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authorIngo Molnar <mingo@elte.hu>2008-10-15 13:46:29 +0200
committerIngo Molnar <mingo@elte.hu>2008-10-15 13:46:29 +0200
commitb2aaf8f74cdc84a9182f6cabf198b7763bcb9d40 (patch)
tree53ccb1c2c14751fe69cf93102e76e97021f6df07 /arch/x86/xen/mmu.c
parent4f962d4d65923d7b722192e729840cfb79af0a5a (diff)
parent278429cff8809958d25415ba0ed32b59866ab1a8 (diff)
Merge branch 'linus' into stackprotector
Conflicts: arch/x86/kernel/Makefile include/asm-x86/pda.h
Diffstat (limited to 'arch/x86/xen/mmu.c')
-rw-r--r--arch/x86/xen/mmu.c840
1 files changed, 714 insertions, 126 deletions
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index df40bf74ea7..ae173f6edd8 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -40,12 +40,15 @@
*/
#include <linux/sched.h>
#include <linux/highmem.h>
+#include <linux/debugfs.h>
#include <linux/bug.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
+#include <asm/fixmap.h>
#include <asm/mmu_context.h>
#include <asm/paravirt.h>
+#include <asm/linkage.h>
#include <asm/xen/hypercall.h>
#include <asm/xen/hypervisor.h>
@@ -55,16 +58,200 @@
#include "multicalls.h"
#include "mmu.h"
+#include "debugfs.h"
-xmaddr_t arbitrary_virt_to_machine(unsigned long address)
+#define MMU_UPDATE_HISTO 30
+
+#ifdef CONFIG_XEN_DEBUG_FS
+
+static struct {
+ u32 pgd_update;
+ u32 pgd_update_pinned;
+ u32 pgd_update_batched;
+
+ u32 pud_update;
+ u32 pud_update_pinned;
+ u32 pud_update_batched;
+
+ u32 pmd_update;
+ u32 pmd_update_pinned;
+ u32 pmd_update_batched;
+
+ u32 pte_update;
+ u32 pte_update_pinned;
+ u32 pte_update_batched;
+
+ u32 mmu_update;
+ u32 mmu_update_extended;
+ u32 mmu_update_histo[MMU_UPDATE_HISTO];
+
+ u32 prot_commit;
+ u32 prot_commit_batched;
+
+ u32 set_pte_at;
+ u32 set_pte_at_batched;
+ u32 set_pte_at_pinned;
+ u32 set_pte_at_current;
+ u32 set_pte_at_kernel;
+} mmu_stats;
+
+static u8 zero_stats;
+
+static inline void check_zero(void)
+{
+ if (unlikely(zero_stats)) {
+ memset(&mmu_stats, 0, sizeof(mmu_stats));
+ zero_stats = 0;
+ }
+}
+
+#define ADD_STATS(elem, val) \
+ do { check_zero(); mmu_stats.elem += (val); } while(0)
+
+#else /* !CONFIG_XEN_DEBUG_FS */
+
+#define ADD_STATS(elem, val) do { (void)(val); } while(0)
+
+#endif /* CONFIG_XEN_DEBUG_FS */
+
+/*
+ * 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)
+
+
+#define P2M_ENTRIES_PER_PAGE (PAGE_SIZE / sizeof(unsigned long))
+#define TOP_ENTRIES (MAX_DOMAIN_PAGES / P2M_ENTRIES_PER_PAGE)
+
+/* Placeholder for holes in the address space */
+static unsigned long p2m_missing[P2M_ENTRIES_PER_PAGE] __page_aligned_data =
+ { [ 0 ... P2M_ENTRIES_PER_PAGE-1 ] = ~0UL };
+
+ /* Array of pointers to pages containing p2m entries */
