1 // SPDX-License-Identifier: GPL-2.0
6 * This file contains the various mmu fetch and update operations.
7 * The most important job they must perform is the mapping between the
8 * domain's pfn and the overall machine mfns.
10 * Xen allows guests to directly update the pagetable, in a controlled
11 * fashion. In other words, the guest modifies the same pagetable
12 * that the CPU actually uses, which eliminates the overhead of having
13 * a separate shadow pagetable.
15 * In order to allow this, it falls on the guest domain to map its
16 * notion of a "physical" pfn - which is just a domain-local linear
17 * address - into a real "machine address" which the CPU's MMU can
20 * A pgd_t/pmd_t/pte_t will typically contain an mfn, and so can be
21 * inserted directly into the pagetable. When creating a new
22 * pte/pmd/pgd, it converts the passed pfn into an mfn. Conversely,
23 * when reading the content back with __(pgd|pmd|pte)_val, it converts
24 * the mfn back into a pfn.
26 * The other constraint is that all pages which make up a pagetable
27 * must be mapped read-only in the guest. This prevents uncontrolled
28 * guest updates to the pagetable. Xen strictly enforces this, and
29 * will disallow any pagetable update which will end up mapping a
30 * pagetable page RW, and will disallow using any writable page as a
33 * Naively, when loading %cr3 with the base of a new pagetable, Xen
34 * would need to validate the whole pagetable before going on.
35 * Naturally, this is quite slow. The solution is to "pin" a
36 * pagetable, which enforces all the constraints on the pagetable even
37 * when it is not actively in use. This menas that Xen can be assured
38 * that it is still valid when you do load it into %cr3, and doesn't
39 * need to revalidate it.
41 * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
43 #include <linux/sched/mm.h>
44 #include <linux/debugfs.h>
45 #include <linux/bug.h>
46 #include <linux/vmalloc.h>
47 #include <linux/export.h>
48 #include <linux/init.h>
49 #include <linux/gfp.h>
50 #include <linux/memblock.h>
51 #include <linux/seq_file.h>
52 #include <linux/crash_dump.h>
53 #include <linux/pgtable.h>
54 #ifdef CONFIG_KEXEC_CORE
55 #include <linux/kexec.h>
58 #include <trace/events/xen.h>
60 #include <asm/tlbflush.h>
61 #include <asm/fixmap.h>
62 #include <asm/mmu_context.h>
63 #include <asm/setup.h>
64 #include <asm/paravirt.h>
65 #include <asm/e820/api.h>
66 #include <asm/linkage.h>
69 #include <asm/memtype.h>
73 #include <asm/xen/hypercall.h>
74 #include <asm/xen/hypervisor.h>
78 #include <xen/interface/xen.h>
79 #include <xen/interface/hvm/hvm_op.h>
80 #include <xen/interface/version.h>
81 #include <xen/interface/memory.h>
82 #include <xen/hvc-console.h>
84 #include "multicalls.h"
88 #ifdef CONFIG_X86_VSYSCALL_EMULATION
89 /* l3 pud for userspace vsyscall mapping */
90 static pud_t level3_user_vsyscall[PTRS_PER_PUD] __page_aligned_bss;
94 * Protects atomic reservation decrease/increase against concurrent increases.
95 * Also protects non-atomic updates of current_pages and balloon lists.
97 static DEFINE_SPINLOCK(xen_reservation_lock);
100 * Note about cr3 (pagetable base) values:
102 * xen_cr3 contains the current logical cr3 value; it contains the
103 * last set cr3. This may not be the current effective cr3, because
104 * its update may be being lazily deferred. However, a vcpu looking
105 * at its own cr3 can use this value knowing that it everything will
106 * be self-consistent.
108 * xen_current_cr3 contains the actual vcpu cr3; it is set once the
109 * hypercall to set the vcpu cr3 is complete (so it may be a little
110 * out of date, but it will never be set early). If one vcpu is
111 * looking at another vcpu's cr3 value, it should use this variable.
113 DEFINE_PER_CPU(unsigned long, xen_cr3); /* cr3 stored as physaddr */
114 DEFINE_PER_CPU(unsigned long, xen_current_cr3); /* actual vcpu cr3 */
116 static phys_addr_t xen_pt_base, xen_pt_size __initdata;
118 static DEFINE_STATIC_KEY_FALSE(xen_struct_pages_ready);
121 * Just beyond the highest usermode address. STACK_TOP_MAX has a
122 * redzone above it, so round it up to a PGD boundary.
124 #define USER_LIMIT ((STACK_TOP_MAX + PGDIR_SIZE - 1) & PGDIR_MASK)
126 void make_lowmem_page_readonly(void *vaddr)
129 unsigned long address = (unsigned long)vaddr;
132 pte = lookup_address(address, &level);
134 return; /* vaddr missing */
136 ptev = pte_wrprotect(*pte);
138 if (HYPERVISOR_update_va_mapping(address, ptev, 0))
142 void make_lowmem_page_readwrite(void *vaddr)
145 unsigned long address = (unsigned long)vaddr;
148 pte = lookup_address(address, &level);
150 return; /* vaddr missing */
152 ptev = pte_mkwrite(*pte);
154 if (HYPERVISOR_update_va_mapping(address, ptev, 0))
160 * During early boot all page table pages are pinned, but we do not have struct
161 * pages, so return true until struct pages are ready.
163 static bool xen_page_pinned(void *ptr)
165 if (static_branch_likely(&xen_struct_pages_ready)) {
166 struct page *page = virt_to_page(ptr);
168 return PagePinned(page);
173 static void xen_extend_mmu_update(const struct mmu_update *update)
175 struct multicall_space mcs;
176 struct mmu_update *u;
178 mcs = xen_mc_extend_args(__HYPERVISOR_mmu_update, sizeof(*u));
180 if (mcs.mc != NULL) {
183 mcs = __xen_mc_entry(sizeof(*u));
184 MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
191 static void xen_extend_mmuext_op(const struct mmuext_op *op)
193 struct multicall_space mcs;
196 mcs = xen_mc_extend_args(__HYPERVISOR_mmuext_op, sizeof(*u));
198 if (mcs.mc != NULL) {
201 mcs = __xen_mc_entry(sizeof(*u));
202 MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
209 static void xen_set_pmd_hyper(pmd_t *ptr, pmd_t val)
217 /* ptr may be ioremapped for 64-bit pagetable setup */
218 u.ptr = arbitrary_virt_to_machine(ptr).maddr;
219 u.val = pmd_val_ma(val);
220 xen_extend_mmu_update(&u);
222 xen_mc_issue(PARAVIRT_LAZY_MMU);
227 static void xen_set_pmd(pmd_t *ptr, pmd_t val)
229 trace_xen_mmu_set_pmd(ptr, val);
231 /* If page is not pinned, we can just update the entry
233 if (!xen_page_pinned(ptr)) {
238 xen_set_pmd_hyper(ptr, val);
242 * Associate a virtual page frame with a given physical page frame
243 * and protection flags for that frame.
245 void __init set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags)
247 if (HYPERVISOR_update_va_mapping(vaddr, mfn_pte(mfn, flags),
252 static bool xen_batched_set_pte(pte_t *ptep, pte_t pteval)
256 if (paravirt_get_lazy_mode() != PARAVIRT_LAZY_MMU)
261 u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE;
262 u.val = pte_val_ma(pteval);
263 xen_extend_mmu_update(&u);
265 xen_mc_issue(PARAVIRT_LAZY_MMU);
270 static inline void __xen_set_pte(pte_t *ptep, pte_t pteval)
272 if (!xen_batched_set_pte(ptep, pteval)) {
274 * Could call native_set_pte() here and trap and
275 * emulate the PTE write, but a hypercall is much cheaper.
279 u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE;
280 u.val = pte_val_ma(pteval);
281 HYPERVISOR_mmu_update(&u, 1, NULL, DOMID_SELF);
285 static void xen_set_pte(pte_t *ptep, pte_t pteval)
287 trace_xen_mmu_set_pte(ptep, pteval);
288 __xen_set_pte(ptep, pteval);
291 pte_t xen_ptep_modify_prot_start(struct vm_area_struct *vma,
292 unsigned long addr, pte_t *ptep)
294 /* Just return the pte as-is. We preserve the bits on commit */
295 trace_xen_mmu_ptep_modify_prot_start(vma->vm_mm, addr, ptep, *ptep);
299 void xen_ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr,
300 pte_t *ptep, pte_t pte)
304 trace_xen_mmu_ptep_modify_prot_commit(vma->vm_mm, addr, ptep, pte);
307 u.ptr = virt_to_machine(ptep).maddr | MMU_PT_UPDATE_PRESERVE_AD;
308 u.val = pte_val_ma(pte);
309 xen_extend_mmu_update(&u);
311 xen_mc_issue(PARAVIRT_LAZY_MMU);
314 /* Assume pteval_t is equivalent to all the other *val_t types. */
315 static pteval_t pte_mfn_to_pfn(pteval_t val)
317 if (val & _PAGE_PRESENT) {
318 unsigned long mfn = (val & XEN_PTE_MFN_MASK) >> PAGE_SHIFT;
319 unsigned long pfn = mfn_to_pfn(mfn);
321 pteval_t flags = val & PTE_FLAGS_MASK;
322 if (unlikely(pfn == ~0))
323 val = flags & ~_PAGE_PRESENT;
325 val = ((pteval_t)pfn << PAGE_SHIFT) | flags;
331 static pteval_t pte_pfn_to_mfn(pteval_t val)
333 if (val & _PAGE_PRESENT) {
334 unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
335 pteval_t flags = val & PTE_FLAGS_MASK;
338 mfn = __pfn_to_mfn(pfn);
341 * If there's no mfn for the pfn, then just create an
342 * empty non-present pte. Unfortunately this loses
343 * information about the original pfn, so
344 * pte_mfn_to_pfn is asymmetric.
