| Message ID | 1473013367-12173-1-git-send-email-jan.dakinevich@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
2016-09-05 2:22 GMT+08:00 Jan Dakinevich <jan.dakinevich@gmail.com>: > If EPT support is exposed to L1 hypervisor, guest linear-address field > of VMCS should contain GVA of L2, the access to which caused EPT violation. > > Signed-off-by: Jan Dakinevich <jan.dakinevich@gmail.com> > --- > arch/x86/kvm/vmx.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 5cede40..a4bb2bd 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -10500,6 +10500,9 @@ static void prepare_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12, > vmcs12->guest_pdptr3 = vmcs_read64(GUEST_PDPTR3); > } > > + if (nested_cpu_has_ept(vmcs12)) > + vmcs12->guest_linear_address = vmcs_readl(GUEST_LINEAR_ADDRESS); > + No, nested_ept_inject_page_fault() will set vmcs12->guest_linear_address after L0 walks L1's EPT page table and finds that the mapping is invalid if nested EPT is enabled. prepare_vmcs12() just copies the vmcs field that could have changed by the L2 guest or the exit-information etc instead of all fields since other fields are modified by L1 with VMWRITE, which already writes to vmcs12 directly. Regards, Wanpeng Li -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 09/05/2016 03:49 AM, Wanpeng Li wrote: > 2016-09-05 2:22 GMT+08:00 Jan Dakinevich <jan.dakinevich@gmail.com>: >> If EPT support is exposed to L1 hypervisor, guest linear-address field >> of VMCS should contain GVA of L2, the access to which caused EPT violation. >> >> Signed-off-by: Jan Dakinevich <jan.dakinevich@gmail.com> >> --- >> arch/x86/kvm/vmx.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c >> index 5cede40..a4bb2bd 100644 >> --- a/arch/x86/kvm/vmx.c >> +++ b/arch/x86/kvm/vmx.c >> @@ -10500,6 +10500,9 @@ static void prepare_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12, >> vmcs12->guest_pdptr3 = vmcs_read64(GUEST_PDPTR3); >> } >> >> + if (nested_cpu_has_ept(vmcs12)) >> + vmcs12->guest_linear_address = vmcs_readl(GUEST_LINEAR_ADDRESS); >> + > > No, nested_ept_inject_page_fault() will set > vmcs12->guest_linear_address after L0 walks L1's EPT page table and > finds that the mapping is invalid if nested EPT is enabled. Acctually, nested_ept_inject_page_fault() doesn't do that, the routine sets only vmcs12->guest_physical_address, but vmcs12->guest_linear_address remains untouched. As result, after EPT fault from L2, vmcs_readl(GUEST_LINEAR_ADDRESS) in L1 always returns 0. > prepare_vmcs12() just copies the vmcs field that could have changed by > the L2 guest or the exit-information etc instead of all fields since > other fields are modified by L1 with VMWRITE, which already writes to > vmcs12 directly. Yes, and guest linear-address considered as a part of exit information, provided by hardware. > > Regards, > Wanpeng Li >
On 05/09/2016 15:02, Jan Dakinevich wrote: > > No, nested_ept_inject_page_fault() will set > > vmcs12->guest_linear_address after L0 walks L1's EPT page table and > > finds that the mapping is invalid if nested EPT is enabled. > > Acctually, nested_ept_inject_page_fault() doesn't do that, the routine > sets only vmcs12->guest_physical_address, but > vmcs12->guest_linear_address remains untouched. As result, after EPT > fault from L2, vmcs_readl(GUEST_LINEAR_ADDRESS) in L1 always returns 0. > > > prepare_vmcs12() just copies the vmcs field that could have changed by > > the L2 guest or the exit-information etc instead of all fields since > > other fields are modified by L1 with VMWRITE, which already writes to > > vmcs12 directly. > > Yes, and guest linear-address considered as a part of exit information, > provided by hardware. I agree. The patch seems okay to me, but I'll leave a couple days more to Wanpeng. Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
2016-09-05 21:02 GMT+08:00 Jan Dakinevich <jan.dakinevich@gmail.com>: > > > On 09/05/2016 03:49 AM, Wanpeng Li wrote: >> 2016-09-05 2:22 GMT+08:00 Jan Dakinevich <jan.dakinevich@gmail.com>: >>> If EPT support is exposed to L1 hypervisor, guest linear-address field >>> of VMCS should contain GVA of L2, the access to which caused EPT violation. >>> >>> Signed-off-by: Jan Dakinevich <jan.dakinevich@gmail.com> >>> --- >>> arch/x86/kvm/vmx.c | 3 +++ >>> 1 file changed, 3 insertions(+) >>> >>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c >>> index 5cede40..a4bb2bd 100644 >>> --- a/arch/x86/kvm/vmx.c >>> +++ b/arch/x86/kvm/vmx.c >>> @@ -10500,6 +10500,9 @@ static void prepare_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12, >>> vmcs12->guest_pdptr3 = vmcs_read64(GUEST_PDPTR3); >>> } >>> >>> + if (nested_cpu_has_ept(vmcs12)) >>> + vmcs12->guest_linear_address = vmcs_readl(GUEST_LINEAR_ADDRESS); >>> + >> >> No, nested_ept_inject_page_fault() will set >> vmcs12->guest_linear_address after L0 walks L1's EPT page table and >> finds that the mapping is invalid if nested EPT is enabled. > > Acctually, nested_ept_inject_page_fault() doesn't do that, the routine > sets only vmcs12->guest_physical_address, but > vmcs12->guest_linear_address remains untouched. As result, after EPT > fault from L2, vmcs_readl(GUEST_LINEAR_ADDRESS) in L1 always returns 0. Agreed, I misread guest_linear_address as guest_physical_address. > >> prepare_vmcs12() just copies the vmcs field that could have changed by >> the L2 guest or the exit-information etc instead of all fields since >> other fields are modified by L1 with VMWRITE, which already writes to >> vmcs12 directly. > > Yes, and guest linear-address considered as a part of exit information, > provided by hardware. Thanks for the patch. Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com> -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 5cede40..a4bb2bd 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -10500,6 +10500,9 @@ static void prepare_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12, vmcs12->guest_pdptr3 = vmcs_read64(GUEST_PDPTR3); } + if (nested_cpu_has_ept(vmcs12)) + vmcs12->guest_linear_address = vmcs_readl(GUEST_LINEAR_ADDRESS); + if (nested_cpu_has_vid(vmcs12)) vmcs12->guest_intr_status = vmcs_read16(GUEST_INTR_STATUS);
If EPT support is exposed to L1 hypervisor, guest linear-address field of VMCS should contain GVA of L2, the access to which caused EPT violation. Signed-off-by: Jan Dakinevich <jan.dakinevich@gmail.com> --- arch/x86/kvm/vmx.c | 3 +++ 1 file changed, 3 insertions(+)