+static unsigned long *p2m_top[TOP_ENTRIES] __page_aligned_data =
+ { [ 0 ... TOP_ENTRIES - 1] = &p2m_missing[0] };
+
+/* Arrays of p2m arrays expressed in mfns used for save/restore */
+static unsigned long p2m_top_mfn[TOP_ENTRIES] __page_aligned_bss;
+
+static unsigned long p2m_top_mfn_list[TOP_ENTRIES / P2M_ENTRIES_PER_PAGE]
+ __page_aligned_bss;
+
+static inline unsigned p2m_top_index(unsigned long pfn)
+{
+ BUG_ON(pfn >= MAX_DOMAIN_PAGES);
+ return pfn / P2M_ENTRIES_PER_PAGE;
+}
+
+static inline unsigned p2m_index(unsigned long pfn)
+{
+ return pfn % P2M_ENTRIES_PER_PAGE;
+}
+
+/* Build the parallel p2m_top_mfn structures */
+void xen_setup_mfn_list_list(void)
{
+ unsigned pfn, idx;
+
+ for(pfn = 0; pfn < MAX_DOMAIN_PAGES; pfn += P2M_ENTRIES_PER_PAGE) {
+ unsigned topidx = p2m_top_index(pfn);
+
+ p2m_top_mfn[topidx] = virt_to_mfn(p2m_top[topidx]);
+ }
+
+ for(idx = 0; idx < ARRAY_SIZE(p2m_top_mfn_list); idx++) {
+ unsigned topidx = idx * P2M_ENTRIES_PER_PAGE;
+ p2m_top_mfn_list[idx] = virt_to_mfn(&p2m_top_mfn[topidx]);
+ }
+
+ BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
+
+ HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list =
+ virt_to_mfn(p2m_top_mfn_list);
+ HYPERVISOR_shared_info->arch.max_pfn = xen_start_info->nr_pages;
+}
+
+/* Set up p2m_top to point to the domain-builder provided p2m pages */
+void __init xen_build_dynamic_phys_to_machine(void)
+{
+ unsigned long *mfn_list = (unsigned long *)xen_start_info->mfn_list;
+ unsigned long max_pfn = min(MAX_DOMAIN_PAGES, xen_start_info->nr_pages);
+ unsigned pfn;
+
+ for(pfn = 0; pfn < max_pfn; pfn += P2M_ENTRIES_PER_PAGE) {
+ unsigned topidx = p2m_top_index(pfn);
+
+ p2m_top[topidx] = &mfn_list[pfn];
+ }
+}
+
+unsigned long get_phys_to_machine(unsigned long pfn)
+{
+ unsigned topidx, idx;
+
+ if (unlikely(pfn >= MAX_DOMAIN_PAGES))
+ return INVALID_P2M_ENTRY;
+
+ topidx = p2m_top_index(pfn);
+ idx = p2m_index(pfn);
+ return p2m_top[topidx][idx];
+}
+EXPORT_SYMBOL_GPL(get_phys_to_machine);
+
+static void alloc_p2m(unsigned long **pp, unsigned long *mfnp)
+{
+ unsigned long *p;
+ unsigned i;
+
+ p = (void *)__get_free_page(GFP_KERNEL | __GFP_NOFAIL);
+ BUG_ON(p == NULL);
+
+ for(i = 0; i < P2M_ENTRIES_PER_PAGE; i++)
+ p[i] = INVALID_P2M_ENTRY;
+
+ if (cmpxchg(pp, p2m_missing, p) != p2m_missing)
+ free_page((unsigned long)p);
+ else
+ *mfnp = virt_to_mfn(p);
+}
+
+void set_phys_to_machine(unsigned long pfn, unsigned long mfn)
+{
+ unsigned topidx, idx;
+
+ if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) {
+ BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);
+ return;
+ }
+
+ if (unlikely(pfn >= MAX_DOMAIN_PAGES)) {
+ BUG_ON(mfn != INVALID_P2M_ENTRY);
+ return;
+ }
+
+ topidx = p2m_top_index(pfn);
