On Thu, Mar 30, 2017 at 2:55 AM, Paolo Bonzini <pbonzini@xxxxxxxxxx> 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@xxxxxxxxxx>
The check can never be true because the SDM says so explicitly: Bit 8
is "Reserved if bit 7 is 0 (cleared to 0)."
Reviewed-by: Jim Mattson <jmattson@xxxxxxxxxx>
> ---
> 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.
> --
> 1.8.3.1
>
>