346 if (unlikely(mfn == INVALID_P2M_ENTRY)) {
350 mfn &= ~(FOREIGN_FRAME_BIT | IDENTITY_FRAME_BIT);
351 val = ((pteval_t)mfn << PAGE_SHIFT) | flags;
357 __visible pteval_t xen_pte_val(pte_t pte)
359 pteval_t pteval = pte.pte;
361 return pte_mfn_to_pfn(pteval);
363 PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val);
365 __visible pgdval_t xen_pgd_val(pgd_t pgd)
367 return pte_mfn_to_pfn(pgd.pgd);
369 PV_CALLEE_SAVE_REGS_THUNK(xen_pgd_val);
371 __visible pte_t xen_make_pte(pteval_t pte)
373 pte = pte_pfn_to_mfn(pte);
375 return native_make_pte(pte);
377 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte);
379 __visible pgd_t xen_make_pgd(pgdval_t pgd)
381 pgd = pte_pfn_to_mfn(pgd);
382 return native_make_pgd(pgd);
384 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pgd);
386 __visible pmdval_t xen_pmd_val(pmd_t pmd)
388 return pte_mfn_to_pfn(pmd.pmd);
390 PV_CALLEE_SAVE_REGS_THUNK(xen_pmd_val);
392 static void xen_set_pud_hyper(pud_t *ptr, pud_t val)
400 /* ptr may be ioremapped for 64-bit pagetable setup */
401 u.ptr = arbitrary_virt_to_machine(ptr).maddr;
402 u.val = pud_val_ma(val);
403 xen_extend_mmu_update(&u);
405 xen_mc_issue(PARAVIRT_LAZY_MMU);
410 static void xen_set_pud(pud_t *ptr, pud_t val)
412 trace_xen_mmu_set_pud(ptr, val);
414 /* If page is not pinned, we can just update the entry
416 if (!xen_page_pinned(ptr)) {
421 xen_set_pud_hyper(ptr, val);
424 __visible pmd_t xen_make_pmd(pmdval_t pmd)
426 pmd = pte_pfn_to_mfn(pmd);
427 return native_make_pmd(pmd);
429 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pmd);
431 __visible pudval_t xen_pud_val(pud_t pud)
433 return pte_mfn_to_pfn(pud.pud);
435 PV_CALLEE_SAVE_REGS_THUNK(xen_pud_val);
437 __visible pud_t xen_make_pud(pudval_t pud)
439 pud = pte_pfn_to_mfn(pud);
441 return native_make_pud(pud);
443 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pud);
445 static pgd_t *xen_get_user_pgd(pgd_t *pgd)
447 pgd_t *pgd_page = (pgd_t *)(((unsigned long)pgd) & PAGE_MASK);
448 unsigned offset = pgd - pgd_page;
449 pgd_t *user_ptr = NULL;
451 if (offset < pgd_index(USER_LIMIT)) {
452 struct page *page = virt_to_page(pgd_page);
453 user_ptr = (pgd_t *)page->private;
461 static void __xen_set_p4d_hyper(p4d_t *ptr, p4d_t val)
465 u.ptr = virt_to_machine(ptr).maddr;
466 u.val = p4d_val_ma(val);
467 xen_extend_mmu_update(&u);
471 * Raw hypercall-based set_p4d, intended for in early boot before
472 * there's a page structure. This implies:
473 * 1. The only existing pagetable is the kernel's
474 * 2. It is always pinned
475 * 3. It has no user pagetable attached to it
477 static void __init xen_set_p4d_hyper(p4d_t *ptr, p4d_t val)
483 __xen_set_p4d_hyper(ptr, val);
485 xen_mc_issue(PARAVIRT_LAZY_MMU);
490 static void xen_set_p4d(p4d_t *ptr, p4d_t val)
492 pgd_t *user_ptr = xen_get_user_pgd((pgd_t *)ptr);
495 trace_xen_mmu_set_p4d(ptr, (p4d_t *)user_ptr, val);
497 /* If page is not pinned, we can just update the entry
499 if (!xen_page_pinned(ptr)) {
502 WARN_ON(xen_page_pinned(user_ptr));
503 pgd_val.pgd = p4d_val_ma(val);
509 /* If it's pinned, then we can at least batch the kernel and
510 user updates together. */
513 __xen_set_p4d_hyper(ptr, val);
515 __xen_set_p4d_hyper((p4d_t *)user_ptr, val);
517 xen_mc_issue(PARAVIRT_LAZY_MMU);
520 #if CONFIG_PGTABLE_LEVELS >= 5
521 __visible p4dval_t xen_p4d_val(p4d_t p4d)
523 return pte_mfn_to_pfn(p4d.p4d);
525 PV_CALLEE_SAVE_REGS_THUNK(xen_p4d_val);
527 __visible p4d_t xen_make_p4d(p4dval_t p4d)
529 p4d = pte_pfn_to_mfn(p4d);
531 return native_make_p4d(p4d);
533 PV_CALLEE_SAVE_REGS_THUNK(xen_make_p4d);
534 #endif /* CONFIG_PGTABLE_LEVELS >= 5 */
536 static void xen_pmd_walk(struct mm_struct *mm, pmd_t *pmd,
537 void (*func)(struct mm_struct *mm, struct page *,
539 bool last, unsigned long limit)
543 nr = last ? pmd_index(limit) + 1 : PTRS_PER_PMD;
544 for (i = 0; i < nr; i++) {
545 if (!pmd_none(pmd[i]))
546 (*func)(mm, pmd_page(pmd[i]), PT_PTE);
550 static void xen_pud_walk(struct mm_struct *mm, pud_t *pud,
551 void (*func)(struct mm_struct *mm, struct page *,
553 bool last, unsigned long limit)
557 nr = last ? pud_index(limit) + 1 : PTRS_PER_PUD;
558 for (i = 0; i < nr; i++) {
561 if (pud_none(pud[i]))
564 pmd = pmd_offset(&pud[i], 0);
565 if (PTRS_PER_PMD > 1)
566 (*func)(mm, virt_to_page(pmd), PT_PMD);
567 xen_pmd_walk(mm, pmd, func, last && i == nr - 1, limit);
571 static void xen_p4d_walk(struct mm_struct *mm, p4d_t *p4d,
572 void (*func)(struct mm_struct *mm, struct page *,
574 bool last, unsigned long limit)
582 pud = pud_offset(p4d, 0);
583 if (PTRS_PER_PUD > 1)
584 (*func)(mm, virt_to_page(pud), PT_PUD);
585 xen_pud_walk(mm, pud, func, last, limit);
589 * (Yet another) pagetable walker. This one is intended for pinning a
590 * pagetable. This means that it walks a pagetable and calls the
591 * callback function on each page it finds making up the page table,
592 * at every level. It walks the entire pagetable, but it only bothers
593 * pinning pte pages which are below limit. In the normal case this
594 * will be STACK_TOP_MAX, but at boot we need to pin up to
597 * We must skip the Xen hole in the middle of the address space, just after
598 * the big x86-64 virtual hole.
600 static void __xen_pgd_walk(struct mm_struct *mm, pgd_t *pgd,
601 void (*func)(struct mm_struct *mm, struct page *,
606 unsigned hole_low = 0, hole_high = 0;
608 /* The limit is the last byte to be touched */
610 BUG_ON(limit >= FIXADDR_TOP);
613 * 64-bit has a great big hole in the middle of the address
614 * space, which contains the Xen mappings.
616 hole_low = pgd_index(GUARD_HOLE_BASE_ADDR);
617 hole_high = pgd_index(GUARD_HOLE_END_ADDR);
619 nr = pgd_index(limit) + 1;
620 for (i = 0; i < nr; i++) {
623 if (i >= hole_low && i < hole_high)
626 if (pgd_none(pgd[i]))
629 p4d = p4d_offset(&pgd[i], 0);
630 xen_p4d_walk(mm, p4d, func, i == nr - 1, limit);
633 /* Do the top level last, so that the callbacks can use it as
634 a cue to do final things like tlb flushes. */
635 (*func)(mm, virt_to_page(pgd), PT_PGD);
638 static void xen_pgd_walk(struct mm_struct *mm,
639 void (*func)(struct mm_struct *mm, struct page *,
643 __xen_pgd_walk(mm, mm->pgd, func, limit);
646 /* If we're using split pte locks, then take the page's lock and
647 return a pointer to it. Otherwise return NULL. */
648 static spinlock_t *xen_pte_lock(struct page *page, struct mm_struct *mm)
650 spinlock_t *ptl = NULL;
652 #if USE_SPLIT_PTE_PTLOCKS
653 ptl = ptlock_ptr(page);
654 spin_lock_nest_lock(ptl, &mm->page_table_lock);
660 static void xen_pte_unlock(void *v)
666 static void xen_do_pin(unsigned level, unsigned long pfn)
671 op.arg1.mfn = pfn_to_mfn(pfn);
673 xen_extend_mmuext_op(&op);
676 static void xen_pin_page(struct mm_struct *mm, struct page *page,
679 unsigned pgfl = TestSetPagePinned(page);
682 void *pt = lowmem_page_address(page);
683 unsigned long pfn = page_to_pfn(page);
684 struct multicall_space mcs = __xen_mc_entry(0);
688 * We need to hold the pagetable lock between the time
689 * we make the pagetable RO and when we actually pin
690 * it. If we don't, then other users may come in and
691 * attempt to update the pagetable by writing it,
692 * which will fail because the memory is RO but not
693 * pinned, so Xen won't do the trap'n'emulate.
