RE: [PATCH v5 2/5] x86/cpufeatures: Add X86_FEATURE_SGX_EUPDATESVN feature flag

[Reshetova, Elena]

> On Mon, 2025-05-19 at 10:24 +0300, Elena Reshetova wrote:
> > Add a flag indicating whenever ENCLS[EUPDATESVN] SGX instruction
> > is supported. This will be used by SGX driver to perform CPU
> > SVN updates.
> >
> > Signed-off-by: Elena Reshetova <elena.reshetova@xxxxxxxxx>
> > ---
> >  arch/x86/include/asm/cpufeatures.h       | 1 +
> >  arch/x86/kernel/cpu/scattered.c          | 1 +
> >  tools/arch/x86/include/asm/cpufeatures.h | 1 +
> >  3 files changed, 3 insertions(+)
> >
> > diff --git a/arch/x86/include/asm/cpufeatures.h
> b/arch/x86/include/asm/cpufeatures.h
> > index 6c2c152d8a67..ed0c0fa5822a 100644
> > --- a/arch/x86/include/asm/cpufeatures.h
> > +++ b/arch/x86/include/asm/cpufeatures.h
> > @@ -481,6 +481,7 @@
> >  #define X86_FEATURE_AMD_HETEROGENEOUS_CORES (21*32 + 6) /*
> Heterogeneous Core Topology */
> >  #define X86_FEATURE_AMD_WORKLOAD_CLASS	(21*32 + 7) /*
> Workload Classification */
> >  #define X86_FEATURE_PREFER_YMM		(21*32 + 8) /* Avoid ZMM
> registers due to downclocking */
> > +#define X86_FEATURE_SGX_EUPDATESVN	(21*32 + 9) /* Support for
> ENCLS[EUPDATESVN] instruction */
> >
> >  /*
> >   * BUG word(s)
> > diff --git a/arch/x86/kernel/cpu/scattered.c
> b/arch/x86/kernel/cpu/scattered.c
> > index 16f3ca30626a..a7e1fcedca3c 100644
> > --- a/arch/x86/kernel/cpu/scattered.c
> > +++ b/arch/x86/kernel/cpu/scattered.c
> > @@ -41,6 +41,7 @@ static const struct cpuid_bit cpuid_bits[] = {
> >  	{ X86_FEATURE_PER_THREAD_MBA,		CPUID_ECX,  0,
> 0x00000010, 3 },
> >  	{ X86_FEATURE_SGX1,			CPUID_EAX,  0, 0x00000012, 0
> },
> >  	{ X86_FEATURE_SGX2,			CPUID_EAX,  1, 0x00000012, 0
> },
> > +	{ X86_FEATURE_SGX_EUPDATESVN,	CPUID_EAX, 10, 0x00000012,
> 0 },
> >  	{ X86_FEATURE_SGX_EDECCSSA,		CPUID_EAX, 11,
> 0x00000012, 0 },
> >  	{ X86_FEATURE_HW_PSTATE,		CPUID_EDX,  7, 0x80000007, 0
> },
> >  	{ X86_FEATURE_CPB,			CPUID_EDX,  9, 0x80000007, 0
> },
> > diff --git a/tools/arch/x86/include/asm/cpufeatures.h
> b/tools/arch/x86/include/asm/cpufeatures.h
> > index 6c2c152d8a67..ed0c0fa5822a 100644
> > --- a/tools/arch/x86/include/asm/cpufeatures.h
> > +++ b/tools/arch/x86/include/asm/cpufeatures.h
> > @@ -481,6 +481,7 @@
> >  #define X86_FEATURE_AMD_HETEROGENEOUS_CORES (21*32 + 6) /*
> Heterogeneous Core Topology */
> >  #define X86_FEATURE_AMD_WORKLOAD_CLASS	(21*32 + 7) /*
> Workload Classification */
> >  #define X86_FEATURE_PREFER_YMM		(21*32 + 8) /* Avoid ZMM
> registers due to downclocking */
> > +#define X86_FEATURE_SGX_EUPDATESVN	(21*32 + 9) /* Support for
> ENCLS[EUPDATESVN] instruction */
> >
> >
> 
> 
> Additionally, the new feature bit should be added to the CPUID dependency
> table:
> 
> --- a/arch/x86/kernel/cpu/cpuid-deps.c
> +++ b/arch/x86/kernel/cpu/cpuid-deps.c
> @@ -78,6 +78,7 @@ static const struct cpuid_dep cpuid_deps[] = {
>         { X86_FEATURE_SGX_LC,                   X86_FEATURE_SGX       },
>         { X86_FEATURE_SGX1,                     X86_FEATURE_SGX       },
>         { X86_FEATURE_SGX2,                     X86_FEATURE_SGX1      },
> +       { X86_FEATURE_SGX_EUPDATESVN,           X86_FEATURE_SGX1      },
>         { X86_FEATURE_SGX_EDECCSSA,             X86_FEATURE_SGX1      },
>         { X86_FEATURE_XFD,                      X86_FEATURE_XSAVES    },
>         { X86_FEATURE_XFD,                      X86_FEATURE_XGETBV1   },

This one I missed, will add.