static void __init xen_post_allocator_init(void)
2379 if (xen_feature(XENFEAT_auto_translated_physmap))
2382 pv_mmu_ops.set_pte = xen_set_pte;
2383 pv_mmu_ops.set_pmd = xen_set_pmd;
2384 pv_mmu_ops.set_pud = xen_set_pud;
2385 #if CONFIG_PGTABLE_LEVELS == 4
2386 pv_mmu_ops.set_pgd = xen_set_pgd;
2389 /* This will work as long as patching hasn't happened yet
2390 (which it hasn't) */
2391 pv_mmu_ops.alloc_pte = xen_alloc_pte;
2392 pv_mmu_ops.alloc_pmd = xen_alloc_pmd;
2393 pv_mmu_ops.release_pte = xen_release_pte;
2394 pv_mmu_ops.release_pmd = xen_release_pmd;
2395 #if CONFIG_PGTABLE_LEVELS == 4
2396 pv_mmu_ops.alloc_pud = xen_alloc_pud;
2397 pv_mmu_ops.release_pud = xen_release_pud;
2399 pv_mmu_ops.make_pte = PV_CALLEE_SAVE(xen_make_pte);
2401 #ifdef CONFIG_X86_64
2402 pv_mmu_ops.write_cr3 = &xen_write_cr3;
2403 SetPagePinned(virt_to_page(level3_user_vsyscall));
2405 xen_mark_init_mm_pinned();
2408 static void xen_leave_lazy_mmu(void)
2412 paravirt_leave_lazy_mmu();
2416 static const struct pv_mmu_ops xen_mmu_ops __initconst = {
2417 .read_cr2 = xen_read_cr2,
2418 .write_cr2 = xen_write_cr2,
2420 .read_cr3 = xen_read_cr3,
2421 .write_cr3 = xen_write_cr3_init,
2423 .flush_tlb_user = xen_flush_tlb,
2424 .flush_tlb_kernel = xen_flush_tlb,
2425 .flush_tlb_single = xen_flush_tlb_single,
2426 .flush_tlb_others = xen_flush_tlb_others,
2428 .pte_update = paravirt_nop,
2430 .pgd_alloc = xen_pgd_alloc,
2431 .pgd_free = xen_pgd_free,
2433 .alloc_pte = xen_alloc_pte_init,
2434 .release_pte = xen_release_pte_init,
2435 .alloc_pmd = xen_alloc_pmd_init,
2436 .release_pmd = xen_release_pmd_init,
2438 .set_pte = xen_set_pte_init,
2439 .set_pte_at = xen_set_pte_at,
2440 .set_pmd = xen_set_pmd_hyper,
2442 .ptep_modify_prot_start = __ptep_modify_prot_start,
2443 .ptep_modify_prot_commit = __ptep_modify_prot_commit,
2445 .pte_val = PV_CALLEE_SAVE(xen_pte_val),
2446 .pgd_val = PV_CALLEE_SAVE(xen_pgd_val),
2448 .make_pte = PV_CALLEE_SAVE(xen_make_pte_init),
2449 .make_pgd = PV_CALLEE_SAVE(xen_make_pgd),
2451 #ifdef CONFIG_X86_PAE
2452 .set_pte_atomic = xen_set_pte_atomic,
2453 .pte_clear = xen_pte_clear,
2454 .pmd_clear = xen_pmd_clear,
2455 #endif /* CONFIG_X86_PAE */
2456 .set_pud = xen_set_pud_hyper,
2458 .make_pmd = PV_CALLEE_SAVE(xen_make_pmd),
2459 .pmd_val = PV_CALLEE_SAVE(xen_pmd_val),
2461 #if CONFIG_PGTABLE_LEVELS == 4
2462 .pud_val = PV_CALLEE_SAVE(xen_pud_val),
2463 .make_pud = PV_CALLEE_SAVE(xen_make_pud),
2464 .set_pgd = xen_set_pgd_hyper,
2466 .alloc_pud = xen_alloc_pmd_init,
2467 .release_pud = xen_release_pmd_init,
2468 #endif /* CONFIG_PGTABLE_LEVELS == 4 */
2470 .activate_mm = xen_activate_mm,
2471 .dup_mmap = xen_dup_mmap,
2472 .exit_mmap = xen_exit_mmap,
2475 .enter = paravirt_enter_lazy_mmu,
2476 .leave = xen_leave_lazy_mmu,
2477 .flush = paravirt_flush_lazy_mmu,
2480 .set_fixmap = xen_set_fixmap,
2483 void __init xen_init_mmu_ops(void)
2485 x86_init.paging.pagetable_init = xen_pagetable_init;
2487 if (xen_feature(XENFEAT_auto_translated_physmap))