695 * If we're using split pte locks, we can't hold the
696 * entire pagetable's worth of locks during the
697 * traverse, because we may wrap the preempt count (8
698 * bits). The solution is to mark RO and pin each PTE
699 * page while holding the lock. This means the number
700 * of locks we end up holding is never more than a
701 * batch size (~32 entries, at present).
703 * If we're not using split pte locks, we needn't pin
704 * the PTE pages independently, because we're
705 * protected by the overall pagetable lock.
709 ptl = xen_pte_lock(page, mm);
711 MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
712 pfn_pte(pfn, PAGE_KERNEL_RO),
713 level == PT_PGD ? UVMF_TLB_FLUSH : 0);
716 xen_do_pin(MMUEXT_PIN_L1_TABLE, pfn);
718 /* Queue a deferred unlock for when this batch
720 xen_mc_callback(xen_pte_unlock, ptl);
725 /* This is called just after a mm has been created, but it has not
726 been used yet. We need to make sure that its pagetable is all
727 read-only, and can be pinned. */
728 static void __xen_pgd_pin(struct mm_struct *mm, pgd_t *pgd)
730 pgd_t *user_pgd = xen_get_user_pgd(pgd);
732 trace_xen_mmu_pgd_pin(mm, pgd);
736 __xen_pgd_walk(mm, pgd, xen_pin_page, USER_LIMIT);
738 xen_do_pin(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(pgd)));
741 xen_pin_page(mm, virt_to_page(user_pgd), PT_PGD);
742 xen_do_pin(MMUEXT_PIN_L4_TABLE,
743 PFN_DOWN(__pa(user_pgd)));
749 static void xen_pgd_pin(struct mm_struct *mm)
751 __xen_pgd_pin(mm, mm->pgd);
755 * On save, we need to pin all pagetables to make sure they get their
756 * mfns turned into pfns. Search the list for any unpinned pgds and pin
757 * them (unpinned pgds are not currently in use, probably because the
758 * process is under construction or destruction).
760 * Expected to be called in stop_machine() ("equivalent to taking
761 * every spinlock in the system"), so the locking doesn't really
762 * matter all that much.
764 void xen_mm_pin_all(void)
768 spin_lock(&pgd_lock);
770 list_for_each_entry(page, &pgd_list, lru) {
771 if (!PagePinned(page)) {
772 __xen_pgd_pin(&init_mm, (pgd_t *)page_address(page));
773 SetPageSavePinned(page);
777 spin_unlock(&pgd_lock);
780 static void __init xen_mark_pinned(struct mm_struct *mm, struct page *page,
787 * The init_mm pagetable is really pinned as soon as its created, but
788 * that's before we have page structures to store the bits. So do all
789 * the book-keeping now once struct pages for allocated pages are
790 * initialized. This happens only after memblock_free_all() is called.
792 static void __init xen_after_bootmem(void)
794 static_branch_enable(&xen_struct_pages_ready);
795 #ifdef CONFIG_X86_VSYSCALL_EMULATION
796 SetPagePinned(virt_to_page(level3_user_vsyscall));
798 xen_pgd_walk(&init_mm, xen_mark_pinned, FIXADDR_TOP);
801 static void xen_unpin_page(struct mm_struct *mm, struct page *page,
804 unsigned pgfl = TestClearPagePinned(page);
807 void *pt = lowmem_page_address(page);
808 unsigned long pfn = page_to_pfn(page);
809 spinlock_t *ptl = NULL;
810 struct multicall_space mcs;
813 * Do the converse to pin_page. If we're using split
814 * pte locks, we must be holding the lock for while
815 * the pte page is unpinned but still RO to prevent
816 * concurrent updates from seeing it in this
817 * partially-pinned state.
819 if (level == PT_PTE) {
820 ptl = xen_pte_lock(page, mm);
823 xen_do_pin(MMUEXT_UNPIN_TABLE, pfn);
826 mcs = __xen_mc_entry(0);
828 MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
829 pfn_pte(pfn, PAGE_KERNEL),
830 level == PT_PGD ? UVMF_TLB_FLUSH : 0);
833 /* unlock when batch completed */
834 xen_mc_callback(xen_pte_unlock, ptl);
839 /* Release a pagetables pages back as normal RW */
840 static void __xen_pgd_unpin(struct mm_struct *mm, pgd_t *pgd)
842 pgd_t *user_pgd = xen_get_user_pgd(pgd);
844 trace_xen_mmu_pgd_unpin(mm, pgd);
848 xen_do_pin(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
851 xen_do_pin(MMUEXT_UNPIN_TABLE,
852 PFN_DOWN(__pa(user_pgd)));
853 xen_unpin_page(mm, virt_to_page(user_pgd), PT_PGD);
856 __xen_pgd_walk(mm, pgd, xen_unpin_page, USER_LIMIT);
861 static void xen_pgd_unpin(struct mm_struct *mm)
863 __xen_pgd_unpin(mm, mm->pgd);
867 * On resume, undo any pinning done at save, so that the rest of the
868 * kernel doesn't see any unexpected pinned pagetables.
870 void xen_mm_unpin_all(void)
874 spin_lock(&pgd_lock);
876 list_for_each_entry(page, &pgd_list, lru) {
877 if (PageSavePinned(page)) {
878 BUG_ON(!PagePinned(page));
879 __xen_pgd_unpin(&init_mm, (pgd_t *)page_address(page));
880 ClearPageSavePinned(page);
884 spin_unlock(&pgd_lock);
887 static void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
889 spin_lock(&next->page_table_lock);
891 spin_unlock(&next->page_table_lock);
894 static void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
896 spin_lock(&mm->page_table_lock);
898 spin_unlock(&mm->page_table_lock);
901 static void drop_mm_ref_this_cpu(void *info)
903 struct mm_struct *mm = info;
905 if (this_cpu_read(cpu_tlbstate.loaded_mm) == mm)
906 leave_mm(smp_processor_id());
909 * If this cpu still has a stale cr3 reference, then make sure
910 * it has been flushed.
912 if (this_cpu_read(xen_current_cr3) == __pa(mm->pgd))
918 * Another cpu may still have their %cr3 pointing at the pagetable, so
919 * we need to repoint it somewhere else before we can unpin it.
921 static void xen_drop_mm_ref(struct mm_struct *mm)
926 drop_mm_ref_this_cpu(mm);
928 /* Get the "official" set of cpus referring to our pagetable. */
929 if (!alloc_cpumask_var(&mask, GFP_ATOMIC)) {
930 for_each_online_cpu(cpu) {
931 if (per_cpu(xen_current_cr3, cpu) != __pa(mm->pgd))
933 smp_call_function_single(cpu, drop_mm_ref_this_cpu, mm, 1);
939 * It's possible that a vcpu may have a stale reference to our
940 * cr3, because its in lazy mode, and it hasn't yet flushed
941 * its set of pending hypercalls yet. In this case, we can
942 * look at its actual current cr3 value, and force it to flush
946 for_each_online_cpu(cpu) {
947 if (per_cpu(xen_current_cr3, cpu) == __pa(mm->pgd))
948 cpumask_set_cpu(cpu, mask);
951 smp_call_function_many(mask, drop_mm_ref_this_cpu, mm, 1);
952 free_cpumask_var(mask);
955 static void xen_drop_mm_ref(struct mm_struct *mm)
957 drop_mm_ref_this_cpu(mm);
962 * While a process runs, Xen pins its pagetables, which means that the
963 * hypervisor forces it to be read-only, and it controls all updates
964 * to it. This means that all pagetable updates have to go via the
965 * hypervisor, which is moderately expensive.
967 * Since we're pulling the pagetable down, we switch to use init_mm,
968 * unpin old process pagetable and mark it all read-write, which
969 * allows further operations on it to be simple memory accesses.
971 * The only subtle point is that another CPU may be still using the
972 * pagetable because of lazy tlb flushing. This means we need need to
973 * switch all CPUs off this pagetable before we can unpin it.
975 static void xen_exit_mmap(struct mm_struct *mm)
977 get_cpu(); /* make sure we don't move around */
981 spin_lock(&mm->page_table_lock);
983 /* pgd may not be pinned in the error exit path of execve */
984 if (xen_page_pinned(mm->pgd))
987 spin_unlock(&mm->page_table_lock);
990 static void xen_post_allocator_init(void);
992 static void __init pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
997 op.arg1.mfn = pfn_to_mfn(pfn);
998 if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
1002 static void __init xen_cleanhighmap(unsigned long vaddr,
1003 unsigned long vaddr_end)
1005 unsigned long kernel_end = roundup((unsigned long)_brk_end, PMD_SIZE) - 1;
1006 pmd_t *pmd = level2_kernel_pgt + pmd_index(vaddr);
1008 /* NOTE: The loop is more greedy than the cleanup_highmap variant.
1009 * We include the PMD passed in on _both_ boundaries. */
1010 for (; vaddr <= vaddr_end && (pmd < (level2_kernel_pgt + PTRS_PER_PMD));
1011 pmd++, vaddr += PMD_SIZE) {
1014 if (vaddr < (unsigned long) _text || vaddr > kernel_end)
1015 set_pmd(pmd, __pmd(0));
1017 /* In case we did something silly, we should crash in this function
1018 * instead of somewhere later and be confusing. */
1023 * Make a page range writeable and free it.
