Re: [v2 PATCH] KVM: nVMX: consult PFEC_MASK and PFEC_MATCH when generating #PF VM-exit

Paolo Bonzini
2014-12-18T08:46:10Z

On 16/12/2014 20:35, Eugene Korenevsky wrote:
> When generating #PF VM-exit, check equality:
> (PFEC & PFEC_MASK) == PFEC_MATCH
> If there is equality, the 14 bit of exception bitmap is used to take decision
> about generating #PF VM-exit. If there is inequality, inverted 14 bit is used.
>
> Signed-off-by: Eugene Korenevsky <ekorenevsky@gmail.com>
> ---
> arch/x86/kvm/vmx.c | 15 +++++++++++++--
> 1 file changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 09ccf6c..a8ef8265 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -8206,6 +8206,18 @@ static void nested_ept_uninit_mmu_context(struct kvm_vcpu *vcpu)
> vcpu->arch.walk_mmu = &vcpu->arch.mmu;
> }
>
> +static bool nested_vmx_is_page_fault_vmexit(struct vmcs12 *vmcs12,
> + u16 error_code)
> +{
> + bool inequality, bit;
> +
> + bit = (vmcs12->exception_bitmap & (1u << PF_VECTOR)) != 0;
> + inequality =
> + (error_code & vmcs12->page_fault_error_code_mask) !=
> + vmcs12->page_fault_error_code_match;
> + return inequality ^ bit;
> +}
> +
> static void vmx_inject_page_fault_nested(struct kvm_vcpu *vcpu,
> struct x86_exception *fault)
> {
> @@ -8213,8 +8225,7 @@ static void vmx_inject_page_fault_nested(struct kvm_vcpu *vcpu,
>
> WARN_ON(!is_guest_mode(vcpu));
>
> - /* TODO: also check PFEC_MATCH/MASK, not just EB.PF. */
> - if (vmcs12->exception_bitmap & (1u << PF_VECTOR))
> + if (nested_vmx_is_page_fault_vmexit(vmcs12, fault->error_code))
> nested_vmx_vmexit(vcpu, to_vmx(vcpu)->exit_reason,
> vmcs_read32(VM_EXIT_INTR_INFO),
> vmcs_readl(EXIT_QUALIFICATION));
>

Applied to kvm/queue, thanks.

Paolo