2490 pv_mmu_ops = xen_mmu_ops;
2492 memset(dummy_mapping, 0xff, PAGE_SIZE);
2495 /* Protected by xen_reservation_lock. */
2496 #define MAX_CONTIG_ORDER 9 /* 2MB */
2497 static unsigned long discontig_frames[1<<MAX_CONTIG_ORDER];
2499 #define VOID_PTE (mfn_pte(0, __pgprot(0)))
2500 static void xen_zap_pfn_range(unsigned long vaddr, unsigned int order,
2501 unsigned long *in_frames,
2502 unsigned long *out_frames)
2505 struct multicall_space mcs;
2508 for (i = 0; i < (1UL<<order); i++, vaddr += PAGE_SIZE) {
2509 mcs = __xen_mc_entry(0);
2512 in_frames[i] = virt_to_mfn(vaddr);
2514 MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0);
2515 __set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);
2518 out_frames[i] = virt_to_pfn(vaddr);
2524 * Update the pfn-to-mfn mappings for a virtual address range, either to
2525 * point to an array of mfns, or contiguously from a single starting
2528 static void xen_remap_exchanged_ptes(unsigned long vaddr, int order,
2529 unsigned long *mfns,
2530 unsigned long first_mfn)
2537 limit = 1u << order;
2538 for (i = 0; i < limit; i++, vaddr += PAGE_SIZE) {
2539 struct multicall_space mcs;
2542 mcs = __xen_mc_entry(0);
2546 mfn = first_mfn + i;
2548 if (i < (limit - 1))
2552 flags = UVMF_INVLPG | UVMF_ALL;
2554 flags = UVMF_TLB_FLUSH | UVMF_ALL;
2557 MULTI_update_va_mapping(mcs.mc, vaddr,
2558 mfn_pte(mfn, PAGE_KERNEL), flags);
2560 set_phys_to_machine(virt_to_pfn(vaddr), mfn);
2567 * Perform the hypercall to exchange a region of our pfns to point to
2568 * memory with the required contiguous alignment. Takes the pfns as
2569 * input, and populates mfns as output.
2571 * Returns a success code indicating whether the hypervisor was able to
2572 * satisfy the request or not.
2574 static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in,
2575 unsigned long *pfns_in,
2576 unsigned long extents_out,
2577 unsigned int order_out,
2578 unsigned long *mfns_out,
2579 unsigned int address_bits)
2584 struct xen_memory_exchange exchange = {
2586 .nr_extents = extents_in,
2587 .extent_order = order_in,
2588 .extent_start = pfns_in,
2592 .nr_extents = extents_out,
2593 .extent_order = order_out,
2594 .extent_start = mfns_out,
2595 .address_bits = address_bits,
2600 BUG_ON(extents_in << order_in != extents_out << order_out);
2602 rc = HYPERVISOR_memory_op(XENMEM_exchange, &exchange);
2603 success = (exchange.nr_exchanged == extents_in);
2605 BUG_ON(!success && ((exchange.nr_exchanged != 0) || (rc == 0)));
2606 BUG_ON(success && (rc != 0));
2611 int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
2612 unsigned int address_bits,
2613 dma_addr_t *dma_handle)
2615 unsigned long *in_frames = discontig_frames, out_frame;
2616 unsigned long flags;
2618 unsigned long vstart = (unsigned long)phys_to_virt(pstart);
2621 * Currently an auto-translated guest will not perform I/O, nor will
2622 * it require PAE page directories below 4GB. Therefore any calls to
2623 * this function are redundant and can be ignored.