+ if (p2m_top[topidx] == p2m_missing) {
+ /* no need to allocate a page to store an invalid entry */
+ if (mfn == INVALID_P2M_ENTRY)
+ return;
+ alloc_p2m(&p2m_top[topidx], &p2m_top_mfn[topidx]);
+ }
+
+ idx = p2m_index(pfn);
+ p2m_top[topidx][idx] = mfn;
+}
+
+xmaddr_t arbitrary_virt_to_machine(void *vaddr)
+{
+ unsigned long address = (unsigned long)vaddr;
unsigned int level;
pte_t *pte = lookup_address(address, &level);
unsigned offset = address & ~PAGE_MASK;
BUG_ON(pte == NULL);
- return XMADDR((pte_mfn(*pte) << PAGE_SHIFT) + offset);
+ return XMADDR(((phys_addr_t)pte_mfn(*pte) << PAGE_SHIFT) + offset);
}
void make_lowmem_page_readonly(void *vaddr)
@@ -98,59 +285,84 @@ void make_lowmem_page_readwrite(void *vaddr)
}
-void xen_set_pmd(pmd_t *ptr, pmd_t val)
+static bool xen_page_pinned(void *ptr)
+{
+ struct page *page = virt_to_page(ptr);
+
+ return PagePinned(page);
+}
+
+static void xen_extend_mmu_update(const struct mmu_update *update)
{
struct multicall_space mcs;
struct mmu_update *u;
- preempt_disable();
+ mcs = xen_mc_extend_args(__HYPERVISOR_mmu_update, sizeof(*u));
+
+ if (mcs.mc != NULL) {
+ ADD_STATS(mmu_update_extended, 1);
+ ADD_STATS(mmu_update_histo[mcs.mc->args[1]], -1);
+
+ mcs.mc->args[1]++;
+
+ if (mcs.mc->args[1] < MMU_UPDATE_HISTO)
+ ADD_STATS(mmu_update_histo[mcs.mc->args[1]], 1);
+ else
+ ADD_STATS(mmu_update_histo[0], 1);
+ } else {
+ ADD_STATS(mmu_update, 1);
+ mcs = __xen_mc_entry(sizeof(*u));
+ MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
+ ADD_STATS(mmu_update_histo[1], 1);
+ }
- mcs = xen_mc_entry(sizeof(*u));
u = mcs.args;
- u->ptr = virt_to_machine(ptr).maddr;
- u->val = pmd_val_ma(val);
- MULTI_mmu_update(mcs.mc, u, 1, NULL, DOMID_SELF);
+ *u = *update;
+}
+
+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);
+
+ ADD_STATS(pmd_update_batched, paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU);
xen_mc_issue(PARAVIRT_LAZY_MMU);
preempt_enable();
}
+void xen_set_pmd(pmd_t *ptr, pmd_t val)
+{
+ ADD_STATS(pmd_update, 1);
+
+ /* If page is not pinned, we can just update the entry
+ directly */
+ if (!xen_page_pinned(ptr)) {
+ *ptr = val;
+ return;
+ }
+
+ ADD_STATS(pmd_update_pinned, 1);
+
+ 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)
{
- pgd_t *pgd;
- pud_t *pud;
- pmd_t *pmd;
- pte_t *pte;
-
- pgd = swapper_pg_dir + pgd_index(vaddr);
- if (pgd_none(*pgd)) {
- BUG();
- return;
- }
- pud = pud_offset(pgd, vaddr);
- if (pud_none(*pud)) {
- BUG();
- return;
- }
- pmd = pmd_offset(pud, vaddr);
- if (pmd_none(*pmd)) {
- BUG();
- return;
- }
- pte = pte_offset_kernel(pmd, vaddr);
- /* <mfn,flags> stored as-is, to permit clearing entries */
- xen_set_pte(pte, mfn_pte(mfn, flags));
-
- /*
- * It's enough to flush this one mapping.
