diff mbox series

[RFC,v6,28/92] kvm: x86: consult the page tracking from kvm_mmu_get_page() and __direct_map()

Message ID 20190809160047.8319-29-alazar@bitdefender.com (mailing list archive)
State New, archived
Headers show
Series VM introspection | expand

Commit Message

Adalbert Lazăr Aug. 9, 2019, 3:59 p.m. UTC 
From: Mihai Donțu <mdontu@bitdefender.com>

KVM doesn't normally need to keep track that closely to page access bits,
however for the introspection subsystem this is essential.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Link: https://marc.info/?l=kvm&m=149804987417131&w=2
CC: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Mihai Donțu <mdontu@bitdefender.com>
Signed-off-by: Adalbert Lazăr <alazar@bitdefender.com>
---
 arch/x86/kvm/mmu.c | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 9eaf6cc776a9..810e3e5bd575 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2491,6 +2491,20 @@  static void clear_sp_write_flooding_count(u64 *spte)
 	__clear_sp_write_flooding_count(sp);
 }
 
+static unsigned int kvm_mmu_page_track_acc(struct kvm_vcpu *vcpu, gfn_t gfn,
+					   unsigned int acc)
+{
+	if (kvm_page_track_is_active(vcpu, gfn, KVM_PAGE_TRACK_PREREAD))
+		acc &= ~ACC_USER_MASK;
+	if (kvm_page_track_is_active(vcpu, gfn, KVM_PAGE_TRACK_PREWRITE) ||
+	    kvm_page_track_is_active(vcpu, gfn, KVM_PAGE_TRACK_WRITE))
+		acc &= ~ACC_WRITE_MASK;
+	if (kvm_page_track_is_active(vcpu, gfn, KVM_PAGE_TRACK_PREEXEC))
+		acc &= ~ACC_EXEC_MASK;
+
+	return acc;
+}
+
 static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
 					     gfn_t gfn,
 					     gva_t gaddr,
@@ -2511,7 +2525,7 @@  static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
 	role.direct = direct;
 	if (role.direct)
 		role.cr4_pae = 0;
-	role.access = access;
+	role.access = kvm_mmu_page_track_acc(vcpu, gfn, access);
 	if (!vcpu->arch.mmu->direct_map
 	    && vcpu->arch.mmu->root_level <= PT32_ROOT_LEVEL) {
 		quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level));
@@ -3234,7 +3248,10 @@  static int __direct_map(struct kvm_vcpu *vcpu, int write, int map_writable,
 
 	for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) {
 		if (iterator.level == level) {
-			emulate = mmu_set_spte(vcpu, iterator.sptep, ACC_ALL,
+			unsigned int acc = kvm_mmu_page_track_acc(vcpu, gfn,
+								  ACC_ALL);
+
+			emulate = mmu_set_spte(vcpu, iterator.sptep, acc,
 					       write, level, gfn, pfn, prefault,
 					       map_writable);
 			direct_pte_prefetch(vcpu, iterator.sptep);