1025 static void __init xen_free_ro_pages(unsigned long paddr, unsigned long size)
1027 void *vaddr = __va(paddr);
1028 void *vaddr_end = vaddr + size;
1030 for (; vaddr < vaddr_end; vaddr += PAGE_SIZE)
1031 make_lowmem_page_readwrite(vaddr);
1033 memblock_phys_free(paddr, size);
1036 static void __init xen_cleanmfnmap_free_pgtbl(void *pgtbl, bool unpin)
1038 unsigned long pa = __pa(pgtbl) & PHYSICAL_PAGE_MASK;
1041 pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(pa));
1042 ClearPagePinned(virt_to_page(__va(pa)));
1043 xen_free_ro_pages(pa, PAGE_SIZE);
1046 static void __init xen_cleanmfnmap_pmd(pmd_t *pmd, bool unpin)
1052 if (pmd_large(*pmd)) {
1053 pa = pmd_val(*pmd) & PHYSICAL_PAGE_MASK;
1054 xen_free_ro_pages(pa, PMD_SIZE);
1058 pte_tbl = pte_offset_kernel(pmd, 0);
1059 for (i = 0; i < PTRS_PER_PTE; i++) {
1060 if (pte_none(pte_tbl[i]))
1062 pa = pte_pfn(pte_tbl[i]) << PAGE_SHIFT;
1063 xen_free_ro_pages(pa, PAGE_SIZE);
1065 set_pmd(pmd, __pmd(0));
1066 xen_cleanmfnmap_free_pgtbl(pte_tbl, unpin);
1069 static void __init xen_cleanmfnmap_pud(pud_t *pud, bool unpin)
1075 if (pud_large(*pud)) {
1076 pa = pud_val(*pud) & PHYSICAL_PAGE_MASK;
1077 xen_free_ro_pages(pa, PUD_SIZE);
1081 pmd_tbl = pmd_offset(pud, 0);
1082 for (i = 0; i < PTRS_PER_PMD; i++) {
1083 if (pmd_none(pmd_tbl[i]))
1085 xen_cleanmfnmap_pmd(pmd_tbl + i, unpin);
1087 set_pud(pud, __pud(0));
1088 xen_cleanmfnmap_free_pgtbl(pmd_tbl, unpin);
1091 static void __init xen_cleanmfnmap_p4d(p4d_t *p4d, bool unpin)
1097 if (p4d_large(*p4d)) {
1098 pa = p4d_val(*p4d) & PHYSICAL_PAGE_MASK;
1099 xen_free_ro_pages(pa, P4D_SIZE);
1103 pud_tbl = pud_offset(p4d, 0);
1104 for (i = 0; i < PTRS_PER_PUD; i++) {
1105 if (pud_none(pud_tbl[i]))
1107 xen_cleanmfnmap_pud(pud_tbl + i, unpin);
1109 set_p4d(p4d, __p4d(0));
1110 xen_cleanmfnmap_free_pgtbl(pud_tbl, unpin);
1114 * Since it is well isolated we can (and since it is perhaps large we should)
1115 * also free the page tables mapping the initial P->M table.
1117 static void __init xen_cleanmfnmap(unsigned long vaddr)
1123 unpin = (vaddr == 2 * PGDIR_SIZE);
1125 pgd = pgd_offset_k(vaddr);
1126 p4d = p4d_offset(pgd, 0);
1127 if (!p4d_none(*p4d))
1128 xen_cleanmfnmap_p4d(p4d, unpin);
1131 static void __init xen_pagetable_p2m_free(void)
1136 size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
1138 /* No memory or already called. */
1139 if ((unsigned long)xen_p2m_addr == xen_start_info->mfn_list)
1142 /* using __ka address and sticking INVALID_P2M_ENTRY! */
1143 memset((void *)xen_start_info->mfn_list, 0xff, size);
1145 addr = xen_start_info->mfn_list;
1147 * We could be in __ka space.
1148 * We roundup to the PMD, which means that if anybody at this stage is
1149 * using the __ka address of xen_start_info or
1150 * xen_start_info->shared_info they are in going to crash. Fortunately
1151 * we have already revectored in xen_setup_kernel_pagetable.
1153 size = roundup(size, PMD_SIZE);
1155 if (addr >= __START_KERNEL_map) {
1156 xen_cleanhighmap(addr, addr + size);
1157 size = PAGE_ALIGN(xen_start_info->nr_pages *
1158 sizeof(unsigned long));
1159 memblock_free((void *)addr, size);
1161 xen_cleanmfnmap(addr);
1165 static void __init xen_pagetable_cleanhighmap(void)
1170 /* At this stage, cleanup_highmap has already cleaned __ka space
1171 * from _brk_limit way up to the max_pfn_mapped (which is the end of
1172 * the ramdisk). We continue on, erasing PMD entries that point to page
1173 * tables - do note that they are accessible at this stage via __va.
1174 * As Xen is aligning the memory end to a 4MB boundary, for good
1175 * measure we also round up to PMD_SIZE * 2 - which means that if
1176 * anybody is using __ka address to the initial boot-stack - and try
1177 * to use it - they are going to crash. The xen_start_info has been
1178 * taken care of already in xen_setup_kernel_pagetable. */
1179 addr = xen_start_info->pt_base;
1180 size = xen_start_info->nr_pt_frames * PAGE_SIZE;
1182 xen_cleanhighmap(addr, roundup(addr + size, PMD_SIZE * 2));
1183 xen_start_info->pt_base = (unsigned long)__va(__pa(xen_start_info->pt_base));
1186 static void __init xen_pagetable_p2m_setup(void)
1188 xen_vmalloc_p2m_tree();
1190 xen_pagetable_p2m_free();
1192 xen_pagetable_cleanhighmap();
1194 /* And revector! Bye bye old array */
1195 xen_start_info->mfn_list = (unsigned long)xen_p2m_addr;
1198 static void __init xen_pagetable_init(void)
1201 * The majority of further PTE writes is to pagetables already
1202 * announced as such to Xen. Hence it is more efficient to use
1203 * hypercalls for these updates.
1205 pv_ops.mmu.set_pte = __xen_set_pte;
1208 xen_post_allocator_init();
1210 xen_pagetable_p2m_setup();
1212 /* Allocate and initialize top and mid mfn levels for p2m structure */
1213 xen_build_mfn_list_list();
1215 /* Remap memory freed due to conflicts with E820 map */
1217 xen_setup_mfn_list_list();
1220 static noinstr void xen_write_cr2(unsigned long cr2)
1222 this_cpu_read(xen_vcpu)->arch.cr2 = cr2;
1225 static noinline void xen_flush_tlb(void)
1227 struct mmuext_op *op;
1228 struct multicall_space mcs;
1232 mcs = xen_mc_entry(sizeof(*op));
1235 op->cmd = MMUEXT_TLB_FLUSH_LOCAL;
1236 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
1238 xen_mc_issue(PARAVIRT_LAZY_MMU);
1243 static void xen_flush_tlb_one_user(unsigned long addr)
1245 struct mmuext_op *op;
1246 struct multicall_space mcs;
1248 trace_xen_mmu_flush_tlb_one_user(addr);
1252 mcs = xen_mc_entry(sizeof(*op));
1254 op->cmd = MMUEXT_INVLPG_LOCAL;
1255 op->arg1.linear_addr = addr & PAGE_MASK;
1256 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
1258 xen_mc_issue(PARAVIRT_LAZY_MMU);
1263 static void xen_flush_tlb_multi(const struct cpumask *cpus,
1264 const struct flush_tlb_info *info)
1267 struct mmuext_op op;
1268 DECLARE_BITMAP(mask, NR_CPUS);
1270 struct multicall_space mcs;
1271 const size_t mc_entry_size = sizeof(args->op) +
1272 sizeof(args->mask[0]) * BITS_TO_LONGS(num_possible_cpus());
1274 trace_xen_mmu_flush_tlb_multi(cpus, info->mm, info->start, info->end);
1276 if (cpumask_empty(cpus))
1277 return; /* nothing to do */
1279 mcs = xen_mc_entry(mc_entry_size);
1281 args->op.arg2.vcpumask = to_cpumask(args->mask);
1283 /* Remove any offline CPUs */
1284 cpumask_and(to_cpumask(args->mask), cpus, cpu_online_mask);
1286 args->op.cmd = MMUEXT_TLB_FLUSH_MULTI;
1287 if (info->end != TLB_FLUSH_ALL &&
1288 (info->end - info->start) <= PAGE_SIZE) {
1289 args->op.cmd = MMUEXT_INVLPG_MULTI;
1290 args->op.arg1.linear_addr = info->start;
1293 MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF);
1295 xen_mc_issue(PARAVIRT_LAZY_MMU);
1298 static unsigned long xen_read_cr3(void)
1300 return this_cpu_read(xen_cr3);
1303 static void set_current_cr3(void *v)
1305 this_cpu_write(xen_current_cr3, (unsigned long)v);
1308 static void __xen_write_cr3(bool kernel, unsigned long cr3)
1310 struct mmuext_op op;
1313 trace_xen_mmu_write_cr3(kernel, cr3);
1316 mfn = pfn_to_mfn(PFN_DOWN(cr3));
1320 WARN_ON(mfn == 0 && kernel);
1322 op.cmd = kernel ? MMUEXT_NEW_BASEPTR : MMUEXT_NEW_USER_BASEPTR;
1325 xen_extend_mmuext_op(&op);
1328 this_cpu_write(xen_cr3, cr3);
1330 /* Update xen_current_cr3 once the batch has actually
1332 xen_mc_callback(set_current_cr3, (void *)cr3);
1335 static void xen_write_cr3(unsigned long cr3)
1337 pgd_t *user_pgd = xen_get_user_pgd(__va(cr3));
1339 BUG_ON(preemptible());
1341 xen_mc_batch(); /* disables interrupts */
1343 /* Update while interrupts are disabled, so its atomic with
1345 this_cpu_write(xen_cr3, cr3);
1347 __xen_write_cr3(true, cr3);
1350 __xen_write_cr3(false, __pa(user_pgd));
1352 __xen_write_cr3(false, 0);
1354 xen_mc_issue(PARAVIRT_LAZY_CPU); /* interrupts restored */
1358 * At the start of the day - when Xen launches a guest, it has already
1359 * built pagetables for the guest. We diligently look over them
1360 * in xen_setup_kernel_pagetable and graft as appropriate them in the
1361 * init_top_pgt and its friends. Then when we are happy we load
1362 * the new init_top_pgt - and continue on.