- * (PGE mappings get flushed as well)
- */
- __flush_tlb_one(vaddr);
+ set_pte_vaddr(vaddr, mfn_pte(mfn, flags));
}
void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
@@ -160,12 +372,18 @@ void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
if (mm == &init_mm)
preempt_disable();
+ ADD_STATS(set_pte_at, 1);
+// ADD_STATS(set_pte_at_pinned, xen_page_pinned(ptep));
+ ADD_STATS(set_pte_at_current, mm == current->mm);
+ ADD_STATS(set_pte_at_kernel, mm == &init_mm);
+
if (mm == current->mm || mm == &init_mm) {
if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
struct multicall_space mcs;
mcs = xen_mc_entry(0);
MULTI_update_va_mapping(mcs.mc, addr, pteval, 0);
+ ADD_STATS(set_pte_at_batched, 1);
xen_mc_issue(PARAVIRT_LAZY_MMU);
goto out;
} else
@@ -179,13 +397,36 @@ out:
preempt_enable();
}
+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 */
+ 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;
+
+ 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);
+
+ ADD_STATS(prot_commit, 1);
+ ADD_STATS(prot_commit_batched, paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU);
+
+ 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_MASK) >> PAGE_SHIFT;
- pteval_t flags = val & ~PTE_MASK;
- val = (mfn_to_pfn(mfn) << PAGE_SHIFT) | flags;
+ 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;
@@ -194,9 +435,9 @@ static pteval_t pte_mfn_to_pfn(pteval_t val)
static pteval_t pte_pfn_to_mfn(pteval_t val)
{
if (val & _PAGE_PRESENT) {
- unsigned long pfn = (val & PTE_MASK) >> PAGE_SHIFT;
- pteval_t flags = val & ~PTE_MASK;
- val = (pfn_to_mfn(pfn) << PAGE_SHIFT) | flags;
+ unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
+ pteval_t flags = val & PTE_FLAGS_MASK;
+ val = ((pteval_t)pfn_to_mfn(pfn) << PAGE_SHIFT) | flags;
}
return val;
@@ -229,34 +470,61 @@ pmdval_t xen_pmd_val(pmd_t pmd)
return pte_mfn_to_pfn(pmd.pmd);
}
-void xen_set_pud(pud_t *ptr, pud_t val)
+void xen_set_pud_hyper(pud_t *ptr, pud_t val)
{
- struct multicall_space mcs;
- struct mmu_update *u;
+ struct mmu_update u;
preempt_disable();
- mcs = xen_mc_entry(sizeof(*u));
- u = mcs.args;
- u->ptr = virt_to_machine(ptr).maddr;
- u->val = pud_val_ma(val);
- MULTI_mmu_update(mcs.mc, u, 1, NULL, DOMID_SELF);
+ 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);
+
+ ADD_STATS(pud_update_batched, paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU);
xen_mc_issue(PARAVIRT_LAZY_MMU);
preempt_enable();
}
+void xen_set_pud(pud_t *ptr, pud_t val)
+{
+ ADD_STATS(pud_update, 1);
+
+ /* If page is not pinned, we can just update the entry
+ directly */
+ if (!xen_page_pinned(ptr)) {
+ *ptr = val;
+ return;
+ }
+
+ ADD_STATS(pud_update_pinned, 1);
+
+ xen_set_pud_hyper(ptr, val);
+}
+
void xen_set_pte(pte_t *ptep, pte_t pte)
{
+ ADD_STATS(pte_update, 1);
+// ADD_STATS(pte_update_pinned, xen_page_pinned(ptep));
+ ADD_STATS(pte_update_batched, paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU);
+
+#ifdef CONFIG_X86_PAE
ptep->pte_high = pte.pte_high;
smp_wmb();
