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authorAnton Arapov <anton@redhat.com>2012-04-16 10:05:28 +0200
committerAnton Arapov <anton@redhat.com>2012-04-16 10:05:28 +0200
commitb4b6116a13633898cf868f2f103c96a90c4c20f8 (patch)
tree93d1b7e2cfcdf473d8d4ff3ad141fa864f8491f6 /arch/x86/xen/mmu.c
parentedd4be777c953e5faafc80d091d3084b4343f5d3 (diff)
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fedora kernel: d9aad82f3319f3cfd1aebc01234254ef0c37ad84v3.3.2-1
Signed-off-by: Anton Arapov <anton@redhat.com>
Diffstat (limited to 'arch/x86/xen/mmu.c')
-rw-r--r--arch/x86/xen/mmu.c2364
1 files changed, 2364 insertions, 0 deletions
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
new file mode 100644
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+++ b/arch/x86/xen/mmu.c
@@ -0,0 +1,2364 @@
+/*
+ * Xen mmu operations
+ *
+ * This file contains the various mmu fetch and update operations.
+ * The most important job they must perform is the mapping between the
+ * domain's pfn and the overall machine mfns.
+ *
+ * Xen allows guests to directly update the pagetable, in a controlled
+ * fashion. In other words, the guest modifies the same pagetable
+ * that the CPU actually uses, which eliminates the overhead of having
+ * a separate shadow pagetable.
+ *
+ * In order to allow this, it falls on the guest domain to map its
+ * notion of a "physical" pfn - which is just a domain-local linear
+ * address - into a real "machine address" which the CPU's MMU can
+ * use.
+ *
+ * A pgd_t/pmd_t/pte_t will typically contain an mfn, and so can be
+ * inserted directly into the pagetable. When creating a new
+ * pte/pmd/pgd, it converts the passed pfn into an mfn. Conversely,
+ * when reading the content back with __(pgd|pmd|pte)_val, it converts
+ * the mfn back into a pfn.
+ *
+ * The other constraint is that all pages which make up a pagetable
+ * must be mapped read-only in the guest. This prevents uncontrolled
+ * guest updates to the pagetable. Xen strictly enforces this, and
+ * will disallow any pagetable update which will end up mapping a
+ * pagetable page RW, and will disallow using any writable page as a
+ * pagetable.
+ *
+ * Naively, when loading %cr3 with the base of a new pagetable, Xen
+ * would need to validate the whole pagetable before going on.
+ * Naturally, this is quite slow. The solution is to "pin" a
+ * pagetable, which enforces all the constraints on the pagetable even
+ * when it is not actively in use. This menas that Xen can be assured
+ * that it is still valid when you do load it into %cr3, and doesn't
+ * need to revalidate it.
+ *
+ * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
+ */
+#include <linux/sched.h>
+#include <linux/highmem.h>
+#include <linux/debugfs.h>
+#include <linux/bug.h>
+#include <linux/vmalloc.h>
+#include <linux/module.h>
+#include <linux/gfp.h>
+#include <linux/memblock.h>
+#include <linux/seq_file.h>
+
+#include <trace/events/xen.h>
+
+#include <asm/pgtable.h>
+#include <asm/tlbflush.h>
+#include <asm/fixmap.h>
+#include <asm/mmu_context.h>
+#include <asm/setup.h>
+#include <asm/paravirt.h>
+#include <asm/e820.h>
+#include <asm/linkage.h>
+#include <asm/page.h>
+#include <asm/init.h>
+#include <asm/pat.h>
+#include <asm/smp.h>
+
+#include <asm/xen/hypercall.h>
+#include <asm/xen/hypervisor.h>
+
+#include <xen/xen.h>
+#include <xen/page.h>
+#include <xen/interface/xen.h>
+#include <xen/interface/hvm/hvm_op.h>
+#include <xen/interface/version.h>
+#include <xen/interface/memory.h>
+#include <xen/hvc-console.h>
+
+#include "multicalls.h"
+#include "mmu.h"
+#include "debugfs.h"
+
+/*
+ * Protects atomic reservation decrease/increase against concurrent increases.
+ * Also protects non-atomic updates of current_pages and balloon lists.
+ */
+DEFINE_SPINLOCK(xen_reservation_lock);
+
+/*
+ * Identity map, in addition to plain kernel map. This needs to be
+ * large enough to allocate page table pages to allocate the rest.
+ * Each page can map 2MB.
+ */
+#define LEVEL1_IDENT_ENTRIES (PTRS_PER_PTE * 4)
+static RESERVE_BRK_ARRAY(pte_t, level1_ident_pgt, LEVEL1_IDENT_ENTRIES);
+
+#ifdef CONFIG_X86_64
+/* l3 pud for userspace vsyscall mapping */
+static pud_t level3_user_vsyscall[PTRS_PER_PUD] __page_aligned_bss;
+#endif /* CONFIG_X86_64 */
+
+/*
+ * Note about cr3 (pagetable base) values:
+ *
+ * xen_cr3 contains the current logical cr3 value; it contains the
+ * last set cr3. This may not be the current effective cr3, because
+ * its update may be being lazily deferred. However, a vcpu looking
+ * at its own cr3 can use this value knowing that it everything will
+ * be self-consistent.
+ *
+ * xen_current_cr3 contains the actual vcpu cr3; it is set once the
+ * hypercall to set the vcpu cr3 is complete (so it may be a little
+ * out of date, but it will never be set early). If one vcpu is
+ * looking at another vcpu's cr3 value, it should use this variable.
+ */
+DEFINE_PER_CPU(unsigned long, xen_cr3); /* cr3 stored as physaddr */
+DEFINE_PER_CPU(unsigned long, xen_current_cr3); /* actual vcpu cr3 */
+
+
+/*
+ * Just beyond the highest usermode address. STACK_TOP_MAX has a
+ * redzone above it, so round it up to a PGD boundary.
+ */
+#define USER_LIMIT ((STACK_TOP_MAX + PGDIR_SIZE - 1) & PGDIR_MASK)
+
+unsigned long arbitrary_virt_to_mfn(void *vaddr)
+{
+ xmaddr_t maddr = arbitrary_virt_to_machine(vaddr);
+
+ return PFN_DOWN(maddr.maddr);
+}
+
+xmaddr_t arbitrary_virt_to_machine(void *vaddr)
+{
+ unsigned long address = (unsigned long)vaddr;
+ unsigned int level;
+ pte_t *pte;
+ unsigned offset;
+
+ /*
+ * if the PFN is in the linear mapped vaddr range, we can just use
+ * the (quick) virt_to_machine() p2m lookup
+ */
+ if (virt_addr_valid(vaddr))
+ return virt_to_machine(vaddr);
+
+ /* otherwise we have to do a (slower) full page-table walk */
+
+ pte = lookup_address(address, &level);
+ BUG_ON(pte == NULL);
+ offset = address & ~PAGE_MASK;
+ return XMADDR(((phys_addr_t)pte_mfn(*pte) << PAGE_SHIFT) + offset);
+}
+EXPORT_SYMBOL_GPL(arbitrary_virt_to_machine);
+
+void make_lowmem_page_readonly(void *vaddr)
+{
+ pte_t *pte, ptev;
+ unsigned long address = (unsigned long)vaddr;
+ unsigned int level;
+
+ pte = lookup_address(address, &level);
+ if (pte == NULL)
+ return; /* vaddr missing */
+
+ ptev = pte_wrprotect(*pte);
+
+ if (HYPERVISOR_update_va_mapping(address, ptev, 0))
+ BUG();
+}
+
+void make_lowmem_page_readwrite(void *vaddr)
+{
+ pte_t *pte, ptev;
+ unsigned long address = (unsigned long)vaddr;
+ unsigned int level;
+
+ pte = lookup_address(address, &level);
+ if (pte == NULL)
+ return; /* vaddr missing */
+
+ ptev = pte_mkwrite(*pte);
+
+ if (HYPERVISOR_update_va_mapping(address, ptev, 0))
+ BUG();
+}
+
+
+static bool xen_page_pinned(void *ptr)
+{
+ struct page *page = virt_to_page(ptr);
+
+ return PagePinned(page);
+}
+
+void xen_set_domain_pte(pte_t *ptep, pte_t pteval, unsigned domid)
+{
+ struct multicall_space mcs;
+ struct mmu_update *u;
+
+ trace_xen_mmu_set_domain_pte(ptep, pteval, domid);
+
+ mcs = xen_mc_entry(sizeof(*u));
+ u = mcs.args;
+
+ /* ptep might be kmapped when using 32-bit HIGHPTE */
+ u->ptr = virt_to_machine(ptep).maddr;
+ u->val = pte_val_ma(pteval);
+
+ MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, domid);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+}
+EXPORT_SYMBOL_GPL(xen_set_domain_pte);
+
+static void xen_extend_mmu_update(const struct mmu_update *update)
+{
+ struct multicall_space mcs;
+ struct mmu_update *u;
+
+ mcs = xen_mc_extend_args(__HYPERVISOR_mmu_update, sizeof(*u));
+
+ if (mcs.mc != NULL) {
+ mcs.mc->args[1]++;
+ } else {
+ mcs = __xen_mc_entry(sizeof(*u));
+ MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
+ }
+
+ u = mcs.args;
+ *u = *update;
+}
+
+static void xen_extend_mmuext_op(const struct mmuext_op *op)
+{
+ struct multicall_space mcs;
+ struct mmuext_op *u;
+
+ mcs = xen_mc_extend_args(__HYPERVISOR_mmuext_op, sizeof(*u));
+
+ if (mcs.mc != NULL) {
+ mcs.mc->args[1]++;
+ } else {
+ mcs = __xen_mc_entry(sizeof(*u));
+ MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
+ }
+
+ u = mcs.args;
+ *u = *op;
+}
+
+static void xen_set_pmd_hyper(pmd_t *ptr, pmd_t val)
+{
+ struct mmu_update u;
+
+ preempt_disable();
+
+ xen_mc_batch();
+
+ /* ptr may be ioremapped for 64-bit pagetable setup */
+ u.ptr = arbitrary_virt_to_machine(ptr).maddr;
+ u.val = pmd_val_ma(val);
+ xen_extend_mmu_update(&u);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+
+ preempt_enable();
+}
+
+static void xen_set_pmd(pmd_t *ptr, pmd_t val)
+{
+ trace_xen_mmu_set_pmd(ptr, val);
+
+ /* If page is not pinned, we can just update the entry
+ directly */
+ if (!xen_page_pinned(ptr)) {
+ *ptr = val;
+ return;
+ }
+
+ xen_set_pmd_hyper(ptr, val);
+}
+
+/*
+ * Associate a virtual page frame with a given physical page frame
+ * and protection flags for that frame.