1364 * The generic code starts (start_kernel) and 'init_mem_mapping' sets
1365 * up the rest of the pagetables. When it has completed it loads the cr3.
1366 * N.B. that baremetal would start at 'start_kernel' (and the early
1367 * #PF handler would create bootstrap pagetables) - so we are running
1368 * with the same assumptions as what to do when write_cr3 is executed
1371 * Since there are no user-page tables at all, we have two variants
1372 * of xen_write_cr3 - the early bootup (this one), and the late one
1373 * (xen_write_cr3). The reason we have to do that is that in 64-bit
1374 * the Linux kernel and user-space are both in ring 3 while the
1375 * hypervisor is in ring 0.
1377 static void __init xen_write_cr3_init(unsigned long cr3)
1379 BUG_ON(preemptible());
1381 xen_mc_batch(); /* disables interrupts */
1383 /* Update while interrupts are disabled, so its atomic with
1385 this_cpu_write(xen_cr3, cr3);
1387 __xen_write_cr3(true, cr3);
1389 xen_mc_issue(PARAVIRT_LAZY_CPU); /* interrupts restored */
1392 static int xen_pgd_alloc(struct mm_struct *mm)
1394 pgd_t *pgd = mm->pgd;
1395 struct page *page = virt_to_page(pgd);
1399 BUG_ON(PagePinned(virt_to_page(pgd)));
1400 BUG_ON(page->private != 0);
1402 user_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
1403 page->private = (unsigned long)user_pgd;
1405 if (user_pgd != NULL) {
1406 #ifdef CONFIG_X86_VSYSCALL_EMULATION
1407 user_pgd[pgd_index(VSYSCALL_ADDR)] =
1408 __pgd(__pa(level3_user_vsyscall) | _PAGE_TABLE);
1413 BUG_ON(PagePinned(virt_to_page(xen_get_user_pgd(pgd))));
1418 static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
1420 pgd_t *user_pgd = xen_get_user_pgd(pgd);
1423 free_page((unsigned long)user_pgd);
1427 * Init-time set_pte while constructing initial pagetables, which
1428 * doesn't allow RO page table pages to be remapped RW.
1430 * If there is no MFN for this PFN then this page is initially
1431 * ballooned out so clear the PTE (as in decrease_reservation() in
1432 * drivers/xen/balloon.c).
1434 * Many of these PTE updates are done on unpinned and writable pages
1435 * and doing a hypercall for these is unnecessary and expensive. At
1436 * this point it is rarely possible to tell if a page is pinned, so
1437 * mostly write the PTE directly and rely on Xen trapping and
1438 * emulating any updates as necessary.
1440 static void __init xen_set_pte_init(pte_t *ptep, pte_t pte)
1442 if (unlikely(is_early_ioremap_ptep(ptep)))
1443 __xen_set_pte(ptep, pte);
1445 native_set_pte(ptep, pte);
1448 __visible pte_t xen_make_pte_init(pteval_t pte)
1453 * Pages belonging to the initial p2m list mapped outside the default
1454 * address range must be mapped read-only. This region contains the
1455 * page tables for mapping the p2m list, too, and page tables MUST be
1458 pfn = (pte & PTE_PFN_MASK) >> PAGE_SHIFT;
1459 if (xen_start_info->mfn_list < __START_KERNEL_map &&
1460 pfn >= xen_start_info->first_p2m_pfn &&
1461 pfn < xen_start_info->first_p2m_pfn + xen_start_info->nr_p2m_frames)
1464 pte = pte_pfn_to_mfn(pte);
1465 return native_make_pte(pte);
1467 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte_init);
1469 /* Early in boot, while setting up the initial pagetable, assume
1470 everything is pinned. */
1471 static void __init xen_alloc_pte_init(struct mm_struct *mm, unsigned long pfn)
1473 #ifdef CONFIG_FLATMEM
1474 BUG_ON(mem_map); /* should only be used early */
1476 make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
1477 pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
1480 /* Used for pmd and pud */
1481 static void __init xen_alloc_pmd_init(struct mm_struct *mm, unsigned long pfn)
1483 #ifdef CONFIG_FLATMEM
1484 BUG_ON(mem_map); /* should only be used early */
1486 make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
1489 /* Early release_pte assumes that all pts are pinned, since there's
1490 only init_mm and anything attached to that is pinned. */
1491 static void __init xen_release_pte_init(unsigned long pfn)
1493 pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
1494 make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
1497 static void __init xen_release_pmd_init(unsigned long pfn)
1499 make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
1502 static inline void __pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
1504 struct multicall_space mcs;
1505 struct mmuext_op *op;
1507 mcs = __xen_mc_entry(sizeof(*op));
1510 op->arg1.mfn = pfn_to_mfn(pfn);
1512 MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
1515 static inline void __set_pfn_prot(unsigned long pfn, pgprot_t prot)
1517 struct multicall_space mcs;
1518 unsigned long addr = (unsigned long)__va(pfn << PAGE_SHIFT);
1520 mcs = __xen_mc_entry(0);
1521 MULTI_update_va_mapping(mcs.mc, (unsigned long)addr,
1522 pfn_pte(pfn, prot), 0);
1525 /* This needs to make sure the new pte page is pinned iff its being
1526 attached to a pinned pagetable. */
1527 static inline void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn,
1530 bool pinned = xen_page_pinned(mm->pgd);
1532 trace_xen_mmu_alloc_ptpage(mm, pfn, level, pinned);
1535 struct page *page = pfn_to_page(pfn);
1538 if (static_branch_likely(&xen_struct_pages_ready)) {
1539 pinned = PagePinned(page);
1540 SetPagePinned(page);
1545 __set_pfn_prot(pfn, PAGE_KERNEL_RO);
1547 if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS && !pinned)
1548 __pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
1550 xen_mc_issue(PARAVIRT_LAZY_MMU);
1554 static void xen_alloc_pte(struct mm_struct *mm, unsigned long pfn)
1556 xen_alloc_ptpage(mm, pfn, PT_PTE);
1559 static void xen_alloc_pmd(struct mm_struct *mm, unsigned long pfn)
1561 xen_alloc_ptpage(mm, pfn, PT_PMD);
1564 /* This should never happen until we're OK to use struct page */
1565 static inline void xen_release_ptpage(unsigned long pfn, unsigned level)
1567 struct page *page = pfn_to_page(pfn);
1568 bool pinned = PagePinned(page);
1570 trace_xen_mmu_release_ptpage(pfn, level, pinned);
1575 if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS)
1576 __pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
1578 __set_pfn_prot(pfn, PAGE_KERNEL);
1580 xen_mc_issue(PARAVIRT_LAZY_MMU);
1582 ClearPagePinned(page);
1586 static void xen_release_pte(unsigned long pfn)
1588 xen_release_ptpage(pfn, PT_PTE);
1591 static void xen_release_pmd(unsigned long pfn)
1593 xen_release_ptpage(pfn, PT_PMD);
1596 static void xen_alloc_pud(struct mm_struct *mm, unsigned long pfn)
1598 xen_alloc_ptpage(mm, pfn, PT_PUD);
1601 static void xen_release_pud(unsigned long pfn)
1603 xen_release_ptpage(pfn, PT_PUD);
1607 * Like __va(), but returns address in the kernel mapping (which is
1608 * all we have until the physical memory mapping has been set up.
1610 static void * __init __ka(phys_addr_t paddr)
1612 return (void *)(paddr + __START_KERNEL_map);
1615 /* Convert a machine address to physical address */
1616 static unsigned long __init m2p(phys_addr_t maddr)
1620 maddr &= XEN_PTE_MFN_MASK;
1621 paddr = mfn_to_pfn(maddr >> PAGE_SHIFT) << PAGE_SHIFT;
1626 /* Convert a machine address to kernel virtual */
1627 static void * __init m2v(phys_addr_t maddr)
1629 return __ka(m2p(maddr));
1632 /* Set the page permissions on an identity-mapped pages */
1633 static void __init set_page_prot_flags(void *addr, pgprot_t prot,
1634 unsigned long flags)
1636 unsigned long pfn = __pa(addr) >> PAGE_SHIFT;
1637 pte_t pte = pfn_pte(pfn, prot);
1639 if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, flags))
1642 static void __init set_page_prot(void *addr, pgprot_t prot)
1644 return set_page_prot_flags(addr, prot, UVMF_NONE);
1647 void __init xen_setup_machphys_mapping(void)
1649 struct xen_machphys_mapping mapping;
1651 if (HYPERVISOR_memory_op(XENMEM_machphys_mapping, &mapping) == 0) {
1652 machine_to_phys_mapping = (unsigned long *)mapping.v_start;
1653 machine_to_phys_nr = mapping.max_mfn + 1;
1655 machine_to_phys_nr = MACH2PHYS_NR_ENTRIES;
1659 static void __init convert_pfn_mfn(void *v)
1664 /* All levels are converted the same way, so just treat them
1666 for (i = 0; i < PTRS_PER_PTE; i++)
1667 pte[i] = xen_make_pte(pte[i].pte);
1669 static void __init check_pt_base(unsigned long *pt_base, unsigned long *pt_end,
1672 if (*pt_base == PFN_DOWN(__pa(addr))) {
1673 set_page_prot_flags((void *)addr, PAGE_KERNEL, UVMF_INVLPG);
1674 clear_page((void *)addr);
1677 if (*pt_end == PFN_DOWN(__pa(addr))) {
1678 set_page_prot_flags((void *)addr, PAGE_KERNEL, UVMF_INVLPG);
1679 clear_page((void *)addr);
1684 * Set up the initial kernel pagetable.