ptep->pte_low = pte.pte_low;
+#else
+ *ptep = pte;
+#endif
}
+#ifdef CONFIG_X86_PAE
void xen_set_pte_atomic(pte_t *ptep, pte_t pte)
{
- set_64bit((u64 *)ptep, pte_val_ma(pte));
+ set_64bit((u64 *)ptep, native_pte_val(pte));
}
void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
@@ -268,8 +536,9 @@ void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
void xen_pmd_clear(pmd_t *pmdp)
{
- xen_set_pmd(pmdp, __pmd(0));
+ set_pmd(pmdp, __pmd(0));
}
+#endif /* CONFIG_X86_PAE */
pmd_t xen_make_pmd(pmdval_t pmd)
{
@@ -277,95 +546,218 @@ pmd_t xen_make_pmd(pmdval_t pmd)
return native_make_pmd(pmd);
}
+#if PAGETABLE_LEVELS == 4
+pudval_t xen_pud_val(pud_t pud)
+{
+ return pte_mfn_to_pfn(pud.pud);
+}
+
+pud_t xen_make_pud(pudval_t pud)
+{
+ pud = pte_pfn_to_mfn(pud);
+
+ return native_make_pud(pud);
+}
+
+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
+ */
+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();
+}
+
+void xen_set_pgd(pgd_t *ptr, pgd_t val)
+{
+ pgd_t *user_ptr = xen_get_user_pgd(ptr);
+
+ ADD_STATS(pgd_update, 1);
+
+ /* 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;
+ }
+
+ ADD_STATS(pgd_update_pinned, 1);
+ ADD_STATS(pgd_update_batched, paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU);
+
+ /* 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 pte_limit. In the normal case
- this will be TASK_SIZE, but at boot we need to pin up to
- FIXADDR_TOP. But the important bit is that we don't pin beyond
- there, because then we start getting into Xen's ptes.
-*/
-static int pgd_walk(pgd_t *pgd_base, int (*func)(struct page *, enum pt_level),
- unsigned long limit)
-{
- pgd_t *pgd = pgd_base;
+ * (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,
+ int (*func)(struct mm_struct *mm, struct page *,
+ enum pt_level),
+ unsigned long limit)
+{
+ pgd_t *pgd = mm->pgd;
int flush = 0;
- unsigned long addr = 0;
- unsigned long pgd_next;
+ unsigned hole_low, hole_high;
+ unsigned pgdidx_limit, pudidx_limit, pmdidx_limit;
+ unsigned pgdidx, pudidx, pmdidx;
- BUG_ON(limit > FIXADDR_TOP);
+ /* The limit is the last byte to be touched */
+ limit--;
+ BUG_ON(limit >= FIXADDR_TOP);
if (xen_feature(XENFEAT_auto_translated_physmap))
return 0;
- for (; addr != FIXADDR_TOP; pgd++, addr = pgd_next) {
+ /*
+ * 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;
- unsigned long pud_limit, pud_next;
- pgd_next = pud_limit = pgd_addr_end(addr, FIXADDR_TOP);
+ if (pgdidx >= hole_low && pgdidx < hole_high)
+ continue;
- if (!pgd_val(*pgd))
+ if (!pgd_val(pgd[pgdidx]))
continue;
- pud = pud_offset(pgd, 0);
+ pud = pud_offset(&pgd[pgdidx], 0);
if (PTRS_PER_PUD > 1) /* not folded */
- flush |= (*func)(virt_to_page(pud), PT_PUD);
+ flush |= (*func)(mm, virt_to_page(pud), PT_PUD);
- for (; addr != pud_limit; pud++, addr = pud_next) {
+ for (pudidx = 0; pudidx < PTRS_PER_PUD; pudidx++) {
pmd_t *pmd;
- unsigned long pmd_limit;
-
- pud_next = pud_addr_end(addr, pud_limit);
- if (pud_next < limit)
- pmd_limit = pud_next;
- else
- pmd_limit = limit;
