2021-02-12 00:44:36

by Sean Christopherson

Subject: [PATCH 1/3] KVM: SVM: Intercept INVPCID when it's disabled to inject #UD

Intercept INVPCID if it's disabled in the guest, even when using NPT,
as KVM needs to inject #UD in this case.

Fixes: 4407a797e941 ("KVM: SVM: Enable INVPCID feature on AMD")
Cc: Babu Moger <[email protected]>
Signed-off-by: Sean Christopherson <[email protected]>
---
arch/x86/kvm/svm/svm.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 42d4710074a6..ca9706c2f99b 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1103,12 +1103,12 @@ static u64 svm_write_l1_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
static void svm_check_invpcid(struct vcpu_svm *svm)
{
/*
- * Intercept INVPCID instruction only if shadow page table is
- * enabled. Interception is not required with nested page table
- * enabled.
+ * Intercept INVPCID if shadow paging is enabled to sync/free shadow
+ * roots, or if INVPCID is disabled in the guest to inject #UD.
*/
if (kvm_cpu_cap_has(X86_FEATURE_INVPCID)) {
- if (!npt_enabled)
+ if (!npt_enabled ||
+ !guest_cpuid_has(&svm->vcpu, X86_FEATURE_INVPCID))
svm_set_intercept(svm, INTERCEPT_INVPCID);
else
svm_clr_intercept(svm, INTERCEPT_INVPCID);
--
2.30.0.478.g8a0d178c01-goog

2021-02-12 01:08:20

by Jim Mattson

Subject: Re: [PATCH 1/3] KVM: SVM: Intercept INVPCID when it's disabled to inject #UD

On Thu, Feb 11, 2021 at 4:34 PM Sean Christopherson <[email protected]> wrote:
>
> Intercept INVPCID if it's disabled in the guest, even when using NPT,
> as KVM needs to inject #UD in this case.
>
> Fixes: 4407a797e941 ("KVM: SVM: Enable INVPCID feature on AMD")
> Cc: Babu Moger <[email protected]>
> Signed-off-by: Sean Christopherson <[email protected]>
Reviewed-by: Jim Mattson <[email protected]>