+ */
+void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags)
+{
+ set_pte_vaddr(vaddr, mfn_pte(mfn, flags));
+}
+
+static bool xen_batched_set_pte(pte_t *ptep, pte_t pteval)
+{
+ struct mmu_update u;
+
+ if (paravirt_get_lazy_mode() != PARAVIRT_LAZY_MMU)
+ return false;
+
+ xen_mc_batch();
+
+ u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE;
+ u.val = pte_val_ma(pteval);
+ xen_extend_mmu_update(&u);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+
+ return true;
+}
+
+static inline void __xen_set_pte(pte_t *ptep, pte_t pteval)
+{
+ if (!xen_batched_set_pte(ptep, pteval))
+ native_set_pte(ptep, pteval);
+}
+
+static void xen_set_pte(pte_t *ptep, pte_t pteval)
+{
+ trace_xen_mmu_set_pte(ptep, pteval);
+ __xen_set_pte(ptep, pteval);
+}
+
+static void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, pte_t pteval)
+{
+ trace_xen_mmu_set_pte_at(mm, addr, ptep, pteval);
+ __xen_set_pte(ptep, pteval);
+}
+
+pte_t xen_ptep_modify_prot_start(struct mm_struct *mm,
+ unsigned long addr, pte_t *ptep)
+{
+ /* Just return the pte as-is. We preserve the bits on commit */
+ trace_xen_mmu_ptep_modify_prot_start(mm, addr, ptep, *ptep);
+ return *ptep;
+}
+
+void xen_ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, pte_t pte)
+{
+ struct mmu_update u;
+
+ trace_xen_mmu_ptep_modify_prot_commit(mm, addr, ptep, pte);
+ xen_mc_batch();
+
+ u.ptr = virt_to_machine(ptep).maddr | MMU_PT_UPDATE_PRESERVE_AD;
+ u.val = pte_val_ma(pte);
+ xen_extend_mmu_update(&u);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+}
+
+/* Assume pteval_t is equivalent to all the other *val_t types. */
+static pteval_t pte_mfn_to_pfn(pteval_t val)
+{
+ if (val & _PAGE_PRESENT) {
+ unsigned long mfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
+ pteval_t flags = val & PTE_FLAGS_MASK;
+ val = ((pteval_t)mfn_to_pfn(mfn) << PAGE_SHIFT) | flags;
+ }
+
+ return val;
+}
+
+static pteval_t pte_pfn_to_mfn(pteval_t val)
+{
+ if (val & _PAGE_PRESENT) {
+ unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
+ pteval_t flags = val & PTE_FLAGS_MASK;
+ unsigned long mfn;
+
+ if (!xen_feature(XENFEAT_auto_translated_physmap))
+ mfn = get_phys_to_machine(pfn);
+ else
+ mfn = pfn;
+ /*
+ * If there's no mfn for the pfn, then just create an
+ * empty non-present pte. Unfortunately this loses
+ * information about the original pfn, so
+ * pte_mfn_to_pfn is asymmetric.
+ */
+ if (unlikely(mfn == INVALID_P2M_ENTRY)) {
+ mfn = 0;
+ flags = 0;
+ } else {
+ /*
+ * Paramount to do this test _after_ the
+ * INVALID_P2M_ENTRY as INVALID_P2M_ENTRY &
+ * IDENTITY_FRAME_BIT resolves to true.
+ */
+ mfn &= ~FOREIGN_FRAME_BIT;
+ if (mfn & IDENTITY_FRAME_BIT) {
+ mfn &= ~IDENTITY_FRAME_BIT;
+ flags |= _PAGE_IOMAP;
+ }
+ }
+ val = ((pteval_t)mfn << PAGE_SHIFT) | flags;
+ }
+
+ return val;
+}
+
+static pteval_t iomap_pte(pteval_t val)
+{
+ if (val & _PAGE_PRESENT) {
+ unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
+ pteval_t flags = val & PTE_FLAGS_MASK;
+
+ /* We assume the pte frame number is a MFN, so
+ just use it as-is. */
+ val = ((pteval_t)pfn << PAGE_SHIFT) | flags;
+ }
+
+ return val;
+}
+
+static pteval_t xen_pte_val(pte_t pte)
+{
+ pteval_t pteval = pte.pte;
+#if 0
+ /* If this is a WC pte, convert back from Xen WC to Linux WC */
+ if ((pteval & (_PAGE_PAT | _PAGE_PCD | _PAGE_PWT)) == _PAGE_PAT) {
+ WARN_ON(!pat_enabled);
+ pteval = (pteval & ~_PAGE_PAT) | _PAGE_PWT;
+ }
+#endif
+ if (xen_initial_domain() && (pteval & _PAGE_IOMAP))
+ return pteval;
+
+ return pte_mfn_to_pfn(pteval);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val);
+
+static pgdval_t xen_pgd_val(pgd_t pgd)
+{
+ return pte_mfn_to_pfn(pgd.pgd);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_pgd_val);
+
+/*
+ * Xen's PAT setup is part of its ABI, though I assume entries 6 & 7
+ * are reserved for now, to correspond to the Intel-reserved PAT
+ * types.
+ *
+ * We expect Linux's PAT set as follows:
+ *
+ * Idx PTE flags Linux Xen Default
+ * 0 WB WB WB
+ * 1 PWT WC WT WT
+ * 2 PCD UC- UC- UC-
+ * 3 PCD PWT UC UC UC
+ * 4 PAT WB WC WB
+ * 5 PAT PWT WC WP WT
+ * 6 PAT PCD UC- UC UC-
+ * 7 PAT PCD PWT UC UC UC
+ */
+
+void xen_set_pat(u64 pat)
+{
+ /* We expect Linux to use a PAT setting of
+ * UC UC- WC WB (ignoring the PAT flag) */
+ WARN_ON(pat != 0x0007010600070106ull);
+}
+
+static pte_t xen_make_pte(pteval_t pte)
+{
+ phys_addr_t addr = (pte & PTE_PFN_MASK);
+#if 0
+ /* If Linux is trying to set a WC pte, then map to the Xen WC.
+ * If _PAGE_PAT is set, then it probably means it is really
+ * _PAGE_PSE, so avoid fiddling with the PAT mapping and hope
+ * things work out OK...
+ *
+ * (We should never see kernel mappings with _PAGE_PSE set,
+ * but we could see hugetlbfs mappings, I think.).
+ */
+ if (pat_enabled && !WARN_ON(pte & _PAGE_PAT)) {
+ if ((pte & (_PAGE_PCD | _PAGE_PWT)) == _PAGE_PWT)
+ pte = (pte & ~(_PAGE_PCD | _PAGE_PWT)) | _PAGE_PAT;
+ }
+#endif
+ /*
+ * Unprivileged domains are allowed to do IOMAPpings for
+ * PCI passthrough, but not map ISA space. The ISA
+ * mappings are just dummy local mappings to keep other
+ * parts of the kernel happy.
