The patch titled
KVM: MMU: add audit code to check mappings, etc are correct
has been added to the -mm tree. Its filename is
kvm-mmu-add-audit-code-to-check-mappings-etc-are-correct.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: KVM: MMU: add audit code to check mappings, etc are correct
From: Avi Kivity <avi@xxxxxxxxxxxx>
Signed-off-by: Avi Kivity <avi@xxxxxxxxxxxx>
Acked-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
drivers/kvm/mmu.c | 187 +++++++++++++++++++++++++++++++++++-
drivers/kvm/paging_tmpl.h | 4
2 files changed, 189 insertions(+), 2 deletions(-)
diff -puN drivers/kvm/mmu.c~kvm-mmu-add-audit-code-to-check-mappings-etc-are-correct drivers/kvm/mmu.c
--- a/drivers/kvm/mmu.c~kvm-mmu-add-audit-code-to-check-mappings-etc-are-correct
+++ a/drivers/kvm/mmu.c
@@ -26,8 +26,31 @@
#include "vmx.h"
#include "kvm.h"
-#define pgprintk(x...) do { printk(x); } while (0)
-#define rmap_printk(x...) do { printk(x); } while (0)
+#undef MMU_DEBUG
+
+#undef AUDIT
+
+#ifdef AUDIT
+static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg);
+#else
+static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg) {}
+#endif
+
+#ifdef MMU_DEBUG
+
+#define pgprintk(x...) do { if (dbg) printk(x); } while (0)
+#define rmap_printk(x...) do { if (dbg) printk(x); } while (0)
+
+#else
+
+#define pgprintk(x...) do { } while (0)
+#define rmap_printk(x...) do { } while (0)
+
+#endif
+
+#if defined(MMU_DEBUG) || defined(AUDIT)
+static int dbg = 1;
+#endif
#define ASSERT(x) \
if (!(x)) { \
@@ -1271,3 +1294,163 @@ void kvm_mmu_slot_remove_write_access(st
}
}
}
+
+#ifdef AUDIT
+
+static const char *audit_msg;
+
+static gva_t canonicalize(gva_t gva)
+{
+#ifdef CONFIG_X86_64
+ gva = (long long)(gva << 16) >> 16;
+#endif
+ return gva;
+}
+
+static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte,
+ gva_t va, int level)
+{
+ u64 *pt = __va(page_pte & PT64_BASE_ADDR_MASK);
+ int i;
+ gva_t va_delta = 1ul << (PAGE_SHIFT + 9 * (level - 1));
+
+ for (i = 0; i < PT64_ENT_PER_PAGE; ++i, va += va_delta) {
+ u64 ent = pt[i];
+
+ if (!ent & PT_PRESENT_MASK)
+ continue;
+
+ va = canonicalize(va);
+ if (level > 1)
+ audit_mappings_page(vcpu, ent, va, level - 1);
+ else {
+ gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, va);
+ hpa_t hpa = gpa_to_hpa(vcpu, gpa);
+
+ if ((ent & PT_PRESENT_MASK)
+ && (ent & PT64_BASE_ADDR_MASK) != hpa)
+ printk(KERN_ERR "audit error: (%s) levels %d"
+ " gva %lx gpa %llx hpa %llx ent %llx\n",
+ audit_msg, vcpu->mmu.root_level,
+ va, gpa, hpa, ent);
+ }
+ }
+}
+
+static void audit_mappings(struct kvm_vcpu *vcpu)
+{
+ int i;
+
+ if (vcpu->mmu.root_level == 4)
+ audit_mappings_page(vcpu, vcpu->mmu.root_hpa, 0, 4);
+ else
+ for (i = 0; i < 4; ++i)
+ if (vcpu->mmu.pae_root[i] & PT_PRESENT_MASK)
+ audit_mappings_page(vcpu,
+ vcpu->mmu.pae_root[i],
+ i << 30,
+ 2);
+}
+
+static int count_rmaps(struct kvm_vcpu *vcpu)
+{
+ int nmaps = 0;
+ int i, j, k;
+
+ for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
+ struct kvm_memory_slot *m = &vcpu->kvm->memslots[i];
+ struct kvm_rmap_desc *d;
+
+ for (j = 0; j < m->npages; ++j) {
+ struct page *page = m->phys_mem[j];
+
+ if (!page->private)
+ continue;
+ if (!(page->private & 1)) {
+ ++nmaps;
+ continue;
+ }
+ d = (struct kvm_rmap_desc *)(page->private & ~1ul);
+ while (d) {
+ for (k = 0; k < RMAP_EXT; ++k)
+ if (d->shadow_ptes[k])
+ ++nmaps;
+ else
+ break;
+ d = d->more;
+ }
+ }
+ }
+ return nmaps;
+}
+
+static int count_writable_mappings(struct kvm_vcpu *vcpu)
+{
+ int nmaps = 0;
+ struct kvm_mmu_page *page;
+ int i;
+
+ list_for_each_entry(page, &vcpu->kvm->active_mmu_pages, link) {
+ u64 *pt = __va(page->page_hpa);
+
+ if (page->role.level != PT_PAGE_TABLE_LEVEL)
+ continue;
+
+ for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
+ u64 ent = pt[i];
+
+ if (!(ent & PT_PRESENT_MASK))
+ continue;
+ if (!(ent & PT_WRITABLE_MASK))
+ continue;
+ ++nmaps;
+ }
+ }
+ return nmaps;
+}
+
+static void audit_rmap(struct kvm_vcpu *vcpu)
+{
+ int n_rmap = count_rmaps(vcpu);
+ int n_actual = count_writable_mappings(vcpu);
+
+ if (n_rmap != n_actual)
+ printk(KERN_ERR "%s: (%s) rmap %d actual %d\n",
