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authorMaxim Levitsky <mlevitsk@redhat.com>2021-05-03 14:54:43 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2021-05-03 17:25:37 +0200
commitc74ad08f3333db2e44d3346b863f6d10d35e37dd (patch)
tree3344853b461f63f5ed583b7218742c3466248007 /arch
parentKVM: nSVM: fix a typo in svm_leave_nested (diff)
downloadlinux-c74ad08f3333db2e44d3346b863f6d10d35e37dd.tar.xz
linux-c74ad08f3333db2e44d3346b863f6d10d35e37dd.zip
KVM: nSVM: fix few bugs in the vmcb02 caching logic
* Define and use an invalid GPA (all ones) for init value of last and current nested vmcb physical addresses. * Reset the current vmcb12 gpa to the invalid value when leaving the nested mode, similar to what is done on nested vmexit. * Reset the last seen vmcb12 address when disabling the nested SVM, as it relies on vmcb02 fields which are freed at that point. Fixes: 4995a3685f1b ("KVM: SVM: Use a separate vmcb for the nested L2 guest") Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20210503125446.1353307-3-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/include/asm/kvm_host.h1
-rw-r--r--arch/x86/kvm/svm/nested.c11
-rw-r--r--arch/x86/kvm/svm/svm.c4
3 files changed, 14 insertions, 2 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index cbbcee0a84f9..848956bb3cf1 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -113,6 +113,7 @@
#define VALID_PAGE(x) ((x) != INVALID_PAGE)
#define UNMAPPED_GVA (~(gpa_t)0)
+#define INVALID_GPA (~(gpa_t)0)
/* KVM Hugepage definitions for x86 */
#define KVM_MAX_HUGEPAGE_LEVEL PG_LEVEL_1G
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 3321220f3deb..a88c64e004c3 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -872,6 +872,15 @@ void svm_free_nested(struct vcpu_svm *svm)
__free_page(virt_to_page(svm->nested.vmcb02.ptr));
svm->nested.vmcb02.ptr = NULL;
+ /*
+ * When last_vmcb12_gpa matches the current vmcb12 gpa,
+ * some vmcb12 fields are not loaded if they are marked clean
+ * in the vmcb12, since in this case they are up to date already.
+ *
+ * When the vmcb02 is freed, this optimization becomes invalid.
+ */
+ svm->nested.last_vmcb12_gpa = INVALID_GPA;
+
svm->nested.initialized = false;
}
@@ -884,6 +893,8 @@ void svm_leave_nested(struct vcpu_svm *svm)
if (is_guest_mode(vcpu)) {
svm->nested.nested_run_pending = 0;
+ svm->nested.vmcb12_gpa = INVALID_GPA;
+
leave_guest_mode(vcpu);
svm_switch_vmcb(svm, &svm->vmcb01);
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 9790c73f2a32..be5cf612ab1f 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1235,8 +1235,8 @@ static void init_vmcb(struct kvm_vcpu *vcpu)
svm->current_vmcb->asid_generation = 0;
svm->asid = 0;
- svm->nested.vmcb12_gpa = 0;
- svm->nested.last_vmcb12_gpa = 0;
+ svm->nested.vmcb12_gpa = INVALID_GPA;
+ svm->nested.last_vmcb12_gpa = INVALID_GPA;
vcpu->arch.hflags = 0;
if (!kvm_pause_in_guest(vcpu->kvm)) {