+ */
+ if (unlikely(pte & _PAGE_IOMAP) &&
+ (xen_initial_domain() || addr >= ISA_END_ADDRESS)) {
+ pte = iomap_pte(pte);
+ } else {
+ pte &= ~_PAGE_IOMAP;
+ pte = pte_pfn_to_mfn(pte);
+ }
+
+ return native_make_pte(pte);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte);
+
+static pgd_t xen_make_pgd(pgdval_t pgd)
+{
+ pgd = pte_pfn_to_mfn(pgd);
+ return native_make_pgd(pgd);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_make_pgd);
+
+static pmdval_t xen_pmd_val(pmd_t pmd)
+{
+ return pte_mfn_to_pfn(pmd.pmd);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_pmd_val);
+
+static void xen_set_pud_hyper(pud_t *ptr, pud_t val)
+{
+ struct mmu_update u;
+
+ preempt_disable();
+
+ xen_mc_batch();
+
+ /* ptr may be ioremapped for 64-bit pagetable setup */
+ u.ptr = arbitrary_virt_to_machine(ptr).maddr;
+ u.val = pud_val_ma(val);
+ xen_extend_mmu_update(&u);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+
+ preempt_enable();
+}
+
+static void xen_set_pud(pud_t *ptr, pud_t val)
+{
+ trace_xen_mmu_set_pud(ptr, val);
+
+ /* If page is not pinned, we can just update the entry
+ directly */
+ if (!xen_page_pinned(ptr)) {
+ *ptr = val;
+ return;
+ }
+
+ xen_set_pud_hyper(ptr, val);
+}
+
+#ifdef CONFIG_X86_PAE
+static void xen_set_pte_atomic(pte_t *ptep, pte_t pte)
+{
+ trace_xen_mmu_set_pte_atomic(ptep, pte);
+ set_64bit((u64 *)ptep, native_pte_val(pte));
+}
+
+static void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
+{
+ trace_xen_mmu_pte_clear(mm, addr, ptep);
+ if (!xen_batched_set_pte(ptep, native_make_pte(0)))
+ native_pte_clear(mm, addr, ptep);
+}
+
+static void xen_pmd_clear(pmd_t *pmdp)
+{
+ trace_xen_mmu_pmd_clear(pmdp);
+ set_pmd(pmdp, __pmd(0));
+}
+#endif /* CONFIG_X86_PAE */
+
+static pmd_t xen_make_pmd(pmdval_t pmd)
+{
+ pmd = pte_pfn_to_mfn(pmd);
+ return native_make_pmd(pmd);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_make_pmd);
+
+#if PAGETABLE_LEVELS == 4
+static pudval_t xen_pud_val(pud_t pud)
+{
+ return pte_mfn_to_pfn(pud.pud);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_pud_val);
+
+static pud_t xen_make_pud(pudval_t pud)
+{
+ pud = pte_pfn_to_mfn(pud);
+
+ return native_make_pud(pud);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_make_pud);
+
+static pgd_t *xen_get_user_pgd(pgd_t *pgd)
+{
+ pgd_t *pgd_page = (pgd_t *)(((unsigned long)pgd) & PAGE_MASK);
+ unsigned offset = pgd - pgd_page;
+ pgd_t *user_ptr = NULL;
+
+ if (offset < pgd_index(USER_LIMIT)) {
+ struct page *page = virt_to_page(pgd_page);
+ user_ptr = (pgd_t *)page->private;
+ if (user_ptr)
+ user_ptr += offset;
+ }
+
+ return user_ptr;
+}
+
+static void __xen_set_pgd_hyper(pgd_t *ptr, pgd_t val)
+{
+ struct mmu_update u;
+
+ u.ptr = virt_to_machine(ptr).maddr;
+ u.val = pgd_val_ma(val);
+ xen_extend_mmu_update(&u);
+}
+
+/*
+ * Raw hypercall-based set_pgd, intended for in early boot before
+ * there's a page structure. This implies:
+ * 1. The only existing pagetable is the kernel's
+ * 2. It is always pinned
+ * 3. It has no user pagetable attached to it
+ */
+static void __init xen_set_pgd_hyper(pgd_t *ptr, pgd_t val)
+{
+ preempt_disable();
+
+ xen_mc_batch();
+
+ __xen_set_pgd_hyper(ptr, val);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+
+ preempt_enable();
+}
+
+static void xen_set_pgd(pgd_t *ptr, pgd_t val)
+{
+ pgd_t *user_ptr = xen_get_user_pgd(ptr);
+
+ trace_xen_mmu_set_pgd(ptr, user_ptr, val);
+
+ /* If page is not pinned, we can just update the entry
+ directly */
+ if (!xen_page_pinned(ptr)) {
+ *ptr = val;
+ if (user_ptr) {
+ WARN_ON(xen_page_pinned(user_ptr));
+ *user_ptr = val;
+ }
+ return;
+ }
+
+ /* If it's pinned, then we can at least batch the kernel and
+ user updates together. */
+ xen_mc_batch();
+
+ __xen_set_pgd_hyper(ptr, val);
+ if (user_ptr)
+ __xen_set_pgd_hyper(user_ptr, val);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+}
+#endif /* PAGETABLE_LEVELS == 4 */
+
+/*
+ * (Yet another) pagetable walker. This one is intended for pinning a
+ * pagetable. This means that it walks a pagetable and calls the
+ * callback function on each page it finds making up the page table,
+ * at every level. It walks the entire pagetable, but it only bothers
+ * pinning pte pages which are below limit. In the normal case this
+ * will be STACK_TOP_MAX, but at boot we need to pin up to
+ * FIXADDR_TOP.
+ *
+ * For 32-bit the important bit is that we don't pin beyond there,
+ * because then we start getting into Xen's ptes.
+ *
+ * For 64-bit, we must skip the Xen hole in the middle of the address
+ * space, just after the big x86-64 virtual hole.
+ */
+static int __xen_pgd_walk(struct mm_struct *mm, pgd_t *pgd,
+ int (*func)(struct mm_struct *mm, struct page *,
+ enum pt_level),
+ unsigned long limit)
+{
+ int flush = 0;
+ unsigned hole_low, hole_high;
+ unsigned pgdidx_limit, pudidx_limit, pmdidx_limit;
+ unsigned pgdidx, pudidx, pmdidx;
+
+ /* The limit is the last byte to be touched */
+ limit--;
+ BUG_ON(limit >= FIXADDR_TOP);
+
+ if (xen_feature(XENFEAT_auto_translated_physmap))
+ return 0;
+
+ /*
+ * 64-bit has a great big hole in the middle of the address
+ * space, which contains the Xen mappings. On 32-bit these
+ * will end up making a zero-sized hole and so is a no-op.
+ */
+ hole_low = pgd_index(USER_LIMIT);
+ hole_high = pgd_index(PAGE_OFFSET);
+
+ pgdidx_limit = pgd_index(limit);
+#if PTRS_PER_PUD > 1
+ pudidx_limit = pud_index(limit);
+#else
+ pudidx_limit = 0;
+#endif
+#if PTRS_PER_PMD > 1
+ pmdidx_limit = pmd_index(limit);
+#else
+ pmdidx_limit = 0;
+#endif
+
+ for (pgdidx = 0; pgdidx <= pgdidx_limit; pgdidx++) {
+ pud_t *pud;
+
+ if (pgdidx >= hole_low && pgdidx < hole_high)
+ continue;
+
+ if (!pgd_val(pgd[pgdidx]))
+ continue;
+
+ pud = pud_offset(&pgd[pgdidx], 0);
+
+ if (PTRS_PER_PUD > 1) /* not folded */
+ flush |= (*func)(mm, virt_to_page(pud), PT_PUD);
+
+ for (pudidx = 0; pudidx < PTRS_PER_PUD; pudidx++) {
+ pmd_t *pmd;
+
+ if (pgdidx == pgdidx_limit &&
+ pudidx > pudidx_limit)
+ goto out;
+
+ if (pud_none(pud[pudidx]))
+ continue;
+
+ pmd = pmd_offset(&pud[pudidx], 0);
+
+ if (PTRS_PER_PMD > 1) /* not folded */
+ flush |= (*func)(mm, virt_to_page(pmd), PT_PMD);
+
+ for (pmdidx = 0; pmdidx < PTRS_PER_PMD; pmdidx++) {
+ struct page *pte;
+
+ if (pgdidx == pgdidx_limit &&
+ pudidx == pudidx_limit &&
+ pmdidx > pmdidx_limit)
+ goto out;
+
+ if (pmd_none(pmd[pmdidx]))
+ continue;
+
+ pte = pmd_page(pmd[pmdidx]);
+ flush |= (*func)(mm, pte, PT_PTE);
+ }
+ }
+ }
+
+out:
+ /* Do the top level last, so that the callbacks can use it as
+ a cue to do final things like tlb flushes. */
+ flush |= (*func)(mm, virt_to_page(pgd), PT_PGD);
+
+ return flush;
+}
+
+static int xen_pgd_walk(struct mm_struct *mm,
+ int (*func)(struct mm_struct *mm, struct page *,
+ enum pt_level),
+ unsigned long limit)
+{
+ return __xen_pgd_walk(mm, mm->pgd, func, limit);
+}
+
+/* If we're using split pte locks, then take the page's lock and
+ return a pointer to it. Otherwise return NULL. */
+static spinlock_t *xen_pte_lock(struct page *page, struct mm_struct *mm)
+{
+ spinlock_t *ptl = NULL;
+
+#if USE_SPLIT_PTLOCKS
+ ptl = __pte_lockptr(page);
+ spin_lock_nest_lock(ptl, &mm->page_table_lock);
+#endif
+
+ return ptl;
+}
+
+static void xen_pte_unlock(void *v)
+{
+ spinlock_t *ptl = v;
+ spin_unlock(ptl);
+}
+
+static void xen_do_pin(unsigned level, unsigned long pfn)
+{
+ struct mmuext_op op;
+
+ op.cmd = level;
+ op.arg1.mfn = pfn_to_mfn(pfn);
+
+ xen_extend_mmuext_op(&op);
+}
+
+static int xen_pin_page(struct mm_struct *mm, struct page *page,
+ enum pt_level level)
+{
+ unsigned pgfl = TestSetPagePinned(page);
+ int flush;
+
+ if (pgfl)
+ flush = 0; /* already pinned */
+ else if (PageHighMem(page))
+ /* kmaps need flushing if we found an unpinned
+ highpage */
+ flush = 1;
+ else {
+ void *pt = lowmem_page_address(page);
+ unsigned long pfn = page_to_pfn(page);
+ struct multicall_space mcs = __xen_mc_entry(0);
+ spinlock_t *ptl;
+
+ flush = 0;
+
+ /*
+ * We need to hold the pagetable lock between the time
+ * we make the pagetable RO and when we actually pin
+ * it. If we don't, then other users may come in and
+ * attempt to update the pagetable by writing it,
+ * which will fail because the memory is RO but not
+ * pinned, so Xen won't do the trap'n'emulate.
+ *
+ * If we're using split pte locks, we can't hold the
+ * entire pagetable's worth of locks during the
+ * traverse, because we may wrap the preempt count (8
+ * bits). The solution is to mark RO and pin each PTE
+ * page while holding the lock. This means the number
+ * of locks we end up holding is never more than a
+ * batch size (~32 entries, at present).
+ *
+ * If we're not using split pte locks, we needn't pin
+ * the PTE pages independently, because we're
+ * protected by the overall pagetable lock.