1686 * We can construct this by grafting the Xen provided pagetable into
1687 * head_64.S's preconstructed pagetables. We copy the Xen L2's into
1688 * level2_ident_pgt, and level2_kernel_pgt. This means that only the
1689 * kernel has a physical mapping to start with - but that's enough to
1690 * get __va working. We need to fill in the rest of the physical
1691 * mapping once some sort of allocator has been set up.
1693 void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
1697 unsigned long addr[3];
1698 unsigned long pt_base, pt_end;
1701 /* max_pfn_mapped is the last pfn mapped in the initial memory
1702 * mappings. Considering that on Xen after the kernel mappings we
1703 * have the mappings of some pages that don't exist in pfn space, we
1704 * set max_pfn_mapped to the last real pfn mapped. */
1705 if (xen_start_info->mfn_list < __START_KERNEL_map)
1706 max_pfn_mapped = xen_start_info->first_p2m_pfn;
1708 max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));
1710 pt_base = PFN_DOWN(__pa(xen_start_info->pt_base));
1711 pt_end = pt_base + xen_start_info->nr_pt_frames;
1713 /* Zap identity mapping */
1714 init_top_pgt[0] = __pgd(0);
1716 /* Pre-constructed entries are in pfn, so convert to mfn */
1717 /* L4[273] -> level3_ident_pgt */
1718 /* L4[511] -> level3_kernel_pgt */
1719 convert_pfn_mfn(init_top_pgt);
1721 /* L3_i[0] -> level2_ident_pgt */
1722 convert_pfn_mfn(level3_ident_pgt);
1723 /* L3_k[510] -> level2_kernel_pgt */
1724 /* L3_k[511] -> level2_fixmap_pgt */
1725 convert_pfn_mfn(level3_kernel_pgt);
1727 /* L3_k[511][508-FIXMAP_PMD_NUM ... 507] -> level1_fixmap_pgt */
1728 convert_pfn_mfn(level2_fixmap_pgt);
1730 /* We get [511][511] and have Xen's version of level2_kernel_pgt */
1731 l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd);
1732 l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud);
1734 addr[0] = (unsigned long)pgd;
1735 addr[1] = (unsigned long)l3;
1736 addr[2] = (unsigned long)l2;
1737 /* Graft it onto L4[273][0]. Note that we creating an aliasing problem:
1738 * Both L4[273][0] and L4[511][510] have entries that point to the same
1739 * L2 (PMD) tables. Meaning that if you modify it in __va space
1740 * it will be also modified in the __ka space! (But if you just
1741 * modify the PMD table to point to other PTE's or none, then you
1742 * are OK - which is what cleanup_highmap does) */
1743 copy_page(level2_ident_pgt, l2);
1744 /* Graft it onto L4[511][510] */
1745 copy_page(level2_kernel_pgt, l2);
1748 * Zap execute permission from the ident map. Due to the sharing of
1749 * L1 entries we need to do this in the L2.
1751 if (__supported_pte_mask & _PAGE_NX) {
1752 for (i = 0; i < PTRS_PER_PMD; ++i) {
1753 if (pmd_none(level2_ident_pgt[i]))
1755 level2_ident_pgt[i] = pmd_set_flags(level2_ident_pgt[i], _PAGE_NX);
1759 /* Copy the initial P->M table mappings if necessary. */
1760 i = pgd_index(xen_start_info->mfn_list);
1761 if (i && i < pgd_index(__START_KERNEL_map))
1762 init_top_pgt[i] = ((pgd_t *)xen_start_info->pt_base)[i];
1764 /* Make pagetable pieces RO */
1765 set_page_prot(init_top_pgt, PAGE_KERNEL_RO);
1766 set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO);
1767 set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO);
1768 set_page_prot(level2_ident_pgt, PAGE_KERNEL_RO);
1769 set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
1770 set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO);
1772 for (i = 0; i < FIXMAP_PMD_NUM; i++) {
1773 set_page_prot(level1_fixmap_pgt + i * PTRS_PER_PTE,
1777 /* Pin down new L4 */
1778 pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE,
1779 PFN_DOWN(__pa_symbol(init_top_pgt)));
1781 /* Unpin Xen-provided one */
1782 pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
1784 #ifdef CONFIG_X86_VSYSCALL_EMULATION
1785 /* Pin user vsyscall L3 */
1786 set_page_prot(level3_user_vsyscall, PAGE_KERNEL_RO);
1787 pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE,
1788 PFN_DOWN(__pa_symbol(level3_user_vsyscall)));
1792 * At this stage there can be no user pgd, and no page structure to
1793 * attach it to, so make sure we just set kernel pgd.
1796 __xen_write_cr3(true, __pa(init_top_pgt));
1797 xen_mc_issue(PARAVIRT_LAZY_CPU);
1799 /* We can't that easily rip out L3 and L2, as the Xen pagetables are
1800 * set out this way: [L4], [L1], [L2], [L3], [L1], [L1] ... for
1801 * the initial domain. For guests using the toolstack, they are in:
1802 * [L4], [L3], [L2], [L1], [L1], order .. So for dom0 we can only
1803 * rip out the [L4] (pgd), but for guests we shave off three pages.
1805 for (i = 0; i < ARRAY_SIZE(addr); i++)
1806 check_pt_base(&pt_base, &pt_end, addr[i]);
1808 /* Our (by three pages) smaller Xen pagetable that we are using */
1809 xen_pt_base = PFN_PHYS(pt_base);
1810 xen_pt_size = (pt_end - pt_base) * PAGE_SIZE;
1811 memblock_reserve(xen_pt_base, xen_pt_size);
1813 /* Revector the xen_start_info */
1814 xen_start_info = (struct start_info *)__va(__pa(xen_start_info));
1818 * Read a value from a physical address.
1820 static unsigned long __init xen_read_phys_ulong(phys_addr_t addr)
1822 unsigned long *vaddr;
1825 vaddr = early_memremap_ro(addr, sizeof(val));
1827 early_memunmap(vaddr, sizeof(val));
1832 * Translate a virtual address to a physical one without relying on mapped
1833 * page tables. Don't rely on big pages being aligned in (guest) physical
1836 static phys_addr_t __init xen_early_virt_to_phys(unsigned long vaddr)
1845 pgd = native_make_pgd(xen_read_phys_ulong(pa + pgd_index(vaddr) *
1847 if (!pgd_present(pgd))
1850 pa = pgd_val(pgd) & PTE_PFN_MASK;
1851 pud = native_make_pud(xen_read_phys_ulong(pa + pud_index(vaddr) *
1853 if (!pud_present(pud))
1855 pa = pud_val(pud) & PTE_PFN_MASK;
1857 return pa + (vaddr & ~PUD_MASK);
1859 pmd = native_make_pmd(xen_read_phys_ulong(pa + pmd_index(vaddr) *
1861 if (!pmd_present(pmd))
1863 pa = pmd_val(pmd) & PTE_PFN_MASK;
1865 return pa + (vaddr & ~PMD_MASK);
1867 pte = native_make_pte(xen_read_phys_ulong(pa + pte_index(vaddr) *
1869 if (!pte_present(pte))
1871 pa = pte_pfn(pte) << PAGE_SHIFT;
1873 return pa | (vaddr & ~PAGE_MASK);
1877 * Find a new area for the hypervisor supplied p2m list and relocate the p2m to
1880 void __init xen_relocate_p2m(void)
1882 phys_addr_t size, new_area, pt_phys, pmd_phys, pud_phys;
1883 unsigned long p2m_pfn, p2m_pfn_end, n_frames, pfn, pfn_end;
1884 int n_pte, n_pt, n_pmd, n_pud, idx_pte, idx_pt, idx_pmd, idx_pud;
1889 unsigned long *new_p2m;
1891 size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
1892 n_pte = roundup(size, PAGE_SIZE) >> PAGE_SHIFT;
1893 n_pt = roundup(size, PMD_SIZE) >> PMD_SHIFT;
1894 n_pmd = roundup(size, PUD_SIZE) >> PUD_SHIFT;
1895 n_pud = roundup(size, P4D_SIZE) >> P4D_SHIFT;
1896 n_frames = n_pte + n_pt + n_pmd + n_pud;
1898 new_area = xen_find_free_area(PFN_PHYS(n_frames));
1900 xen_raw_console_write("Can't find new memory area for p2m needed due to E820 map conflict\n");
1905 * Setup the page tables for addressing the new p2m list.