2626 if (xen_feature(XENFEAT_auto_translated_physmap))
2629 if (unlikely(order > MAX_CONTIG_ORDER))
2632 memset((void *) vstart, 0, PAGE_SIZE << order);
2634 spin_lock_irqsave(&xen_reservation_lock, flags);
2636 /* 1. Zap current PTEs, remembering MFNs. */
2637 xen_zap_pfn_range(vstart, order, in_frames, NULL);
2639 /* 2. Get a new contiguous memory extent. */
2640 out_frame = virt_to_pfn(vstart);
2641 success = xen_exchange_memory(1UL << order, 0, in_frames,
2642 1, order, &out_frame,
2645 /* 3. Map the new extent in place of old pages. */
2647 xen_remap_exchanged_ptes(vstart, order, NULL, out_frame);
2649 xen_remap_exchanged_ptes(vstart, order, in_frames, 0);
2651 spin_unlock_irqrestore(&xen_reservation_lock, flags);
2653 *dma_handle = virt_to_machine(vstart).maddr;
2654 return success ? 0 : -ENOMEM;
2656 EXPORT_SYMBOL_GPL(xen_create_contiguous_region);
2658 void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)
2660 unsigned long *out_frames = discontig_frames, in_frame;
2661 unsigned long flags;
2663 unsigned long vstart;
2665 if (xen_feature(XENFEAT_auto_translated_physmap))
2668 if (unlikely(order > MAX_CONTIG_ORDER))
2671 vstart = (unsigned long)phys_to_virt(pstart);
2672 memset((void *) vstart, 0, PAGE_SIZE << order);
2674 spin_lock_irqsave(&xen_reservation_lock, flags);
2676 /* 1. Find start MFN of contiguous extent. */
2677 in_frame = virt_to_mfn(vstart);
2679 /* 2. Zap current PTEs. */
2680 xen_zap_pfn_range(vstart, order, NULL, out_frames);
2682 /* 3. Do the exchange for non-contiguous MFNs. */
2683 success = xen_exchange_memory(1, order, &in_frame, 1UL << order,
2686 /* 4. Map new pages in place of old pages. */
2688 xen_remap_exchanged_ptes(vstart, order, out_frames, 0);
2690 xen_remap_exchanged_ptes(vstart, order, NULL, in_frame);
2692 spin_unlock_irqrestore(&xen_reservation_lock, flags);
2694 EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
2696 #ifdef CONFIG_XEN_PVHVM
2697 #ifdef CONFIG_PROC_VMCORE
2699 * This function is used in two contexts:
2700 * - the kdump kernel has to check whether a pfn of the crashed kernel
2701 * was a ballooned page. vmcore is using this function to decide
2702 * whether to access a pfn of the crashed kernel.
2703 * - the kexec kernel has to check whether a pfn was ballooned by the
2704 * previous kernel. If the pfn is ballooned, handle it properly.
2705 * Returns 0 if the pfn is not backed by a RAM page, the caller may
2706 * handle the pfn special in this case.