+ */
+ ptl = NULL;
+ if (level == PT_PTE)
+ ptl = xen_pte_lock(page, mm);
+
+ MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
+ pfn_pte(pfn, PAGE_KERNEL_RO),
+ level == PT_PGD ? UVMF_TLB_FLUSH : 0);
+
+ if (ptl) {
+ xen_do_pin(MMUEXT_PIN_L1_TABLE, pfn);
+
+ /* Queue a deferred unlock for when this batch
+ is completed. */
+ xen_mc_callback(xen_pte_unlock, ptl);
+ }
+ }
+
+ return flush;
+}
+
+/* This is called just after a mm has been created, but it has not
+ been used yet. We need to make sure that its pagetable is all
+ read-only, and can be pinned. */
+static void __xen_pgd_pin(struct mm_struct *mm, pgd_t *pgd)
+{
+ trace_xen_mmu_pgd_pin(mm, pgd);
+
+ xen_mc_batch();
+
+ if (__xen_pgd_walk(mm, pgd, xen_pin_page, USER_LIMIT)) {
+ /* re-enable interrupts for flushing */
+ xen_mc_issue(0);
+
+ kmap_flush_unused();
+
+ xen_mc_batch();
+ }
+
+#ifdef CONFIG_X86_64
+ {
+ pgd_t *user_pgd = xen_get_user_pgd(pgd);
+
+ xen_do_pin(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(pgd)));
+
+ if (user_pgd) {
+ xen_pin_page(mm, virt_to_page(user_pgd), PT_PGD);
+ xen_do_pin(MMUEXT_PIN_L4_TABLE,
+ PFN_DOWN(__pa(user_pgd)));
+ }
+ }
+#else /* CONFIG_X86_32 */
+#ifdef CONFIG_X86_PAE
+ /* Need to make sure unshared kernel PMD is pinnable */
+ xen_pin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
+ PT_PMD);
+#endif
+ xen_do_pin(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(pgd)));
+#endif /* CONFIG_X86_64 */
+ xen_mc_issue(0);
+}
+
+static void xen_pgd_pin(struct mm_struct *mm)
+{
+ __xen_pgd_pin(mm, mm->pgd);
+}
+
+/*
+ * On save, we need to pin all pagetables to make sure they get their
+ * mfns turned into pfns. Search the list for any unpinned pgds and pin
+ * them (unpinned pgds are not currently in use, probably because the
+ * process is under construction or destruction).
+ *
+ * Expected to be called in stop_machine() ("equivalent to taking
+ * every spinlock in the system"), so the locking doesn't really
+ * matter all that much.
+ */
+void xen_mm_pin_all(void)
+{
+ struct page *page;
+
+ spin_lock(&pgd_lock);
+
+ list_for_each_entry(page, &pgd_list, lru) {
+ if (!PagePinned(page)) {
+ __xen_pgd_pin(&init_mm, (pgd_t *)page_address(page));
+ SetPageSavePinned(page);
+ }
+ }
+
+ spin_unlock(&pgd_lock);
+}
+
+/*
+ * The init_mm pagetable is really pinned as soon as its created, but
+ * that's before we have page structures to store the bits. So do all
+ * the book-keeping now.
+ */
+static int __init xen_mark_pinned(struct mm_struct *mm, struct page *page,
+ enum pt_level level)
+{
+ SetPagePinned(page);
+ return 0;
+}
+
+static void __init xen_mark_init_mm_pinned(void)
+{
+ xen_pgd_walk(&init_mm, xen_mark_pinned, FIXADDR_TOP);
+}
+
+static int xen_unpin_page(struct mm_struct *mm, struct page *page,
+ enum pt_level level)
+{
+ unsigned pgfl = TestClearPagePinned(page);
+
+ if (pgfl && !PageHighMem(page)) {
+ void *pt = lowmem_page_address(page);
+ unsigned long pfn = page_to_pfn(page);
+ spinlock_t *ptl = NULL;
+ struct multicall_space mcs;
+
+ /*
+ * Do the converse to pin_page. If we're using split
+ * pte locks, we must be holding the lock for while
+ * the pte page is unpinned but still RO to prevent
+ * concurrent updates from seeing it in this
+ * partially-pinned state.
+ */
+ if (level == PT_PTE) {
+ ptl = xen_pte_lock(page, mm);
+
+ if (ptl)
+ xen_do_pin(MMUEXT_UNPIN_TABLE, pfn);
+ }
+
+ mcs = __xen_mc_entry(0);
+
+ MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
+ pfn_pte(pfn, PAGE_KERNEL),
+ level == PT_PGD ? UVMF_TLB_FLUSH : 0);
+
+ if (ptl) {
+ /* unlock when batch completed */
+ xen_mc_callback(xen_pte_unlock, ptl);
+ }
+ }
+
+ return 0; /* never need to flush on unpin */
+}
+
+/* Release a pagetables pages back as normal RW */
+static void __xen_pgd_unpin(struct mm_struct *mm, pgd_t *pgd)
+{
+ trace_xen_mmu_pgd_unpin(mm, pgd);
+
+ xen_mc_batch();
+
+ xen_do_pin(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
+
+#ifdef CONFIG_X86_64
+ {
+ pgd_t *user_pgd = xen_get_user_pgd(pgd);
+
+ if (user_pgd) {
+ xen_do_pin(MMUEXT_UNPIN_TABLE,
+ PFN_DOWN(__pa(user_pgd)));
+ xen_unpin_page(mm, virt_to_page(user_pgd), PT_PGD);
+ }
+ }
+#endif
+
+#ifdef CONFIG_X86_PAE
+ /* Need to make sure unshared kernel PMD is unpinned */
+ xen_unpin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
+ PT_PMD);
+#endif
+
+ __xen_pgd_walk(mm, pgd, xen_unpin_page, USER_LIMIT);
+
+ xen_mc_issue(0);
+}
+
+static void xen_pgd_unpin(struct mm_struct *mm)
+{
+ __xen_pgd_unpin(mm, mm->pgd);
+}
+
+/*
+ * On resume, undo any pinning done at save, so that the rest of the
+ * kernel doesn't see any unexpected pinned pagetables.
+ */
+void xen_mm_unpin_all(void)
+{
+ struct page *page;
+
+ spin_lock(&pgd_lock);
+
+ list_for_each_entry(page, &pgd_list, lru) {
+ if (PageSavePinned(page)) {
+ BUG_ON(!PagePinned(page));
+ __xen_pgd_unpin(&init_mm, (pgd_t *)page_address(page));
+ ClearPageSavePinned(page);
+ }
+ }
+
+ spin_unlock(&pgd_lock);
+}
+
+static void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
+{
+ spin_lock(&next->page_table_lock);
+ xen_pgd_pin(next);
+ spin_unlock(&next->page_table_lock);
+}
+
+static void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
+{
+ spin_lock(&mm->page_table_lock);
+ xen_pgd_pin(mm);
+ spin_unlock(&mm->page_table_lock);
+}
+
+
+#ifdef CONFIG_SMP
+/* Another cpu may still have their %cr3 pointing at the pagetable, so
+ we need to repoint it somewhere else before we can unpin it. */
+static void drop_other_mm_ref(void *info)
+{
+ struct mm_struct *mm = info;
+ struct mm_struct *active_mm;
+
+ active_mm = percpu_read(cpu_tlbstate.active_mm);
+
+ if (active_mm == mm && percpu_read(cpu_tlbstate.state) != TLBSTATE_OK)
+ leave_mm(smp_processor_id());
+
+ /* If this cpu still has a stale cr3 reference, then make sure
+ it has been flushed. */
+ if (percpu_read(xen_current_cr3) == __pa(mm->pgd))
+ load_cr3(swapper_pg_dir);
+}
+
+static void xen_drop_mm_ref(struct mm_struct *mm)
+{
+ cpumask_var_t mask;
+ unsigned cpu;
+
+ if (current->active_mm == mm) {
+ if (current->mm == mm)
+ load_cr3(swapper_pg_dir);
+ else
+ leave_mm(smp_processor_id());
+ }
+
+ /* Get the "official" set of cpus referring to our pagetable. */
+ if (!alloc_cpumask_var(&mask, GFP_ATOMIC)) {
+ for_each_online_cpu(cpu) {
+ if (!cpumask_test_cpu(cpu, mm_cpumask(mm))
+ && per_cpu(xen_current_cr3, cpu) != __pa(mm->pgd))
+ continue;
+ smp_call_function_single(cpu, drop_other_mm_ref, mm, 1);
+ }
+ return;
+ }
+ cpumask_copy(mask, mm_cpumask(mm));
+
+ /* It's possible that a vcpu may have a stale reference to our
+ cr3, because its in lazy mode, and it hasn't yet flushed
+ its set of pending hypercalls yet. In this case, we can
+ look at its actual current cr3 value, and force it to flush
+ if needed. */
+ for_each_online_cpu(cpu) {
+ if (per_cpu(xen_current_cr3, cpu) == __pa(mm->pgd))
+ cpumask_set_cpu(cpu, mask);
+ }
+
+ if (!cpumask_empty(mask))
+ smp_call_function_many(mask, drop_other_mm_ref, mm, 1);
+ free_cpumask_var(mask);
+}
+#else
+static void xen_drop_mm_ref(struct mm_struct *mm)
+{
+ if (current->active_mm == mm)
+ load_cr3(swapper_pg_dir);
+}
+#endif
+
+/*
+ * While a process runs, Xen pins its pagetables, which means that the
+ * hypervisor forces it to be read-only, and it controls all updates
+ * to it. This means that all pagetable updates have to go via the
+ * hypervisor, which is moderately expensive.
+ *
+ * Since we're pulling the pagetable down, we switch to use init_mm,
+ * unpin old process pagetable and mark it all read-write, which
+ * allows further operations on it to be simple memory accesses.
+ *
+ * The only subtle point is that another CPU may be still using the
+ * pagetable because of lazy tlb flushing. This means we need need to
+ * switch all CPUs off this pagetable before we can unpin it.