+ if (pgdidx == pgdidx_limit &&
+ pudidx > pudidx_limit)
+ goto out;
- if (pud_none(*pud))
+ if (pud_none(pud[pudidx]))
continue;
- pmd = pmd_offset(pud, 0);
+ pmd = pmd_offset(&pud[pudidx], 0);
if (PTRS_PER_PMD > 1) /* not folded */
- flush |= (*func)(virt_to_page(pmd), PT_PMD);
+ flush |= (*func)(mm, virt_to_page(pmd), PT_PMD);
+
+ for (pmdidx = 0; pmdidx < PTRS_PER_PMD; pmdidx++) {
+ struct page *pte;
- for (; addr != pmd_limit; pmd++) {
- addr += (PAGE_SIZE * PTRS_PER_PTE);
- if ((pmd_limit-1) < (addr-1)) {
- addr = pmd_limit;
- break;
- }
+ if (pgdidx == pgdidx_limit &&
+ pudidx == pudidx_limit &&
+ pmdidx > pmdidx_limit)
+ goto out;
- if (pmd_none(*pmd))
+ if (pmd_none(pmd[pmdidx]))
continue;
- flush |= (*func)(pmd_page(*pmd), PT_PTE);
+ pte = pmd_page(pmd[pmdidx]);
+ flush |= (*func)(mm, pte, PT_PTE);
}
}
}
- flush |= (*func)(virt_to_page(pgd_base), PT_PGD);
+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 spinlock_t *lock_pte(struct page *page)
+/* 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 NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS
+#if USE_SPLIT_PTLOCKS
ptl = __pte_lockptr(page);
- spin_lock(ptl);
+ spin_lock_nest_lock(ptl, &mm->page_table_lock);
#endif
return ptl;
}
-static void do_unlock(void *v)
+static void xen_pte_unlock(void *v)
{
spinlock_t *ptl = v;
spin_unlock(ptl);
@@ -383,7 +775,8 @@ static void xen_do_pin(unsigned level, unsigned long pfn)
MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
}
-static int pin_page(struct page *page, enum pt_level level)
+static int xen_pin_page(struct mm_struct *mm, struct page *page,
+ enum pt_level level)
{
unsigned pgfl = TestSetPagePinned(page);
int flush;
@@ -402,21 +795,40 @@ static int pin_page(struct page *page, enum pt_level level)
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 = lock_pte(page);
+ 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 (level == PT_PTE)
+ if (ptl) {
xen_do_pin(MMUEXT_PIN_L1_TABLE, pfn);
- if (ptl) {
/* Queue a deferred unlock for when this batch
is completed. */
- xen_mc_callback(do_unlock, ptl);
+ xen_mc_callback(xen_pte_unlock, ptl);
}
}
@@ -426,25 +838,78 @@ static int pin_page(struct page *page, enum pt_level level)
/* 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. */
-void xen_pgd_pin(pgd_t *pgd)
+static void __xen_pgd_pin(struct mm_struct *mm, pgd_t *pgd)
{
xen_mc_batch();
- if (pgd_walk(pgd, pin_page, TASK_SIZE)) {
+ if (xen_pgd_walk(mm, xen_pin_page, USER_LIMIT)) {
/* re-enable interrupts for kmap_flush_unused */
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, virt_to_page(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);
}
-/* 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 __init int mark_pinned(struct page *page, enum pt_level level)
+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)
+{
+ unsigned long flags;
+ struct page *page;
+
+ spin_lock_irqsave(&pgd_lock, flags);
+
+ 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_irqrestore(&pgd_lock, flags);
+}
