2017-07-24 21:36 GMT+08:00 Paolo Bonzini <pbonzini@xxxxxxxxxx>:
> On 23/07/2017 03:05, Wanpeng Li wrote:
>> From: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
>>
>> 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.
>>
>> Reported-by: Jim Mattson <jmattson@xxxxxxxxxx>
>> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
>> Cc: Radim Krčmář <rkrcmar@xxxxxxxxxx>
>> Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
>> ---
>> arch/x86/kvm/vmx.c | 6 ++++++
>> 1 file changed, 6 insertions(+)
>>
>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
>> index 29fd8af..8a213f2 100644
>> --- a/arch/x86/kvm/vmx.c
>> +++ b/arch/x86/kvm/vmx.c
>> @@ -2429,6 +2429,8 @@ static void skip_emulated_instruction(struct kvm_vcpu *vcpu)
>> vmx_set_interrupt_shadow(vcpu, 0);
>> }
>>
>> +static bool nested_vmx_is_page_fault_vmexit(struct vmcs12 *vmcs12, u16 error_code);
>> +
>> /*
>> * KVM wants to inject page-faults which it got to the guest. This function
>> * checks whether in a nested guest, we need to inject them to L1 or L2.
>> @@ -2442,6 +2444,10 @@ static int nested_vmx_check_exception(struct kvm_vcpu *vcpu)
>> (nr == PF_VECTOR && vcpu->arch.exception.nested_apf)))
>> return 0;
>>
>> + if (nr == PF_VECTOR && !vcpu->arch.exception.nested_apf &&
>> + !nested_vmx_is_page_fault_vmexit(vmcs12, vcpu->arch.exception.error_code))
>> + return 0;
>
> This is wrong, the check must replace "(vmcs12->exception_bitmap & (1u
> << nr)" if nr == PF_VECTOR.
How about something like this:
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 29fd8af..52afd23 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2439,7 +2439,8 @@ static int nested_vmx_check_exception(struct
kvm_vcpu *vcpu)
unsigned int nr = vcpu->arch.exception.nr;
if (!((vmcs12->exception_bitmap & (1u << nr)) ||
- (nr == PF_VECTOR && vcpu->arch.exception.nested_apf)))
+ (nr == PF_VECTOR && (vcpu->arch.exception.nested_apf ||
+ nested_vmx_is_page_fault_vmexit(vmcs12,
vcpu->arch.exception.error_code)))))
return 0;
if (vcpu->arch.exception.nested_apf) {
Regards,
Wanpeng Li