+ */
+static void xen_exit_mmap(struct mm_struct *mm)
+{
+ get_cpu(); /* make sure we don't move around */
+ xen_drop_mm_ref(mm);
+ put_cpu();
+
+ spin_lock(&mm->page_table_lock);
+
+ /* pgd may not be pinned in the error exit path of execve */
+ if (xen_page_pinned(mm->pgd))
+ xen_pgd_unpin(mm);
+
+ spin_unlock(&mm->page_table_lock);
+}
+
+static void __init xen_pagetable_setup_start(pgd_t *base)
+{
+}
+
+static __init void xen_mapping_pagetable_reserve(u64 start, u64 end)
+{
+ /* reserve the range used */
+ native_pagetable_reserve(start, end);
+
+ /* set as RW the rest */
+ printk(KERN_DEBUG "xen: setting RW the range %llx - %llx\n", end,
+ PFN_PHYS(pgt_buf_top));
+ while (end < PFN_PHYS(pgt_buf_top)) {
+ make_lowmem_page_readwrite(__va(end));
+ end += PAGE_SIZE;
+ }
+}
+
+static void xen_post_allocator_init(void);
+
+static void __init xen_pagetable_setup_done(pgd_t *base)
+{
+ xen_setup_shared_info();
+ xen_post_allocator_init();
+}
+
+static void xen_write_cr2(unsigned long cr2)
+{
+ percpu_read(xen_vcpu)->arch.cr2 = cr2;
+}
+
+static unsigned long xen_read_cr2(void)
+{
+ return percpu_read(xen_vcpu)->arch.cr2;
+}
+
+unsigned long xen_read_cr2_direct(void)
+{
+ return percpu_read(xen_vcpu_info.arch.cr2);
+}
+
+static void xen_flush_tlb(void)
+{
+ struct mmuext_op *op;
+ struct multicall_space mcs;
+
+ trace_xen_mmu_flush_tlb(0);
+
+ preempt_disable();
+
+ mcs = xen_mc_entry(sizeof(*op));
+
+ op = mcs.args;
+ op->cmd = MMUEXT_TLB_FLUSH_LOCAL;
+ MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+
+ preempt_enable();
+}
+
+static void xen_flush_tlb_single(unsigned long addr)
+{
+ struct mmuext_op *op;
+ struct multicall_space mcs;
+
+ trace_xen_mmu_flush_tlb_single(addr);
+
+ preempt_disable();
+
+ mcs = xen_mc_entry(sizeof(*op));
+ op = mcs.args;
+ op->cmd = MMUEXT_INVLPG_LOCAL;
+ op->arg1.linear_addr = addr & PAGE_MASK;
+ MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+
+ preempt_enable();
+}
+
+static void xen_flush_tlb_others(const struct cpumask *cpus,
+ struct mm_struct *mm, unsigned long va)
+{
+ struct {
+ struct mmuext_op op;
+#ifdef CONFIG_SMP
+ DECLARE_BITMAP(mask, num_processors);
+#else
+ DECLARE_BITMAP(mask, NR_CPUS);
+#endif
+ } *args;
+ struct multicall_space mcs;
+
+ trace_xen_mmu_flush_tlb_others(cpus, mm, va);
+
+ if (cpumask_empty(cpus))
+ return; /* nothing to do */
+
+ mcs = xen_mc_entry(sizeof(*args));
+ args = mcs.args;
+ args->op.arg2.vcpumask = to_cpumask(args->mask);
+
+ /* Remove us, and any offline CPUS. */
+ cpumask_and(to_cpumask(args->mask), cpus, cpu_online_mask);
+ cpumask_clear_cpu(smp_processor_id(), to_cpumask(args->mask));
+
+ if (va == TLB_FLUSH_ALL) {
+ args->op.cmd = MMUEXT_TLB_FLUSH_MULTI;
+ } else {
+ args->op.cmd = MMUEXT_INVLPG_MULTI;
+ args->op.arg1.linear_addr = va;
+ }
+
+ MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+}
+
+static unsigned long xen_read_cr3(void)
+{
+ return percpu_read(xen_cr3);
+}
+
+static void set_current_cr3(void *v)
+{
+ percpu_write(xen_current_cr3, (unsigned long)v);
+}
+
+static void __xen_write_cr3(bool kernel, unsigned long cr3)
+{
+ struct mmuext_op op;
+ unsigned long mfn;
+
+ trace_xen_mmu_write_cr3(kernel, cr3);
+
+ if (cr3)
+ mfn = pfn_to_mfn(PFN_DOWN(cr3));
+ else
+ mfn = 0;
+
+ WARN_ON(mfn == 0 && kernel);
+
+ op.cmd = kernel ? MMUEXT_NEW_BASEPTR : MMUEXT_NEW_USER_BASEPTR;
+ op.arg1.mfn = mfn;
+
+ xen_extend_mmuext_op(&op);
+
+ if (kernel) {
+ percpu_write(xen_cr3, cr3);
+
+ /* Update xen_current_cr3 once the batch has actually
+ been submitted. */
+ xen_mc_callback(set_current_cr3, (void *)cr3);
+ }
+}
+
+static void xen_write_cr3(unsigned long cr3)
+{
+ BUG_ON(preemptible());
+
+ xen_mc_batch(); /* disables interrupts */
+
+ /* Update while interrupts are disabled, so its atomic with
+ respect to ipis */
+ percpu_write(xen_cr3, cr3);
+
+ __xen_write_cr3(true, cr3);
+
+#ifdef CONFIG_X86_64
+ {
+ pgd_t *user_pgd = xen_get_user_pgd(__va(cr3));
+ if (user_pgd)
+ __xen_write_cr3(false, __pa(user_pgd));
+ else
+ __xen_write_cr3(false, 0);
+ }
+#endif
+
+ xen_mc_issue(PARAVIRT_LAZY_CPU); /* interrupts restored */
+}
+
+static int xen_pgd_alloc(struct mm_struct *mm)
+{
+ pgd_t *pgd = mm->pgd;
+ int ret = 0;
+
+ BUG_ON(PagePinned(virt_to_page(pgd)));
+
+#ifdef CONFIG_X86_64
+ {
+ struct page *page = virt_to_page(pgd);
+ pgd_t *user_pgd;
+
+ BUG_ON(page->private != 0);
+
+ ret = -ENOMEM;
+
+ user_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+ page->private = (unsigned long)user_pgd;
+
+ if (user_pgd != NULL) {
+ user_pgd[pgd_index(VSYSCALL_START)] =
+ __pgd(__pa(level3_user_vsyscall) | _PAGE_TABLE);
+ ret = 0;
+ }
+
+ BUG_ON(PagePinned(virt_to_page(xen_get_user_pgd(pgd))));
+ }
+#endif
+
+ return ret;
+}
+
+static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
+{
+#ifdef CONFIG_X86_64
+ pgd_t *user_pgd = xen_get_user_pgd(pgd);
+
+ if (user_pgd)
+ free_page((unsigned long)user_pgd);
+#endif
+}
+
+#ifdef CONFIG_X86_32
+static pte_t __init mask_rw_pte(pte_t *ptep, pte_t pte)
+{
+ /* If there's an existing pte, then don't allow _PAGE_RW to be set */
+ if (pte_val_ma(*ptep) & _PAGE_PRESENT)
+ pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) &
+ pte_val_ma(pte));
+
+ return pte;
+}
+#else /* CONFIG_X86_64 */
+static pte_t __init mask_rw_pte(pte_t *ptep, pte_t pte)
+{
+ unsigned long pfn = pte_pfn(pte);
+
+ /*
+ * If the new pfn is within the range of the newly allocated
+ * kernel pagetable, and it isn't being mapped into an
+ * early_ioremap fixmap slot as a freshly allocated page, make sure
+ * it is RO.
+ */
+ if (((!is_early_ioremap_ptep(ptep) &&
+ pfn >= pgt_buf_start && pfn < pgt_buf_top)) ||
+ (is_early_ioremap_ptep(ptep) && pfn != (pgt_buf_end - 1)))
+ pte = pte_wrprotect(pte);
+
+ return pte;
+}
+#endif /* CONFIG_X86_64 */
+
+/* Init-time set_pte while constructing initial pagetables, which
+ doesn't allow RO pagetable pages to be remapped RW */
+static void __init xen_set_pte_init(pte_t *ptep, pte_t pte)
+{
+ pte = mask_rw_pte(ptep, pte);
+
+ xen_set_pte(ptep, pte);
+}
+
+static void pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
+{
+ struct mmuext_op op;
+ op.cmd = cmd;
+ op.arg1.mfn = pfn_to_mfn(pfn);
+ if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
+ BUG();
+}
+
+/* Early in boot, while setting up the initial pagetable, assume
+ everything is pinned. */
+static void __init xen_alloc_pte_init(struct mm_struct *mm, unsigned long pfn)
+{
+#ifdef CONFIG_FLATMEM
+ BUG_ON(mem_map); /* should only be used early */
+#endif
+ make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
+ pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
+}
+
+/* Used for pmd and pud */
+static void __init xen_alloc_pmd_init(struct mm_struct *mm, unsigned long pfn)
+{
+#ifdef CONFIG_FLATMEM
+ BUG_ON(mem_map); /* should only be used early */
+#endif
+ make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
+}
+
+/* Early release_pte assumes that all pts are pinned, since there's
+ only init_mm and anything attached to that is pinned. */
+static void __init xen_release_pte_init(unsigned long pfn)
+{
+ pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
+ make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
+}
+
+static void __init xen_release_pmd_init(unsigned long pfn)
+{
+ make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
+}
+
+static inline void __pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
+{
+ struct multicall_space mcs;
+ struct mmuext_op *op;
+
+ mcs = __xen_mc_entry(sizeof(*op));
+ op = mcs.args;
+ op->cmd = cmd;
+ op->arg1.mfn = pfn_to_mfn(pfn);
+
+ MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
+}
+
+static inline void __set_pfn_prot(unsigned long pfn, pgprot_t prot)
+{
+ struct multicall_space mcs;
+ unsigned long addr = (unsigned long)__va(pfn << PAGE_SHIFT);
+
+ mcs = __xen_mc_entry(0);
+ MULTI_update_va_mapping(mcs.mc, (unsigned long)addr,
+ pfn_pte(pfn, prot), 0);
+}
+
+/* This needs to make sure the new pte page is pinned iff its being
+ attached to a pinned pagetable. */
+static inline void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn,
+ unsigned level)
+{
+ bool pinned = PagePinned(virt_to_page(mm->pgd));
+
+ trace_xen_mmu_alloc_ptpage(mm, pfn, level, pinned);
+
+ if (pinned) {
+ struct page *page = pfn_to_page(pfn);
+
+ SetPagePinned(page);
+
+ if (!PageHighMem(page)) {
+ xen_mc_batch();
+
+ __set_pfn_prot(pfn, PAGE_KERNEL_RO);
+
+ if (level == PT_PTE && USE_SPLIT_PTLOCKS)
+ __pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+ } else {
+ /* make sure there are no stray mappings of
+ this page */
+ kmap_flush_unused();
+ }
+ }
+}
+
+static void xen_alloc_pte(struct mm_struct *mm, unsigned long pfn)
+{
+ xen_alloc_ptpage(mm, pfn, PT_PTE);
+}
+
+static void xen_alloc_pmd(struct mm_struct *mm, unsigned long pfn)
+{
+ xen_alloc_ptpage(mm, pfn, PT_PMD);
+}
+
+/* This should never happen until we're OK to use struct page */
+static inline void xen_release_ptpage(unsigned long pfn, unsigned level)
+{
+ struct page *page = pfn_to_page(pfn);
+ bool pinned = PagePinned(page);
+
+ trace_xen_mmu_release_ptpage(pfn, level, pinned);
+
+ if (pinned) {
+ if (!PageHighMem(page)) {
+ xen_mc_batch();
+
+ if (level == PT_PTE && USE_SPLIT_PTLOCKS)
+ __pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
+
+ __set_pfn_prot(pfn, PAGE_KERNEL);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+ }
+ ClearPagePinned(page);
+ }
+}
+
+static void xen_release_pte(unsigned long pfn)
+{
+ xen_release_ptpage(pfn, PT_PTE);
+}
+
+static void xen_release_pmd(unsigned long pfn)
+{
+ xen_release_ptpage(pfn, PT_PMD);
+}
+
+#if PAGETABLE_LEVELS == 4
+static void xen_alloc_pud(struct mm_struct *mm, unsigned long pfn)
+{
+ xen_alloc_ptpage(mm, pfn, PT_PUD);
+}
+
+static void xen_release_pud(unsigned long pfn)
+{
+ xen_release_ptpage(pfn, PT_PUD);
+}
+#endif
+
+void __init xen_reserve_top(void)
+{
+#ifdef CONFIG_X86_32
+ unsigned long top = HYPERVISOR_VIRT_START;
+ struct xen_platform_parameters pp;
+
+ if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0)
+ top = pp.virt_start;
+
+ reserve_top_address(-top);
+#endif /* CONFIG_X86_32 */
+}
+
+/*
+ * Like __va(), but returns address in the kernel mapping (which is
+ * all we have until the physical memory mapping has been set up.