+
+/*
+ * 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 __init int xen_mark_pinned(struct mm_struct *mm, struct page *page,
+ enum pt_level level)
{
SetPagePinned(page);
return 0;
@@ -452,10 +917,11 @@ static __init int mark_pinned(struct page *page, enum pt_level level)
void __init xen_mark_init_mm_pinned(void)
{
- pgd_walk(init_mm.pgd, mark_pinned, FIXADDR_TOP);
+ xen_pgd_walk(&init_mm, xen_mark_pinned, FIXADDR_TOP);
}
-static int unpin_page(struct page *page, enum pt_level level)
+static int xen_unpin_page(struct mm_struct *mm, struct page *page,
+ enum pt_level level)
{
unsigned pgfl = TestClearPagePinned(page);
@@ -465,10 +931,18 @@ static int unpin_page(struct page *page, enum pt_level level)
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 = lock_pte(page);
+ ptl = xen_pte_lock(page, mm);
- xen_do_pin(MMUEXT_UNPIN_TABLE, pfn);
+ if (ptl)
+ xen_do_pin(MMUEXT_UNPIN_TABLE, pfn);
}
mcs = __xen_mc_entry(0);
@@ -479,7 +953,7 @@ static int unpin_page(struct page *page, enum pt_level level)
if (ptl) {
/* unlock when batch completed */
- xen_mc_callback(do_unlock, ptl);
+ xen_mc_callback(xen_pte_unlock, ptl);
}
}
@@ -487,28 +961,72 @@ static int unpin_page(struct page *page, enum pt_level level)
}
/* Release a pagetables pages back as normal RW */
-static void xen_pgd_unpin(pgd_t *pgd)
+static void __xen_pgd_unpin(struct mm_struct *mm, pgd_t *pgd)
{
xen_mc_batch();
xen_do_pin(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
- pgd_walk(pgd, unpin_page, TASK_SIZE);
+#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, virt_to_page(pgd_page(pgd[pgd_index(TASK_SIZE)])),
+ PT_PMD);
+#endif
+
+ xen_pgd_walk(mm, 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)
+{
+ unsigned long flags;
+ struct page *page;
+
+ spin_lock_irqsave(&pgd_lock, flags);
+
+ 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_irqrestore(&pgd_lock, flags);
+}
+
void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
{
spin_lock(&next->page_table_lock);
- xen_pgd_pin(next->pgd);
+ xen_pgd_pin(next);
spin_unlock(&next->page_table_lock);
}
void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
{
spin_lock(&mm->page_table_lock);
- xen_pgd_pin(mm->pgd);
+ xen_pgd_pin(mm);
spin_unlock(&mm->page_table_lock);
}
@@ -519,8 +1037,15 @@ void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
static void drop_other_mm_ref(void *info)
{
struct mm_struct *mm = info;
+ struct mm_struct *active_mm;
+
+#ifdef CONFIG_X86_64
+ active_mm = read_pda(active_mm);
+#else
+ active_mm = __get_cpu_var(cpu_tlbstate).active_mm;
+#endif
- if (__get_cpu_var(cpu_tlbstate).active_mm == mm)
+ if (active_mm == mm)
leave_mm(smp_processor_id());
/* If this cpu still has a stale cr3 reference, then make sure
@@ -531,7 +1056,7 @@ static void drop_other_mm_ref(void *info)
}
}
-static void drop_mm_ref(struct mm_struct *mm)
+static void xen_drop_mm_ref(struct mm_struct *mm)
{
cpumask_t mask;
unsigned cpu;
@@ -558,10 +1083,10 @@ static void drop_mm_ref(struct mm_struct *mm)
}
