Inject a #GP if the memory operand received by INVCPID is non-canonical.
The APM clearly states that the intercept takes priority over all #GP
checks except the CPL0 restriction.
Of course, that begs the question of how the CPU generates a linear
address in the first place. Tracing confirms that EXITINFO1 does hold a
linear address, at least for 64-bit mode guests (hooray GS prefix).
Unfortunately, the APM says absolutely nothing about the EXITINFO fields
for INVPCID intercepts, so it's not at all clear what's supposed to
happen.
Add a FIXME to call out that KVM still does the wrong thing for 32-bit
guests, and if the stack segment is used for the memory operand.
Cc: Babu Moger <babu.moger@xxxxxxx>
Cc: Jim Mattson <jmattson@xxxxxxxxxx>
Fixes: 4407a797e941 ("KVM: SVM: Enable INVPCID feature on AMD")
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/svm/svm.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index b8aa0f36850f..63268d940ce1 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3272,6 +3272,17 @@ static int invpcid_interception(struct kvm_vcpu *vcpu)
type = svm->vmcb->control.exit_info_2;
gva = svm->vmcb->control.exit_info_1;
+ /*
+ * FIXME: Perform segment checks for 32-bit mode, and inject #SS if the
+ * stack segment is used. The intercept takes priority over all
+ * #GP checks except CPL>0, but somehow still generates a linear
+ * address? The APM is sorely lacking.
+ */
+ if (is_noncanonical_address(gva, vcpu, 0)) {
+ kvm_queue_exception_e(vcpu, GP_VECTOR, 0);
+ return 1;
+ }
+
return kvm_handle_invpcid(vcpu, type, gva);
}
base-commit: fed48e2967f402f561d80075a20c5c9e16866e53
--
2.48.1.658.g4767266eb4-goog