+ */
+static void *__ka(phys_addr_t paddr)
+{
+#ifdef CONFIG_X86_64
+ return (void *)(paddr + __START_KERNEL_map);
+#else
+ return __va(paddr);
+#endif
+}
+
+/* Convert a machine address to physical address */
+static unsigned long m2p(phys_addr_t maddr)
+{
+ phys_addr_t paddr;
+
+ maddr &= PTE_PFN_MASK;
+ paddr = mfn_to_pfn(maddr >> PAGE_SHIFT) << PAGE_SHIFT;
+
+ return paddr;
+}
+
+/* Convert a machine address to kernel virtual */
+static void *m2v(phys_addr_t maddr)
+{
+ return __ka(m2p(maddr));
+}
+
+/* Set the page permissions on an identity-mapped pages */
+static void set_page_prot(void *addr, pgprot_t prot)
+{
+ unsigned long pfn = __pa(addr) >> PAGE_SHIFT;
+ pte_t pte = pfn_pte(pfn, prot);
+
+ if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, 0))
+ BUG();
+}
+
+static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
+{
+ unsigned pmdidx, pteidx;
+ unsigned ident_pte;
+ unsigned long pfn;
+
+ level1_ident_pgt = extend_brk(sizeof(pte_t) * LEVEL1_IDENT_ENTRIES,
+ PAGE_SIZE);
+
+ ident_pte = 0;
+ pfn = 0;
+ for (pmdidx = 0; pmdidx < PTRS_PER_PMD && pfn < max_pfn; pmdidx++) {
+ pte_t *pte_page;
+
+ /* Reuse or allocate a page of ptes */
+ if (pmd_present(pmd[pmdidx]))
+ pte_page = m2v(pmd[pmdidx].pmd);
+ else {
+ /* Check for free pte pages */
+ if (ident_pte == LEVEL1_IDENT_ENTRIES)
+ break;
+
+ pte_page = &level1_ident_pgt[ident_pte];
+ ident_pte += PTRS_PER_PTE;
+
+ pmd[pmdidx] = __pmd(__pa(pte_page) | _PAGE_TABLE);
+ }
+
+ /* Install mappings */
+ for (pteidx = 0; pteidx < PTRS_PER_PTE; pteidx++, pfn++) {
+ pte_t pte;
+
+#ifdef CONFIG_X86_32
+ if (pfn > max_pfn_mapped)
+ max_pfn_mapped = pfn;
+#endif
+
+ if (!pte_none(pte_page[pteidx]))
+ continue;
+
+ pte = pfn_pte(pfn, PAGE_KERNEL_EXEC);
+ pte_page[pteidx] = pte;
+ }
+ }
+
+ for (pteidx = 0; pteidx < ident_pte; pteidx += PTRS_PER_PTE)
+ set_page_prot(&level1_ident_pgt[pteidx], PAGE_KERNEL_RO);
+
+ set_page_prot(pmd, PAGE_KERNEL_RO);
+}
+
+void __init xen_setup_machphys_mapping(void)
+{
+ struct xen_machphys_mapping mapping;
+
+ if (HYPERVISOR_memory_op(XENMEM_machphys_mapping, &mapping) == 0) {
+ machine_to_phys_mapping = (unsigned long *)mapping.v_start;
+ machine_to_phys_nr = mapping.max_mfn + 1;
+ } else {
+ machine_to_phys_nr = MACH2PHYS_NR_ENTRIES;
+ }
+#ifdef CONFIG_X86_32
+ WARN_ON((machine_to_phys_mapping + (machine_to_phys_nr - 1))
+ < machine_to_phys_mapping);
+#endif
+}
+
+#ifdef CONFIG_X86_64
+static void convert_pfn_mfn(void *v)
+{
+ pte_t *pte = v;
+ int i;
+
+ /* All levels are converted the same way, so just treat them
+ as ptes. */
+ for (i = 0; i < PTRS_PER_PTE; i++)
+ pte[i] = xen_make_pte(pte[i].pte);
+}
+
+/*
+ * Set up the initial kernel pagetable.
+ *
+ * We can construct this by grafting the Xen provided pagetable into
+ * head_64.S's preconstructed pagetables. We copy the Xen L2's into
+ * level2_ident_pgt, level2_kernel_pgt and level2_fixmap_pgt. This
+ * means that only the kernel has a physical mapping to start with -
+ * but that's enough to get __va working. We need to fill in the rest
+ * of the physical mapping once some sort of allocator has been set
+ * up.
+ */
+pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd,
+ unsigned long max_pfn)
+{
+ pud_t *l3;
+ pmd_t *l2;
+
+ /* max_pfn_mapped is the last pfn mapped in the initial memory
+ * mappings. Considering that on Xen after the kernel mappings we
+ * have the mappings of some pages that don't exist in pfn space, we
+ * set max_pfn_mapped to the last real pfn mapped. */
+ max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));
+
+ /* Zap identity mapping */
+ init_level4_pgt[0] = __pgd(0);
+
+ /* Pre-constructed entries are in pfn, so convert to mfn */
+ convert_pfn_mfn(init_level4_pgt);
+ convert_pfn_mfn(level3_ident_pgt);
+ convert_pfn_mfn(level3_kernel_pgt);
+
+ l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd);
+ l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud);
+
+ memcpy(level2_ident_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);
+ memcpy(level2_kernel_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);
+
+ l3 = m2v(pgd[pgd_index(__START_KERNEL_map + PMD_SIZE)].pgd);
+ l2 = m2v(l3[pud_index(__START_KERNEL_map + PMD_SIZE)].pud);
+ memcpy(level2_fixmap_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);
+
+ /* Set up identity map */
+ xen_map_identity_early(level2_ident_pgt, max_pfn);
+
+ /* Make pagetable pieces RO */
+ set_page_prot(init_level4_pgt, PAGE_KERNEL_RO);
+ set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO);
+ set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO);
+ set_page_prot(level3_user_vsyscall, PAGE_KERNEL_RO);
+ set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
+ set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO);
+
+ /* Pin down new L4 */
+ pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE,
+ PFN_DOWN(__pa_symbol(init_level4_pgt)));
+
+ /* Unpin Xen-provided one */
+ pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
+
+ /* Switch over */
+ pgd = init_level4_pgt;
+
+ /*
+ * At this stage there can be no user pgd, and no page
+ * structure to attach it to, so make sure we just set kernel
+ * pgd.
+ */
+ xen_mc_batch();
+ __xen_write_cr3(true, __pa(pgd));
+ xen_mc_issue(PARAVIRT_LAZY_CPU);
+
+ memblock_reserve(__pa(xen_start_info->pt_base),
+ xen_start_info->nr_pt_frames * PAGE_SIZE);
+
+ return pgd;
+}
+#else /* !CONFIG_X86_64 */
+static RESERVE_BRK_ARRAY(pmd_t, initial_kernel_pmd, PTRS_PER_PMD);
+static RESERVE_BRK_ARRAY(pmd_t, swapper_kernel_pmd, PTRS_PER_PMD);
+
+static void __init xen_write_cr3_init(unsigned long cr3)
+{
+ unsigned long pfn = PFN_DOWN(__pa(swapper_pg_dir));
+
+ BUG_ON(read_cr3() != __pa(initial_page_table));
+ BUG_ON(cr3 != __pa(swapper_pg_dir));
+
+ /*
+ * We are switching to swapper_pg_dir for the first time (from
+ * initial_page_table) and therefore need to mark that page
+ * read-only and then pin it.