+ __FUNCTION__, audit_msg, n_rmap, n_actual);
+}
+
+static void audit_write_protection(struct kvm_vcpu *vcpu)
+{
+ struct kvm_mmu_page *page;
+
+ list_for_each_entry(page, &vcpu->kvm->active_mmu_pages, link) {
+ hfn_t hfn;
+ struct page *pg;
+
+ if (page->role.metaphysical)
+ continue;
+
+ hfn = gpa_to_hpa(vcpu, (gpa_t)page->gfn << PAGE_SHIFT)
+ >> PAGE_SHIFT;
+ pg = pfn_to_page(hfn);
+ if (pg->private)
+ printk(KERN_ERR "%s: (%s) shadow page has writable"
+ " mappings: gfn %lx role %x\n",
+ __FUNCTION__, audit_msg, page->gfn,
+ page->role.word);
+ }
+}
+
+static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg)
+{
+ int olddbg = dbg;
+
+ dbg = 0;
+ audit_msg = msg;
+ audit_rmap(vcpu);
+ audit_write_protection(vcpu);
+ audit_mappings(vcpu);
+ dbg = olddbg;
+}
+
+#endif
diff -puN drivers/kvm/paging_tmpl.h~kvm-mmu-add-audit-code-to-check-mappings-etc-are-correct drivers/kvm/paging_tmpl.h
--- a/drivers/kvm/paging_tmpl.h~kvm-mmu-add-audit-code-to-check-mappings-etc-are-correct
+++ a/drivers/kvm/paging_tmpl.h
@@ -355,6 +355,7 @@ static int FNAME(page_fault)(struct kvm_
int r;
pgprintk("%s: addr %lx err %x\n", __FUNCTION__, addr, error_code);
+ kvm_mmu_audit(vcpu, "pre page fault");
r = mmu_topup_memory_caches(vcpu);
if (r)
@@ -402,6 +403,7 @@ static int FNAME(page_fault)(struct kvm_
pgprintk("%s: io work, no access\n", __FUNCTION__);
inject_page_fault(vcpu, addr,
error_code | PFERR_PRESENT_MASK);
+ kvm_mmu_audit(vcpu, "post page fault (io)");
return 0;
}
@@ -410,10 +412,12 @@ static int FNAME(page_fault)(struct kvm_
*/
if (pte_present && !fixed && !write_pt) {
inject_page_fault(vcpu, addr, error_code);
+ kvm_mmu_audit(vcpu, "post page fault (guest)");
return 0;
}
++kvm_stat.pf_fixed;
+ kvm_mmu_audit(vcpu, "post page fault (fixed)");
return write_pt;
}
_
Patches currently in -mm which might be from avi@xxxxxxxxxxxx are
kvm-fix-gfp_kernel-alloc-in-atomic-section-bug.patch
kvm-use-raw_smp_processor_id-instead-of-smp_processor_id-where-applicable.patch
kvm-recover-after-an-arch-module-load-failure.patch
kvm-improve-interrupt-response.patch
kvm-prevent-stale-bits-in-cr0-and-cr4.patch
kvm-mmu-implement-simple-reverse-mapping.patch
kvm-mmu-teach-the-page-table-walker-to-track-guest-page-table-gfns.patch
kvm-mmu-load-the-pae-pdptrs-on-cr3-change-like-the-processor-does.patch
kvm-mmu-fold-fetch_guest-into-init_walker.patch
kvm-mu-special-treatment-for-shadow-pae-root-pages.patch
kvm-mmu-use-the-guest-pdptrs-instead-of-mapping-cr3-in-pae-mode.patch
kvm-mmu-make-the-shadow-page-tables-also-special-case-pae.patch
kvm-mmu-make-kvm_mmu_alloc_page-return-a-kvm_mmu_page-pointer.patch
kvm-mmu-shadow-page-table-caching.patch
kvm-mmu-write-protect-guest-pages-when-a-shadow-is-created-for-them.patch
kvm-mmu-let-the-walker-extract-the-target-page-gfn-from-the-pte.patch
kvm-mmu-support-emulated-writes-into-ram.patch
kvm-mmu-zap-shadow-page-table-entries-on-writes-to-guest-page-tables.patch
kvm-mmu-if-emulating-an-instruction-fails-try-unprotecting-the-page.patch
kvm-mmu-implement-child-shadow-unlinking.patch
kvm-mmu-kvm_mmu_put_page-only-removes-one-link-to-the-page.patch
kvm-mmu-oom-handling.patch
kvm-mmu-remove-invlpg-interception.patch
kvm-mmu-remove-release_pt_page_64.patch
kvm-mmu-handle-misaligned-accesses-to-write-protected-guest-page-tables.patch
kvm-mmu-ove-is_empty_shadow_page-above-kvm_mmu_free_page.patch
kvm-mmu-ensure-freed-shadow-pages-are-clean.patch
kvm-mmu-if-an-empty-shadow-page-is-not-empty-report-more-info.patch
kvm-mmu-page-table-write-flood-protection.patch
kvm-mmu-never-free-a-shadow-page-actively-serving-as-a-root.patch
kvm-mmu-fix-cmpxchg8b-emulation.patch
kvm-mmu-treat-user-mode-faults-as-a-hint-that-a-page-is-no-longer-a-page-table.patch
kvm-mmu-free-pages-on-kvm-destruction.patch
kvm-mmu-replace-atomic-allocations-by-preallocated-objects.patch
kvm-mmu-detect-oom-conditions-and-propagate-error-to-userspace.patch
kvm-mmu-flush-guest-tlb-when-reducing-permissions-on-a-pte.patch
kvm-mmu-destroy-mmu-while-we-still-have-a-vcpu-left.patch
kvm-mmu-add-audit-code-to-check-mappings-etc-are-correct.patch
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