1906 * We have asked the hypervisor to map the p2m list at the user address
1907 * PUD_SIZE. It may have done so, or it may have used a kernel space
1908 * address depending on the Xen version.
1909 * To avoid any possible virtual address collision, just use
1910 * 2 * PUD_SIZE for the new area.
1912 pud_phys = new_area;
1913 pmd_phys = pud_phys + PFN_PHYS(n_pud);
1914 pt_phys = pmd_phys + PFN_PHYS(n_pmd);
1915 p2m_pfn = PFN_DOWN(pt_phys) + n_pt;
1917 pgd = __va(read_cr3_pa());
1918 new_p2m = (unsigned long *)(2 * PGDIR_SIZE);
1919 for (idx_pud = 0; idx_pud < n_pud; idx_pud++) {
1920 pud = early_memremap(pud_phys, PAGE_SIZE);
1922 for (idx_pmd = 0; idx_pmd < min(n_pmd, PTRS_PER_PUD);
1924 pmd = early_memremap(pmd_phys, PAGE_SIZE);
1926 for (idx_pt = 0; idx_pt < min(n_pt, PTRS_PER_PMD);
1928 pt = early_memremap(pt_phys, PAGE_SIZE);
1931 idx_pte < min(n_pte, PTRS_PER_PTE);
1933 pt[idx_pte] = pfn_pte(p2m_pfn,
1937 n_pte -= PTRS_PER_PTE;
1938 early_memunmap(pt, PAGE_SIZE);
1939 make_lowmem_page_readonly(__va(pt_phys));
1940 pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE,
1942 pmd[idx_pt] = __pmd(_PAGE_TABLE | pt_phys);
1943 pt_phys += PAGE_SIZE;
1945 n_pt -= PTRS_PER_PMD;
1946 early_memunmap(pmd, PAGE_SIZE);
1947 make_lowmem_page_readonly(__va(pmd_phys));
1948 pin_pagetable_pfn(MMUEXT_PIN_L2_TABLE,
1949 PFN_DOWN(pmd_phys));
1950 pud[idx_pmd] = __pud(_PAGE_TABLE | pmd_phys);
1951 pmd_phys += PAGE_SIZE;
1953 n_pmd -= PTRS_PER_PUD;
1954 early_memunmap(pud, PAGE_SIZE);
1955 make_lowmem_page_readonly(__va(pud_phys));
1956 pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, PFN_DOWN(pud_phys));
1957 set_pgd(pgd + 2 + idx_pud, __pgd(_PAGE_TABLE | pud_phys));
1958 pud_phys += PAGE_SIZE;
1961 /* Now copy the old p2m info to the new area. */
1962 memcpy(new_p2m, xen_p2m_addr, size);
1963 xen_p2m_addr = new_p2m;
1965 /* Release the old p2m list and set new list info. */
1966 p2m_pfn = PFN_DOWN(xen_early_virt_to_phys(xen_start_info->mfn_list));
1968 p2m_pfn_end = p2m_pfn + PFN_DOWN(size);
1970 if (xen_start_info->mfn_list < __START_KERNEL_map) {
1971 pfn = xen_start_info->first_p2m_pfn;
1972 pfn_end = xen_start_info->first_p2m_pfn +
1973 xen_start_info->nr_p2m_frames;
1974 set_pgd(pgd + 1, __pgd(0));
1977 pfn_end = p2m_pfn_end;
1980 memblock_phys_free(PFN_PHYS(pfn), PAGE_SIZE * (pfn_end - pfn));
1981 while (pfn < pfn_end) {
1982 if (pfn == p2m_pfn) {
1986 make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
1990 xen_start_info->mfn_list = (unsigned long)xen_p2m_addr;
1991 xen_start_info->first_p2m_pfn = PFN_DOWN(new_area);
1992 xen_start_info->nr_p2m_frames = n_frames;
1995 void __init xen_reserve_special_pages(void)
1999 memblock_reserve(__pa(xen_start_info), PAGE_SIZE);
2000 if (xen_start_info->store_mfn) {
2001 paddr = PFN_PHYS(mfn_to_pfn(xen_start_info->store_mfn));
2002 memblock_reserve(paddr, PAGE_SIZE);
2004 if (!xen_initial_domain()) {
2005 paddr = PFN_PHYS(mfn_to_pfn(xen_start_info->console.domU.mfn));
2006 memblock_reserve(paddr, PAGE_SIZE);
2010 void __init xen_pt_check_e820(void)
2012 if (xen_is_e820_reserved(xen_pt_base, xen_pt_size)) {
2013 xen_raw_console_write("Xen hypervisor allocated page table memory conflicts with E820 map\n");
2018 static unsigned char dummy_mapping[PAGE_SIZE] __page_aligned_bss;
2020 static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
2023 unsigned long vaddr;
2025 phys >>= PAGE_SHIFT;
2028 case FIX_BTMAP_END ... FIX_BTMAP_BEGIN:
2029 #ifdef CONFIG_X86_VSYSCALL_EMULATION
2032 /* All local page mappings */
2033 pte = pfn_pte(phys, prot);
2036 #ifdef CONFIG_X86_LOCAL_APIC
2037 case FIX_APIC_BASE: /* maps dummy local APIC */
2038 pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
2042 #ifdef CONFIG_X86_IO_APIC
2043 case FIX_IO_APIC_BASE_0 ... FIX_IO_APIC_BASE_END:
2045 * We just don't map the IO APIC - all access is via
2046 * hypercalls. Keep the address in the pte for reference.
2048 pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
2052 case FIX_PARAVIRT_BOOTMAP:
2053 /* This is an MFN, but it isn't an IO mapping from the
2055 pte = mfn_pte(phys, prot);
2059 /* By default, set_fixmap is used for hardware mappings */
2060 pte = mfn_pte(phys, prot);
2064 vaddr = __fix_to_virt(idx);
2065 if (HYPERVISOR_update_va_mapping(vaddr, pte, UVMF_INVLPG))
2068 #ifdef CONFIG_X86_VSYSCALL_EMULATION
2069 /* Replicate changes to map the vsyscall page into the user
2070 pagetable vsyscall mapping. */
2071 if (idx == VSYSCALL_PAGE)
2072 set_pte_vaddr_pud(level3_user_vsyscall, vaddr, pte);
2076 static void __init xen_post_allocator_init(void)
2078 pv_ops.mmu.set_pte = xen_set_pte;
2079 pv_ops.mmu.set_pmd = xen_set_pmd;
2080 pv_ops.mmu.set_pud = xen_set_pud;
2081 pv_ops.mmu.set_p4d = xen_set_p4d;
2083 /* This will work as long as patching hasn't happened yet
2084 (which it hasn't) */
2085 pv_ops.mmu.alloc_pte = xen_alloc_pte;
2086 pv_ops.mmu.alloc_pmd = xen_alloc_pmd;
2087 pv_ops.mmu.release_pte = xen_release_pte;
2088 pv_ops.mmu.release_pmd = xen_release_pmd;
2089 pv_ops.mmu.alloc_pud = xen_alloc_pud;
2090 pv_ops.mmu.release_pud = xen_release_pud;
2091 pv_ops.mmu.make_pte = PV_CALLEE_SAVE(xen_make_pte);
2093 pv_ops.mmu.write_cr3 = &xen_write_cr3;
2096 static void xen_leave_lazy_mmu(void)
2100 paravirt_leave_lazy_mmu();
2104 static const typeof(pv_ops) xen_mmu_ops __initconst = {
2106 .read_cr2 = __PV_IS_CALLEE_SAVE(xen_read_cr2),
2107 .write_cr2 = xen_write_cr2,
2109 .read_cr3 = xen_read_cr3,
2110 .write_cr3 = xen_write_cr3_init,
2112 .flush_tlb_user = xen_flush_tlb,
2113 .flush_tlb_kernel = xen_flush_tlb,
2114 .flush_tlb_one_user = xen_flush_tlb_one_user,
2115 .flush_tlb_multi = xen_flush_tlb_multi,
2116 .tlb_remove_table = tlb_remove_table,
2118 .pgd_alloc = xen_pgd_alloc,
2119 .pgd_free = xen_pgd_free,
2121 .alloc_pte = xen_alloc_pte_init,
2122 .release_pte = xen_release_pte_init,
2123 .alloc_pmd = xen_alloc_pmd_init,
2124 .release_pmd = xen_release_pmd_init,
2126 .set_pte = xen_set_pte_init,
2127 .set_pmd = xen_set_pmd_hyper,
2129 .ptep_modify_prot_start = xen_ptep_modify_prot_start,
2130 .ptep_modify_prot_commit = xen_ptep_modify_prot_commit,
2132 .pte_val = PV_CALLEE_SAVE(xen_pte_val),
2133 .pgd_val = PV_CALLEE_SAVE(xen_pgd_val),
2135 .make_pte = PV_CALLEE_SAVE(xen_make_pte_init),
2136 .make_pgd = PV_CALLEE_SAVE(xen_make_pgd),
2138 .set_pud = xen_set_pud_hyper,
2140 .make_pmd = PV_CALLEE_SAVE(xen_make_pmd),
2141 .pmd_val = PV_CALLEE_SAVE(xen_pmd_val),
2143 .pud_val = PV_CALLEE_SAVE(xen_pud_val),
2144 .make_pud = PV_CALLEE_SAVE(xen_make_pud),
2145 .set_p4d = xen_set_p4d_hyper,
2147 .alloc_pud = xen_alloc_pmd_init,
2148 .release_pud = xen_release_pmd_init,
2150 #if CONFIG_PGTABLE_LEVELS >= 5
2151 .p4d_val = PV_CALLEE_SAVE(xen_p4d_val),
2152 .make_p4d = PV_CALLEE_SAVE(xen_make_p4d),
2155 .activate_mm = xen_activate_mm,
2156 .dup_mmap = xen_dup_mmap,
2157 .exit_mmap = xen_exit_mmap,
2160 .enter = paravirt_enter_lazy_mmu,
2161 .leave = xen_leave_lazy_mmu,
2162 .flush = paravirt_flush_lazy_mmu,
2165 .set_fixmap = xen_set_fixmap,
2169 void __init xen_init_mmu_ops(void)
2171 x86_init.paging.pagetable_init = xen_pagetable_init;
2172 x86_init.hyper.init_after_bootmem = xen_after_bootmem;
2174 pv_ops.mmu = xen_mmu_ops.mmu;
2176 memset(dummy_mapping, 0xff, PAGE_SIZE);
2179 /* Protected by xen_reservation_lock. */
2180 #define MAX_CONTIG_ORDER 9 /* 2MB */
2181 static unsigned long discontig_frames[1<<MAX_CONTIG_ORDER];
2183 #define VOID_PTE (mfn_pte(0, __pgprot(0)))
2184 static void xen_zap_pfn_range(unsigned long vaddr, unsigned int order,
2185 unsigned long *in_frames,
2186 unsigned long *out_frames)
2189 struct multicall_space mcs;
2192 for (i = 0; i < (1UL<<order); i++, vaddr += PAGE_SIZE) {
2193 mcs = __xen_mc_entry(0);
2196 in_frames[i] = virt_to_mfn(vaddr);
2198 MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0);
2199 __set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);
2202 out_frames[i] = virt_to_pfn(vaddr);
2208 * Update the pfn-to-mfn mappings for a virtual address range, either to
2209 * point to an array of mfns, or contiguously from a single starting
2212 static void xen_remap_exchanged_ptes(unsigned long vaddr, int order,
2213 unsigned long *mfns,
2214 unsigned long first_mfn)
2221 limit = 1u << order;
2222 for (i = 0; i < limit; i++, vaddr += PAGE_SIZE) {
2223 struct multicall_space mcs;
2226 mcs = __xen_mc_entry(0);
2230 mfn = first_mfn + i;
2232 if (i < (limit - 1))
2236 flags = UVMF_INVLPG | UVMF_ALL;
2238 flags = UVMF_TLB_FLUSH | UVMF_ALL;
2241 MULTI_update_va_mapping(mcs.mc, vaddr,
2242 mfn_pte(mfn, PAGE_KERNEL), flags);
2244 set_phys_to_machine(virt_to_pfn(vaddr), mfn);
2251 * Perform the hypercall to exchange a region of our pfns to point to
2252 * memory with the required contiguous alignment. Takes the pfns as
2253 * input, and populates mfns as output.