+ *
+ * Xen disallows sharing of kernel PMDs for PAE
+ * guests. Therefore we must copy the kernel PMD from
+ * initial_page_table into a new kernel PMD to be used in
+ * swapper_pg_dir.
+ */
+ swapper_kernel_pmd =
+ extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
+ memcpy(swapper_kernel_pmd, initial_kernel_pmd,
+ sizeof(pmd_t) * PTRS_PER_PMD);
+ swapper_pg_dir[KERNEL_PGD_BOUNDARY] =
+ __pgd(__pa(swapper_kernel_pmd) | _PAGE_PRESENT);
+ set_page_prot(swapper_kernel_pmd, PAGE_KERNEL_RO);
+
+ set_page_prot(swapper_pg_dir, PAGE_KERNEL_RO);
+ xen_write_cr3(cr3);
+ pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, pfn);
+
+ pin_pagetable_pfn(MMUEXT_UNPIN_TABLE,
+ PFN_DOWN(__pa(initial_page_table)));
+ set_page_prot(initial_page_table, PAGE_KERNEL);
+ set_page_prot(initial_kernel_pmd, PAGE_KERNEL);
+
+ pv_mmu_ops.write_cr3 = &xen_write_cr3;
+}
+
+pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd,
+ unsigned long max_pfn)
+{
+ pmd_t *kernel_pmd;
+
+ initial_kernel_pmd =
+ extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
+
+ max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->pt_base) +
+ xen_start_info->nr_pt_frames * PAGE_SIZE +
+ 512*1024);
+
+ kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
+ memcpy(initial_kernel_pmd, kernel_pmd, sizeof(pmd_t) * PTRS_PER_PMD);
+
+ xen_map_identity_early(initial_kernel_pmd, max_pfn);
+
+ memcpy(initial_page_table, pgd, sizeof(pgd_t) * PTRS_PER_PGD);
+ initial_page_table[KERNEL_PGD_BOUNDARY] =
+ __pgd(__pa(initial_kernel_pmd) | _PAGE_PRESENT);
+
+ set_page_prot(initial_kernel_pmd, PAGE_KERNEL_RO);
+ set_page_prot(initial_page_table, PAGE_KERNEL_RO);
+ set_page_prot(empty_zero_page, PAGE_KERNEL_RO);
+
+ pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
+
+ pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE,
+ PFN_DOWN(__pa(initial_page_table)));
+ xen_write_cr3(__pa(initial_page_table));
+
+ memblock_reserve(__pa(xen_start_info->pt_base),
+ xen_start_info->nr_pt_frames * PAGE_SIZE);
+
+ return initial_page_table;
+}
+#endif /* CONFIG_X86_64 */
+
+static unsigned char dummy_mapping[PAGE_SIZE] __page_aligned_bss;
+
+static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
+{
+ pte_t pte;
+
+ phys >>= PAGE_SHIFT;
+
+ switch (idx) {
+ case FIX_BTMAP_END ... FIX_BTMAP_BEGIN:
+#ifdef CONFIG_X86_F00F_BUG
+ case FIX_F00F_IDT:
+#endif
+#ifdef CONFIG_X86_32
+ case FIX_WP_TEST:
+ case FIX_VDSO:
+# ifdef CONFIG_HIGHMEM
+ case FIX_KMAP_BEGIN ... FIX_KMAP_END:
+# endif
+#else
+ case VSYSCALL_LAST_PAGE ... VSYSCALL_FIRST_PAGE:
+ case VVAR_PAGE:
+#endif
+ case FIX_TEXT_POKE0:
+ case FIX_TEXT_POKE1:
+ /* All local page mappings */
+ pte = pfn_pte(phys, prot);
+ break;
+
+#ifdef CONFIG_X86_LOCAL_APIC
+ case FIX_APIC_BASE: /* maps dummy local APIC */
+ pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
+ break;
+#endif
+
+#ifdef CONFIG_X86_IO_APIC
+ case FIX_IO_APIC_BASE_0 ... FIX_IO_APIC_BASE_END:
+ /*
+ * We just don't map the IO APIC - all access is via
+ * hypercalls. Keep the address in the pte for reference.
+ */
+ pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
+ break;
+#endif
+
+ case FIX_PARAVIRT_BOOTMAP:
+ /* This is an MFN, but it isn't an IO mapping from the
+ IO domain */
+ pte = mfn_pte(phys, prot);
+ break;
+
+ default:
+ /* By default, set_fixmap is used for hardware mappings */
+ pte = mfn_pte(phys, __pgprot(pgprot_val(prot) | _PAGE_IOMAP));
+ break;
+ }
+
+ __native_set_fixmap(idx, pte);
+
+#ifdef CONFIG_X86_64
+ /* Replicate changes to map the vsyscall page into the user
+ pagetable vsyscall mapping. */
+ if ((idx >= VSYSCALL_LAST_PAGE && idx <= VSYSCALL_FIRST_PAGE) ||
+ idx == VVAR_PAGE) {
+ unsigned long vaddr = __fix_to_virt(idx);
+ set_pte_vaddr_pud(level3_user_vsyscall, vaddr, pte);
+ }
+#endif
+}
+
+void __init xen_ident_map_ISA(void)
+{
+ unsigned long pa;
+
+ /*
+ * If we're dom0, then linear map the ISA machine addresses into
+ * the kernel's address space.
+ */
+ if (!xen_initial_domain())
+ return;
+
+ xen_raw_printk("Xen: setup ISA identity maps\n");
+
+ for (pa = ISA_START_ADDRESS; pa < ISA_END_ADDRESS; pa += PAGE_SIZE) {
+ pte_t pte = mfn_pte(PFN_DOWN(pa), PAGE_KERNEL_IO);
+
+ if (HYPERVISOR_update_va_mapping(PAGE_OFFSET + pa, pte, 0))
+ BUG();
+ }
+
+ xen_flush_tlb();
+}
+
+static void __init xen_post_allocator_init(void)
+{
+ pv_mmu_ops.set_pte = xen_set_pte;
+ pv_mmu_ops.set_pmd = xen_set_pmd;
+ pv_mmu_ops.set_pud = xen_set_pud;
+#if PAGETABLE_LEVELS == 4
+ pv_mmu_ops.set_pgd = xen_set_pgd;
+#endif
+
+ /* This will work as long as patching hasn't happened yet
+ (which it hasn't) */
+ pv_mmu_ops.alloc_pte = xen_alloc_pte;
+ pv_mmu_ops.alloc_pmd = xen_alloc_pmd;
+ pv_mmu_ops.release_pte = xen_release_pte;
+ pv_mmu_ops.release_pmd = xen_release_pmd;
+#if PAGETABLE_LEVELS == 4
+ pv_mmu_ops.alloc_pud = xen_alloc_pud;
+ pv_mmu_ops.release_pud = xen_release_pud;
+#endif
+
+#ifdef CONFIG_X86_64
+ SetPagePinned(virt_to_page(level3_user_vsyscall));
+#endif
+ xen_mark_init_mm_pinned();
+}
+
+static void xen_leave_lazy_mmu(void)
+{
+ preempt_disable();
+ xen_mc_flush();
+ paravirt_leave_lazy_mmu();
+ preempt_enable();
+}
+
+static const struct pv_mmu_ops xen_mmu_ops __initconst = {
+ .read_cr2 = xen_read_cr2,
+ .write_cr2 = xen_write_cr2,
+
+ .read_cr3 = xen_read_cr3,
+#ifdef CONFIG_X86_32
+ .write_cr3 = xen_write_cr3_init,
+#else
+ .write_cr3 = xen_write_cr3,
+#endif
+
+ .flush_tlb_user = xen_flush_tlb,
+ .flush_tlb_kernel = xen_flush_tlb,
+ .flush_tlb_single = xen_flush_tlb_single,
+ .flush_tlb_others = xen_flush_tlb_others,
+
+ .pte_update = paravirt_nop,
+ .pte_update_defer = paravirt_nop,
+
+ .pgd_alloc = xen_pgd_alloc,
+ .pgd_free = xen_pgd_free,
+
+ .alloc_pte = xen_alloc_pte_init,
+ .release_pte = xen_release_pte_init,
+ .alloc_pmd = xen_alloc_pmd_init,
+ .release_pmd = xen_release_pmd_init,
+
+ .set_pte = xen_set_pte_init,
+ .set_pte_at = xen_set_pte_at,
+ .set_pmd = xen_set_pmd_hyper,
+
+ .ptep_modify_prot_start = __ptep_modify_prot_start,
+ .ptep_modify_prot_commit = __ptep_modify_prot_commit,
+
+ .pte_val = PV_CALLEE_SAVE(xen_pte_val),
+ .pgd_val = PV_CALLEE_SAVE(xen_pgd_val),
+
+ .make_pte = PV_CALLEE_SAVE(xen_make_pte),
+ .make_pgd = PV_CALLEE_SAVE(xen_make_pgd),
+
+#ifdef CONFIG_X86_PAE
+ .set_pte_atomic = xen_set_pte_atomic,
+ .pte_clear = xen_pte_clear,
+ .pmd_clear = xen_pmd_clear,
+#endif /* CONFIG_X86_PAE */
+ .set_pud = xen_set_pud_hyper,
+
+ .make_pmd = PV_CALLEE_SAVE(xen_make_pmd),
+ .pmd_val = PV_CALLEE_SAVE(xen_pmd_val),
+
+#if PAGETABLE_LEVELS == 4
+ .pud_val = PV_CALLEE_SAVE(xen_pud_val),
+ .make_pud = PV_CALLEE_SAVE(xen_make_pud),
+ .set_pgd = xen_set_pgd_hyper,
+
+ .alloc_pud = xen_alloc_pmd_init,
+ .release_pud = xen_release_pmd_init,
+#endif /* PAGETABLE_LEVELS == 4 */
+
+ .activate_mm = xen_activate_mm,
+ .dup_mmap = xen_dup_mmap,
+ .exit_mmap = xen_exit_mmap,
+
+ .lazy_mode = {
+ .enter = paravirt_enter_lazy_mmu,
+ .leave = xen_leave_lazy_mmu,
+ },
+
+ .set_fixmap = xen_set_fixmap,
+};
+
+void __init xen_init_mmu_ops(void)
+{
+ x86_init.mapping.pagetable_reserve = xen_mapping_pagetable_reserve;
+ x86_init.paging.pagetable_setup_start = xen_pagetable_setup_start;
+ x86_init.paging.pagetable_setup_done = xen_pagetable_setup_done;
+ pv_mmu_ops = xen_mmu_ops;
+
+ memset(dummy_mapping, 0xff, PAGE_SIZE);
+}
+
+/* Protected by xen_reservation_lock. */
+#define MAX_CONTIG_ORDER 9 /* 2MB */
+static unsigned long discontig_frames[1<<MAX_CONTIG_ORDER];
+
+#define VOID_PTE (mfn_pte(0, __pgprot(0)))
+static void xen_zap_pfn_range(unsigned long vaddr, unsigned int order,
+ unsigned long *in_frames,
+ unsigned long *out_frames)
+{
+ int i;
+ struct multicall_space mcs;
+
+ xen_mc_batch();
+ for (i = 0; i < (1UL<<order); i++, vaddr += PAGE_SIZE) {
+ mcs = __xen_mc_entry(0);
+
+ if (in_frames)
+ in_frames[i] = virt_to_mfn(vaddr);
+
+ MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0);
+ __set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);
+
+ if (out_frames)
+ out_frames[i] = virt_to_pfn(vaddr);
+ }
+ xen_mc_issue(0);
+}
+
+/*
+ * Update the pfn-to-mfn mappings for a virtual address range, either to
+ * point to an array of mfns, or contiguously from a single starting
+ * mfn.