2708 static int xen_oldmem_pfn_is_ram(unsigned long pfn)
2710 struct xen_hvm_get_mem_type a = {
2711 .domid = DOMID_SELF,
2716 if (HYPERVISOR_hvm_op(HVMOP_get_mem_type, &a))
2719 switch (a.mem_type) {
2720 case HVMMEM_mmio_dm:
2734 static void xen_hvm_exit_mmap(struct mm_struct *mm)
2736 struct xen_hvm_pagetable_dying a;
2739 a.domid = DOMID_SELF;
2740 a.gpa = __pa(mm->pgd);
2741 rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a);
2742 WARN_ON_ONCE(rc < 0);
2745 static int is_pagetable_dying_supported(void)
2747 struct xen_hvm_pagetable_dying a;
2750 a.domid = DOMID_SELF;
2752 rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a);
2754 printk(KERN_DEBUG "HVMOP_pagetable_dying not supported\n");
2760 void __init xen_hvm_init_mmu_ops(void)
2762 if (is_pagetable_dying_supported())
2763 pv_mmu_ops.exit_mmap = xen_hvm_exit_mmap;
2764 #ifdef CONFIG_PROC_VMCORE
2765 register_oldmem_pfn_is_ram(&xen_oldmem_pfn_is_ram);
2770 #define REMAP_BATCH_SIZE 16
2776 struct mmu_update *mmu_update;
2779 static int remap_area_mfn_pte_fn(pte_t *ptep, pgtable_t token,
2780 unsigned long addr, void *data)
2782 struct remap_data *rmd = data;
2783 pte_t pte = pte_mkspecial(mfn_pte(*rmd->mfn, rmd->prot));
2785 /* If we have a contiguous range, just update the mfn itself,
2786 else update pointer to be "next mfn". */
2787 if (rmd->contiguous)
2792 rmd->mmu_update->ptr = virt_to_machine(ptep).maddr;
2793 rmd->mmu_update->val = pte_val_ma(pte);
2799 static int do_remap_gfn(struct vm_area_struct *vma,
2801 xen_pfn_t *gfn, int nr,
2802 int *err_ptr, pgprot_t prot,
2804 struct page **pages)
2807 struct remap_data rmd;
2808 struct mmu_update mmu_update[REMAP_BATCH_SIZE];
2809 unsigned long range;
2812 BUG_ON(!((vma->vm_flags & (VM_PFNMAP | VM_IO)) == (VM_PFNMAP | VM_IO)));
2814 if (xen_feature(XENFEAT_auto_translated_physmap)) {
2815 #ifdef CONFIG_XEN_PVH
2816 /* We need to update the local page tables and the xen HAP */
2817 return xen_xlate_remap_gfn_array(vma, addr, gfn, nr, err_ptr,
2818 prot, domid, pages);
2826 /* We use the err_ptr to indicate if there we are doing a contiguous
2827 * mapping or a discontigious mapping. */
2828 rmd.contiguous = !err_ptr;
2833 int batch = min(REMAP_BATCH_SIZE, nr);
2834 int batch_left = batch;
2835 range = (unsigned long)batch << PAGE_SHIFT;
2837 rmd.mmu_update = mmu_update;
2838 err = apply_to_page_range(vma->vm_mm, addr, range,
2839 remap_area_mfn_pte_fn, &rmd);
2843 /* We record the error for each page that gives an error, but
2844 * continue mapping until the whole set is done */
2848 err = HYPERVISOR_mmu_update(&mmu_update[index],
2849 batch_left, &done, domid);
2852 * @err_ptr may be the same buffer as @gfn, so
2853 * only clear it after each chunk of @gfn is
2857 for (i = index; i < index + done; i++)
2864 done++; /* Skip failed frame. */
2869 } while (batch_left);
2879 xen_flush_tlb_all();
2881 return err < 0 ? err : mapped;
2884 int xen_remap_domain_gfn_range(struct vm_area_struct *vma,
2886 xen_pfn_t gfn, int nr,
2887 pgprot_t prot, unsigned domid,
2888 struct page **pages)
2890 return do_remap_gfn(vma, addr, &gfn, nr, NULL, prot, domid, pages);
2892 EXPORT_SYMBOL_GPL(xen_remap_domain_gfn_range);
2894 int xen_remap_domain_gfn_array(struct vm_area_struct *vma,
2896 xen_pfn_t *gfn, int nr,
2897 int *err_ptr, pgprot_t prot,
2898 unsigned domid, struct page **pages)
2900 /* We BUG_ON because it's a programmer error to pass a NULL err_ptr,
2901 * and the consequences later is quite hard to detect what the actual
2902 * cause of "wrong memory was mapped in".
2904 BUG_ON(err_ptr == NULL);
2905 return do_remap_gfn(vma, addr, gfn, nr, err_ptr, prot, domid, pages);
2907 EXPORT_SYMBOL_GPL(xen_remap_domain_gfn_array);
2910 /* Returns: 0 success */
2911 int xen_unmap_domain_gfn_range(struct vm_area_struct *vma,
2912 int numpgs, struct page **pages)
2914 if (!pages || !xen_feature(XENFEAT_auto_translated_physmap))
2917 #ifdef CONFIG_XEN_PVH
2918 return xen_xlate_unmap_gfn_range(vma, numpgs, pages);
2923 EXPORT_SYMBOL_GPL(xen_unmap_domain_gfn_range);