Messages in this thread | | | Date | Thu, 1 Sep 2022 18:15:01 +0530 | Subject | Re: [PATCHv4 1/8] x86/cpu: Add CPUID feature bit for VNMI | From | "Shukla, Santosh" <> |
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Hi Jim,
On 9/1/2022 5:12 AM, Jim Mattson wrote: > On Mon, Aug 29, 2022 at 3:09 AM Santosh Shukla <santosh.shukla@amd.com> wrote: >> >> VNMI feature allows the hypervisor to inject NMI into the guest w/o >> using Event injection mechanism, The benefit of using VNMI over the >> event Injection that does not require tracking the Guest's NMI state and >> intercepting the IRET for the NMI completion. VNMI achieves that by >> exposing 3 capability bits in VMCB intr_cntrl which helps with >> virtualizing NMI injection and NMI_Masking. >> >> The presence of this feature is indicated via the CPUID function >> 0x8000000A_EDX[25]. >> >> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> >> Signed-off-by: Santosh Shukla <santosh.shukla@amd.com> >> --- >> arch/x86/include/asm/cpufeatures.h | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h >> index ef4775c6db01..33e3603be09e 100644 >> --- a/arch/x86/include/asm/cpufeatures.h >> +++ b/arch/x86/include/asm/cpufeatures.h >> @@ -356,6 +356,7 @@ >> #define X86_FEATURE_VGIF (15*32+16) /* Virtual GIF */ >> #define X86_FEATURE_X2AVIC (15*32+18) /* Virtual x2apic */ >> #define X86_FEATURE_V_SPEC_CTRL (15*32+20) /* Virtual SPEC_CTRL */ >> +#define X86_FEATURE_V_NMI (15*32+25) /* Virtual NMI */ >> #define X86_FEATURE_SVME_ADDR_CHK (15*32+28) /* "" SVME addr check */ > > Why is it "V_NMI," but "VGIF"? > I guess you are asking why I chose V_NMI and not VNMI, right? if so then there are two reasons for going with V_NMI - IP bits are named in order V_NMI, V_NMI_MASK, and V_NMI_ENABLE style and also Intel already using VNMI (X86_FEATURE_VNMI)
Thanks, Santosh
> Reviewed-by: Jim Mattson <jmattson@google.com>
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