When KVM intercepts #GP on an SVM instruction, it re-injects the #GP if the instruction was executed with a mis-algined RAX. However, a #GP should also be reinjected if RAX contains an illegal GPA, according to the APM, one of #GP conditions is: rAX referenced a physical address above the maximum supported physical address. Replace the PAGE_MASK check with page_address_valid(), which checks both page-alignment as well as the legality of the GPA based on the vCPU's MAXPHYADDR. Use kvm_register_read() to read RAX to avoid page_address_valid() failing on 32-bit due to garbage in the higher bits. Note that this is currently only a problem if KVM is running an L2 guest and ends up synthesizing a #VMEXIT to L1, as the RAX check takes precedence over the intercept. Otherwise, if KVM emulates the instruction, kvm_vcpu_map() should fail on illegal GPAs and inject a #GP anyway. However, following patches will change the failure behavior of kvm_vcpu_map(), so make sure the #GP interception handler does this appropriately. Opportunistically drop a teaser FIXME about the SVM instructions handling on #GP belonging in the emulator. Fixes: 82a11e9c6fa2 ("KVM: SVM: Add emulation support for #GP triggered by SVM instructions") Fixes: d1cba6c92237 ("KVM: x86: nSVM: test eax for 4K alignment for GP errata workaround") Suggested-by: Sean Christopherson Signed-off-by: Yosry Ahmed --- arch/x86/kvm/svm/svm.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 392a5088f20bf..3122a98745ab7 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -2277,10 +2277,12 @@ static int gp_interception(struct kvm_vcpu *vcpu) if (x86_decode_emulated_instruction(vcpu, 0, NULL, 0) != EMULATION_OK) goto reinject; + /* FIXME: Handle SVM instructions through the emulator */ svm_exit_code = svm_instr_exit_code(vcpu); if (svm_exit_code) { - /* All SVM instructions expect page aligned RAX */ - if (svm->vmcb->save.rax & ~PAGE_MASK) + unsigned long rax = kvm_register_read(vcpu, VCPU_REGS_RAX); + + if (!page_address_valid(vcpu, rax)) goto reinject; if (is_guest_mode(vcpu)) { -- 2.53.0.851.ga537e3e6e9-goog