if (!cpus_empty(mask))
- xen_smp_call_function_mask(mask, drop_other_mm_ref, mm, 1);
+ smp_call_function_mask(mask, drop_other_mm_ref, mm, 1);
}
#else
-static void drop_mm_ref(struct mm_struct *mm)
+static void xen_drop_mm_ref(struct mm_struct *mm)
{
if (current->active_mm == mm)
load_cr3(swapper_pg_dir);
@@ -585,14 +1110,77 @@ static void drop_mm_ref(struct mm_struct *mm)
void xen_exit_mmap(struct mm_struct *mm)
{
get_cpu(); /* make sure we don't move around */
- drop_mm_ref(mm);
+ 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 (PagePinned(virt_to_page(mm->pgd)))
- xen_pgd_unpin(mm->pgd);
+ if (xen_page_pinned(mm->pgd))
+ xen_pgd_unpin(mm);
spin_unlock(&mm->page_table_lock);
}
+
+#ifdef CONFIG_XEN_DEBUG_FS
+
+static struct dentry *d_mmu_debug;
+
+static int __init xen_mmu_debugfs(void)
+{
+ struct dentry *d_xen = xen_init_debugfs();
+
+ if (d_xen == NULL)
+ return -ENOMEM;
+
+ d_mmu_debug = debugfs_create_dir("mmu", d_xen);
+
+ debugfs_create_u8("zero_stats", 0644, d_mmu_debug, &zero_stats);
+
+ debugfs_create_u32("pgd_update", 0444, d_mmu_debug, &mmu_stats.pgd_update);
+ debugfs_create_u32("pgd_update_pinned", 0444, d_mmu_debug,
+ &mmu_stats.pgd_update_pinned);
+ debugfs_create_u32("pgd_update_batched", 0444, d_mmu_debug,
+ &mmu_stats.pgd_update_pinned);
+
+ debugfs_create_u32("pud_update", 0444, d_mmu_debug, &mmu_stats.pud_update);
+ debugfs_create_u32("pud_update_pinned", 0444, d_mmu_debug,
+ &mmu_stats.pud_update_pinned);
+ debugfs_create_u32("pud_update_batched", 0444, d_mmu_debug,
+ &mmu_stats.pud_update_pinned);
+
+ debugfs_create_u32("pmd_update", 0444, d_mmu_debug, &mmu_stats.pmd_update);
+ debugfs_create_u32("pmd_update_pinned", 0444, d_mmu_debug,
+ &mmu_stats.pmd_update_pinned);
+ debugfs_create_u32("pmd_update_batched", 0444, d_mmu_debug,
+ &mmu_stats.pmd_update_pinned);
+
+ debugfs_create_u32("pte_update", 0444, d_mmu_debug, &mmu_stats.pte_update);
+// debugfs_create_u32("pte_update_pinned", 0444, d_mmu_debug,
+// &mmu_stats.pte_update_pinned);
+ debugfs_create_u32("pte_update_batched", 0444, d_mmu_debug,
+ &mmu_stats.pte_update_pinned);
+
+ debugfs_create_u32("mmu_update", 0444, d_mmu_debug, &mmu_stats.mmu_update);
+ debugfs_create_u32("mmu_update_extended", 0444, d_mmu_debug,
+ &mmu_stats.mmu_update_extended);
+ xen_debugfs_create_u32_array("mmu_update_histo", 0444, d_mmu_debug,
+ mmu_stats.mmu_update_histo, 20);
+
+ debugfs_create_u32("set_pte_at", 0444, d_mmu_debug, &mmu_stats.set_pte_at);
+ debugfs_create_u32("set_pte_at_batched", 0444, d_mmu_debug,
+ &mmu_stats.set_pte_at_batched);
+ debugfs_create_u32("set_pte_at_current", 0444, d_mmu_debug,
+ &mmu_stats.set_pte_at_current);
+ debugfs_create_u32("set_pte_at_kernel", 0444, d_mmu_debug,
+ &mmu_stats.set_pte_at_kernel);
+
+ debugfs_create_u32("prot_commit", 0444, d_mmu_debug, &mmu_stats.prot_commit);
+ debugfs_create_u32("prot_commit_batched", 0444, d_mmu_debug,
+ &mmu_stats.prot_commit_batched);
+
+ return 0;
+}
+fs_initcall(xen_mmu_debugfs);
+
+#endif /* CONFIG_XEN_DEBUG_FS */