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Date: Mon, 3 Apr 2017 13:17:02 +0200 From: David Hildenbrand <david@...hat.com> To: Paolo Bonzini <pbonzini@...hat.com>, linux-kernel@...r.kernel.org, kvm@...r.kernel.org Subject: Re: [PATCH 2/6] KVM: VMX: remove bogus check for invalid EPT violation On 30.03.2017 11:55, Paolo Bonzini wrote: > handle_ept_violation is checking for "guest-linear-address invalid" + > "not a paging-structure walk". However, _all_ EPT violations without > a valid guest linear address are paging structure walks, because those > EPT violations happen when loading the guest PDPTEs. > > Therefore, the check can never be true, and even if it were, KVM doesn't > care about the guest linear address; it only uses the guest *physical* > address VMCS field. So, remove the check altogether. > > Signed-off-by: Paolo Bonzini <pbonzini@...hat.com> > --- > arch/x86/kvm/vmx.c | 14 -------------- > 1 file changed, 14 deletions(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 0e61b9226bf2..1c372600a962 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -6208,23 +6208,9 @@ static int handle_ept_violation(struct kvm_vcpu *vcpu) > unsigned long exit_qualification; > gpa_t gpa; > u32 error_code; > - int gla_validity; > > exit_qualification = vmcs_readl(EXIT_QUALIFICATION); > > - gla_validity = (exit_qualification >> 7) & 0x3; > - if (gla_validity == 0x2) { > - printk(KERN_ERR "EPT: Handling EPT violation failed!\n"); > - printk(KERN_ERR "EPT: GPA: 0x%lx, GVA: 0x%lx\n", > - (long unsigned int)vmcs_read64(GUEST_PHYSICAL_ADDRESS), > - vmcs_readl(GUEST_LINEAR_ADDRESS)); > - printk(KERN_ERR "EPT: Exit qualification is 0x%lx\n", > - (long unsigned int)exit_qualification); > - vcpu->run->exit_reason = KVM_EXIT_UNKNOWN; > - vcpu->run->hw.hardware_exit_reason = EXIT_REASON_EPT_VIOLATION; > - return 0; > - } > - > /* > * EPT violation happened while executing iret from NMI, > * "blocked by NMI" bit has to be set before next VM entry. > Reviewed-by: David Hildenbrand <david@...hat.com> -- Thanks, David
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