+ */
+static void xen_remap_exchanged_ptes(unsigned long vaddr, int order,
+ unsigned long *mfns,
+ unsigned long first_mfn)
+{
+ unsigned i, limit;
+ unsigned long mfn;
+
+ xen_mc_batch();
+
+ limit = 1u << order;
+ for (i = 0; i < limit; i++, vaddr += PAGE_SIZE) {
+ struct multicall_space mcs;
+ unsigned flags;
+
+ mcs = __xen_mc_entry(0);
+ if (mfns)
+ mfn = mfns[i];
+ else
+ mfn = first_mfn + i;
+
+ if (i < (limit - 1))
+ flags = 0;
+ else {
+ if (order == 0)
+ flags = UVMF_INVLPG | UVMF_ALL;
+ else
+ flags = UVMF_TLB_FLUSH | UVMF_ALL;
+ }
+
+ MULTI_update_va_mapping(mcs.mc, vaddr,
+ mfn_pte(mfn, PAGE_KERNEL), flags);
+
+ set_phys_to_machine(virt_to_pfn(vaddr), mfn);
+ }
+
+ xen_mc_issue(0);
+}
+
+/*
+ * Perform the hypercall to exchange a region of our pfns to point to
+ * memory with the required contiguous alignment. Takes the pfns as
+ * input, and populates mfns as output.
+ *
+ * Returns a success code indicating whether the hypervisor was able to
+ * satisfy the request or not.
+ */
+static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in,
+ unsigned long *pfns_in,
+ unsigned long extents_out,
+ unsigned int order_out,
+ unsigned long *mfns_out,
+ unsigned int address_bits)
+{
+ long rc;
+ int success;
+
+ struct xen_memory_exchange exchange = {
+ .in = {
+ .nr_extents = extents_in,
+ .extent_order = order_in,
+ .extent_start = pfns_in,
+ .domid = DOMID_SELF
+ },
+ .out = {
+ .nr_extents = extents_out,
+ .extent_order = order_out,
+ .extent_start = mfns_out,
+ .address_bits = address_bits,
+ .domid = DOMID_SELF
+ }
+ };
+
+ BUG_ON(extents_in << order_in != extents_out << order_out);
+
+ rc = HYPERVISOR_memory_op(XENMEM_exchange, &exchange);
+ success = (exchange.nr_exchanged == extents_in);
+
+ BUG_ON(!success && ((exchange.nr_exchanged != 0) || (rc == 0)));
+ BUG_ON(success && (rc != 0));
+
+ return success;
+}
+
+int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
+ unsigned int address_bits)
+{
+ unsigned long *in_frames = discontig_frames, out_frame;
+ unsigned long flags;
+ int success;
+
+ /*
+ * Currently an auto-translated guest will not perform I/O, nor will
+ * it require PAE page directories below 4GB. Therefore any calls to
+ * this function are redundant and can be ignored.
+ */
+
+ if (xen_feature(XENFEAT_auto_translated_physmap))
+ return 0;
+
+ if (unlikely(order > MAX_CONTIG_ORDER))
+ return -ENOMEM;
+
+ memset((void *) vstart, 0, PAGE_SIZE << order);
+
+ spin_lock_irqsave(&xen_reservation_lock, flags);
+
+ /* 1. Zap current PTEs, remembering MFNs. */
+ xen_zap_pfn_range(vstart, order, in_frames, NULL);
+
+ /* 2. Get a new contiguous memory extent. */
+ out_frame = virt_to_pfn(vstart);
+ success = xen_exchange_memory(1UL << order, 0, in_frames,
+ 1, order, &out_frame,
+ address_bits);
+
+ /* 3. Map the new extent in place of old pages. */
+ if (success)
+ xen_remap_exchanged_ptes(vstart, order, NULL, out_frame);
+ else
+ xen_remap_exchanged_ptes(vstart, order, in_frames, 0);
+
+ spin_unlock_irqrestore(&xen_reservation_lock, flags);
+
+ return success ? 0 : -ENOMEM;
+}
+EXPORT_SYMBOL_GPL(xen_create_contiguous_region);
+
+void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order)
+{
+ unsigned long *out_frames = discontig_frames, in_frame;
+ unsigned long flags;
+ int success;
+
+ if (xen_feature(XENFEAT_auto_translated_physmap))
+ return;
+
+ if (unlikely(order > MAX_CONTIG_ORDER))
+ return;
+
+ memset((void *) vstart, 0, PAGE_SIZE << order);
+
+ spin_lock_irqsave(&xen_reservation_lock, flags);
+
+ /* 1. Find start MFN of contiguous extent. */
+ in_frame = virt_to_mfn(vstart);
+
+ /* 2. Zap current PTEs. */
+ xen_zap_pfn_range(vstart, order, NULL, out_frames);
+
+ /* 3. Do the exchange for non-contiguous MFNs. */
+ success = xen_exchange_memory(1, order, &in_frame, 1UL << order,
+ 0, out_frames, 0);
+
+ /* 4. Map new pages in place of old pages. */
+ if (success)
+ xen_remap_exchanged_ptes(vstart, order, out_frames, 0);
+ else
+ xen_remap_exchanged_ptes(vstart, order, NULL, in_frame);
+
+ spin_unlock_irqrestore(&xen_reservation_lock, flags);
+}
+EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
+
+#ifdef CONFIG_XEN_PVHVM
+static void xen_hvm_exit_mmap(struct mm_struct *mm)
+{
+ struct xen_hvm_pagetable_dying a;
+ int rc;
+
+ a.domid = DOMID_SELF;
+ a.gpa = __pa(mm->pgd);
+ rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a);
+ WARN_ON_ONCE(rc < 0);
+}
+
+static int is_pagetable_dying_supported(void)
+{
+ struct xen_hvm_pagetable_dying a;
+ int rc = 0;
+
+ a.domid = DOMID_SELF;
+ a.gpa = 0x00;
+ rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a);
+ if (rc < 0) {
+ printk(KERN_DEBUG "HVMOP_pagetable_dying not supported\n");
+ return 0;
+ }
+ return 1;
+}
+
+void __init xen_hvm_init_mmu_ops(void)
+{
+ if (is_pagetable_dying_supported())
+ pv_mmu_ops.exit_mmap = xen_hvm_exit_mmap;
+}
+#endif
+
+#define REMAP_BATCH_SIZE 16
+
+struct remap_data {
+ unsigned long mfn;
+ pgprot_t prot;
+ struct mmu_update *mmu_update;
+};
+
+static int remap_area_mfn_pte_fn(pte_t *ptep, pgtable_t token,
+ unsigned long addr, void *data)
+{
+ struct remap_data *rmd = data;
+ pte_t pte = pte_mkspecial(pfn_pte(rmd->mfn++, rmd->prot));
+
+ rmd->mmu_update->ptr = virt_to_machine(ptep).maddr;
+ rmd->mmu_update->val = pte_val_ma(pte);
+ rmd->mmu_update++;
+
+ return 0;
+}
+
+int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
+ unsigned long addr,
+ unsigned long mfn, int nr,
+ pgprot_t prot, unsigned domid)
+{
+ struct remap_data rmd;
+ struct mmu_update mmu_update[REMAP_BATCH_SIZE];
+ int batch;
+ unsigned long range;
+ int err = 0;
+
+ prot = __pgprot(pgprot_val(prot) | _PAGE_IOMAP);
+
+ BUG_ON(!((vma->vm_flags & (VM_PFNMAP | VM_RESERVED | VM_IO)) ==
+ (VM_PFNMAP | VM_RESERVED | VM_IO)));
+
+ rmd.mfn = mfn;
+ rmd.prot = prot;
+
+ while (nr) {
+ batch = min(REMAP_BATCH_SIZE, nr);
+ range = (unsigned long)batch << PAGE_SHIFT;
+
+ rmd.mmu_update = mmu_update;
+ err = apply_to_page_range(vma->vm_mm, addr, range,
+ remap_area_mfn_pte_fn, &rmd);
+ if (err)
+ goto out;
+
+ err = -EFAULT;
+ if (HYPERVISOR_mmu_update(mmu_update, batch, NULL, domid) < 0)
+ goto out;
+
+ nr -= batch;
+ addr += range;
+ }
+
+ err = 0;
+out:
+
+ flush_tlb_all();
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_range);