2255 * Returns a success code indicating whether the hypervisor was able to
2256 * satisfy the request or not.
2258 static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in,
2259 unsigned long *pfns_in,
2260 unsigned long extents_out,
2261 unsigned int order_out,
2262 unsigned long *mfns_out,
2263 unsigned int address_bits)
2268 struct xen_memory_exchange exchange = {
2270 .nr_extents = extents_in,
2271 .extent_order = order_in,
2272 .extent_start = pfns_in,
2276 .nr_extents = extents_out,
2277 .extent_order = order_out,
2278 .extent_start = mfns_out,
2279 .address_bits = address_bits,
2284 BUG_ON(extents_in << order_in != extents_out << order_out);
2286 rc = HYPERVISOR_memory_op(XENMEM_exchange, &exchange);
2287 success = (exchange.nr_exchanged == extents_in);
2289 BUG_ON(!success && ((exchange.nr_exchanged != 0) || (rc == 0)));
2290 BUG_ON(success && (rc != 0));
2295 int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
2296 unsigned int address_bits,
2297 dma_addr_t *dma_handle)
2299 unsigned long *in_frames = discontig_frames, out_frame;
2300 unsigned long flags;
2302 unsigned long vstart = (unsigned long)phys_to_virt(pstart);
2305 * Currently an auto-translated guest will not perform I/O, nor will
2306 * it require PAE page directories below 4GB. Therefore any calls to
2307 * this function are redundant and can be ignored.
2310 if (unlikely(order > MAX_CONTIG_ORDER))
2313 memset((void *) vstart, 0, PAGE_SIZE << order);
2315 spin_lock_irqsave(&xen_reservation_lock, flags);
2317 /* 1. Zap current PTEs, remembering MFNs. */
2318 xen_zap_pfn_range(vstart, order, in_frames, NULL);
2320 /* 2. Get a new contiguous memory extent. */
2321 out_frame = virt_to_pfn(vstart);
2322 success = xen_exchange_memory(1UL << order, 0, in_frames,
2323 1, order, &out_frame,
2326 /* 3. Map the new extent in place of old pages. */
2328 xen_remap_exchanged_ptes(vstart, order, NULL, out_frame);
2330 xen_remap_exchanged_ptes(vstart, order, in_frames, 0);
2332 spin_unlock_irqrestore(&xen_reservation_lock, flags);
2334 *dma_handle = virt_to_machine(vstart).maddr;
2335 return success ? 0 : -ENOMEM;
2338 void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)
2340 unsigned long *out_frames = discontig_frames, in_frame;
2341 unsigned long flags;
2343 unsigned long vstart;
2345 if (unlikely(order > MAX_CONTIG_ORDER))
2348 vstart = (unsigned long)phys_to_virt(pstart);
2349 memset((void *) vstart, 0, PAGE_SIZE << order);
2351 spin_lock_irqsave(&xen_reservation_lock, flags);
2353 /* 1. Find start MFN of contiguous extent. */
2354 in_frame = virt_to_mfn(vstart);
2356 /* 2. Zap current PTEs. */
2357 xen_zap_pfn_range(vstart, order, NULL, out_frames);
2359 /* 3. Do the exchange for non-contiguous MFNs. */
2360 success = xen_exchange_memory(1, order, &in_frame, 1UL << order,
2363 /* 4. Map new pages in place of old pages. */
2365 xen_remap_exchanged_ptes(vstart, order, out_frames, 0);
2367 xen_remap_exchanged_ptes(vstart, order, NULL, in_frame);
2369 spin_unlock_irqrestore(&xen_reservation_lock, flags);
2372 static noinline void xen_flush_tlb_all(void)
2374 struct mmuext_op *op;
2375 struct multicall_space mcs;
2379 mcs = xen_mc_entry(sizeof(*op));
2382 op->cmd = MMUEXT_TLB_FLUSH_ALL;
2383 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
2385 xen_mc_issue(PARAVIRT_LAZY_MMU);
2390 #define REMAP_BATCH_SIZE 16
2397 struct mmu_update *mmu_update;
2400 static int remap_area_pfn_pte_fn(pte_t *ptep, unsigned long addr, void *data)
2402 struct remap_data *rmd = data;
2403 pte_t pte = pte_mkspecial(mfn_pte(*rmd->pfn, rmd->prot));
2406 * If we have a contiguous range, just update the pfn itself,
2407 * else update pointer to be "next pfn".
2409 if (rmd->contiguous)
2414 rmd->mmu_update->ptr = virt_to_machine(ptep).maddr;
2415 rmd->mmu_update->ptr |= rmd->no_translate ?
2416 MMU_PT_UPDATE_NO_TRANSLATE :
2417 MMU_NORMAL_PT_UPDATE;
2418 rmd->mmu_update->val = pte_val_ma(pte);
2424 int xen_remap_pfn(struct vm_area_struct *vma, unsigned long addr,
2425 xen_pfn_t *pfn, int nr, int *err_ptr, pgprot_t prot,
2426 unsigned int domid, bool no_translate)
2429 struct remap_data rmd;
2430 struct mmu_update mmu_update[REMAP_BATCH_SIZE];
2431 unsigned long range;
2434 BUG_ON(!((vma->vm_flags & (VM_PFNMAP | VM_IO)) == (VM_PFNMAP | VM_IO)));
2439 * We use the err_ptr to indicate if there we are doing a contiguous
2440 * mapping or a discontiguous mapping.
2442 rmd.contiguous = !err_ptr;
2443 rmd.no_translate = no_translate;
2448 int batch = min(REMAP_BATCH_SIZE, nr);
2449 int batch_left = batch;
2451 range = (unsigned long)batch << PAGE_SHIFT;
2453 rmd.mmu_update = mmu_update;
2454 err = apply_to_page_range(vma->vm_mm, addr, range,
2455 remap_area_pfn_pte_fn, &rmd);
2460 * We record the error for each page that gives an error, but
2461 * continue mapping until the whole set is done
2466 err = HYPERVISOR_mmu_update(&mmu_update[index],
2467 batch_left, &done, domid);
2470 * @err_ptr may be the same buffer as @gfn, so
2471 * only clear it after each chunk of @gfn is
2475 for (i = index; i < index + done; i++)
2482 done++; /* Skip failed frame. */
2487 } while (batch_left);
2497 xen_flush_tlb_all();
2499 return err < 0 ? err : mapped;
2501 EXPORT_SYMBOL_GPL(xen_remap_pfn);
2503 #ifdef CONFIG_KEXEC_CORE
2504 phys_addr_t paddr_vmcoreinfo_note(void)
2506 if (xen_pv_domain())
2507 return virt_to_machine(vmcoreinfo_note).maddr;
2509 return __pa(vmcoreinfo_note);
2511 #endif /* CONFIG_KEXEC_CORE */