Re: [PATCH v5 6/8] i386: Add RDT feature flags.

[Hendrik Wüthrich]

On Wed, Jan 8, 2025 at 7:39 PM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Fri, Dec 13, 2024 at 05:26:43PM +0000, Hendrik Wuethrich wrote:
> > From: ‪Hendrik Wüthrich <whendrik@google.com>
> >
> > Add RDT features to feature word / TCG.
> >
> > Signed-off-by: Hendrik Wüthrich <whendrik@google.com>
> > ---
> >  target/i386/cpu.c | 30 ++++++++++++++++++++++++++++--
> >  target/i386/cpu.h |  2 ++
> >  2 files changed, 30 insertions(+), 2 deletions(-)
> >
> > diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> > index c6e6cff19d..6f14d6fc62 100644
> > --- a/target/i386/cpu.c
> > +++ b/target/i386/cpu.c
> > @@ -869,7 +869,8 @@ void x86_cpu_vendor_words2str(char *dst, uint32_t 
> > vendor1,
> >            CPUID_7_0_EBX_CLFLUSHOPT |            \
> >            CPUID_7_0_EBX_CLWB | CPUID_7_0_EBX_MPX | CPUID_7_0_EBX_FSGSBASE 
> > | \
> >            CPUID_7_0_EBX_ERMS | CPUID_7_0_EBX_AVX2 | CPUID_7_0_EBX_RDSEED | 
> > \
> > -          CPUID_7_0_EBX_SHA_NI | CPUID_7_0_EBX_KERNEL_FEATURES)
> > +          CPUID_7_0_EBX_SHA_NI | CPUID_7_0_EBX_KERNEL_FEATURES | \
> > +          CPUID_7_0_EBX_PQM | CPUID_7_0_EBX_PQE)
> >            /* missing:
> >            CPUID_7_0_EBX_HLE
> >            CPUID_7_0_EBX_INVPCID, CPUID_7_0_EBX_RTM */
> > @@ -906,6 +907,7 @@ void x86_cpu_vendor_words2str(char *dst, uint32_t 
> > vendor1,
> >  #define TCG_SGX_12_0_EBX_FEATURES 0
> >  #define TCG_SGX_12_1_EAX_FEATURES 0
> >  #define TCG_24_0_EBX_FEATURES 0
> > +#define TCG_RDT_F_0_EDX_FEATURES CPUID_F_0_EDX_L3
> >
> >  #if defined CONFIG_USER_ONLY
> >  #define CPUID_8000_0008_EBX_KERNEL_FEATURES (CPUID_8000_0008_EBX_IBPB | \
> > @@ -1063,7 +1065,7 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
> >              "fsgsbase", "tsc-adjust", "sgx", "bmi1",
> >              "hle", "avx2", "fdp-excptn-only", "smep",
> >              "bmi2", "erms", "invpcid", "rtm",
> > -            NULL, "zero-fcs-fds", "mpx", NULL,
> > +            "rdt-m", "zero-fcs-fds", "mpx", "rdt-a",
> >              "avx512f", "avx512dq", "rdseed", "adx",
> >              "smap", "avx512ifma", "pcommit", "clflushopt",
> >              "clwb", "intel-pt", "avx512pf", "avx512er",
> > @@ -1651,6 +1653,30 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
> >          },
> >          .tcg_features = TCG_SGX_12_1_EAX_FEATURES,
> >      },
> > +
> > +    [FEAT_RDT_10_0_EBX] = {
> > +        .type = CPUID_FEATURE_WORD,
> > +        .feat_names = {
> > +            NULL, "l3-cat", "l2-cat", "mba"
> > +        },
> > +        .cpuid = {
> > +            .eax = 0x10,
> > +            .needs_ecx = true, .ecx = 0,
> > +            .reg = R_EBX,
> > +        }
> > +    },
> > +    [FEAT_RDT_F_0_EDX] = {
> > +        .type = CPUID_FEATURE_WORD,
> > +        .feat_names = {
> > +            [1] = "l3-cmt"
> > +        },
> > +        .cpuid = {
> > +            .eax = 0xf,
> > +            .needs_ecx = true, .ecx = 0,
> > +            .reg = R_EDX,
> > +        },
> > +        .tcg_features = TCG_RDT_F_0_EDX_FEATURES,
> > +    },
> >  };
> >
>
> Should these be made unavailable if rdt device is compiled out?

This doesn't seem to be happening in similar situations in the
surrounding code, so I don't think so.

>
> >  typedef struct FeatureMask {
> > diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> > index a1ec2d5dde..2b5a5986de 100644
> > --- a/target/i386/cpu.h
> > +++ b/target/i386/cpu.h
> > @@ -678,7 +678,9 @@ typedef enum FeatureWord {
> >      FEAT_7_1_EDX,       /* CPUID[EAX=7,ECX=1].EDX */
> >      FEAT_7_2_EDX,       /* CPUID[EAX=7,ECX=2].EDX */
> >      FEAT_24_0_EBX,      /* CPUID[EAX=0x24,ECX=0].EBX */
> > +    FEAT_RDT_F_0_EBX,  /* CPUID[EAX=0xf,ECX=0].EBX (RDT CMT/MBM) */
> >      FEAT_RDT_F_0_EDX,  /* CPUID[EAX=0xf,ECX=0].EDX (RDT CMT/MBM) */
> > +    FEAT_RDT_10_0_EBX,  /* CPUID[EAX=0x10,ECX=0].EBX (RDT CAT/MBA) */
> >      FEATURE_WORDS,
> >  } FeatureWord;
> >
> > --
> > 2.47.1.613.gc27f4b7a9f-goog
>