From d4b69c3d1471a7fa48111b3bb6489e7c5a5bcb2a Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Mon, 24 Feb 2025 09:45:22 -0800 Subject: [PATCH] KVM: SVM: Inject #GP if memory operand for INVPCID is non-canonical 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 Cc: Jim Mattson Fixes: 4407a797e941 ("KVM: SVM: Enable INVPCID feature on AMD") Link: https://lore.kernel.org/r/20250224174522.2363400-1-seanjc@google.com Signed-off-by: Sean Christopherson --- 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 0603d047a1f04..2b4d93f25c7dc 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); } -- 2.39.5