Re: [PATCH v2] i386: Add the support for AMD EPYC 3rd generation processors

[Babu Moger <babu.moger@amd.com>]

Hi Pankaj,

On 2/23/21 10:32 AM, Pankaj Gupta wrote:
> Hello Babu,
> 
> Have below doubt about exposed CPU flags between EPYC-Rome & EPYC-Milan family.
> Please see below.
> 
>> Adds the support for AMD 3rd generation processors. The model
>> display for the new processor will be EPYC-Milan.
>>
>> Adds the following new feature bits on top of the feature bits from
>> the first and second generation EPYC models.
>>
>> pcid          : Process context identifiers support
>> ibrs          : Indirect Branch Restricted Speculation
>> ssbd          : Speculative Store Bypass Disable
>> erms          : Enhanced REP MOVSB/STOSB support
>> fsrm          : Fast Short REP MOVSB support
>> invpcid       : Invalidate processor context ID
>> pku           : Protection keys support
>> svme-addr-chk : SVM instructions address check for #GP handling
>>
>> Depends on the following kernel commits:
>> 14c2bf81fcd2 ("KVM: SVM: Fix #GP handling for doubly-nested virtualization")
>> 3b9c723ed7cf ("KVM: SVM: Add support for SVM instruction address check change")
>> 4aa2691dcbd3 ("8ce1c461188799d863398dd2865d KVM: x86: Factor out x86 instruction emulation with decoding")
>> 4407a797e941 ("KVM: SVM: Enable INVPCID feature on AMD")
>> 9715092f8d7e ("KVM: X86: Move handling of INVPCID types to x86")
>> 3f3393b3ce38 ("KVM: X86: Rename and move the function vmx_handle_memory_failure to x86.c")
>> 830bd71f2c06 ("KVM: SVM: Remove set_cr_intercept, clr_cr_intercept and is_cr_intercept")
>> 4c44e8d6c193 ("KVM: SVM: Add new intercept word in vmcb_control_area")
>> c62e2e94b9d4 ("KVM: SVM: Modify 64 bit intercept field to two 32 bit vectors")
>> 9780d51dc2af ("KVM: SVM: Modify intercept_exceptions to generic intercepts")
>> 30abaa88382c ("KVM: SVM: Change intercept_dr to generic intercepts")
>> 03bfeeb988a9 ("KVM: SVM: Change intercept_cr to generic intercepts")
>> c45ad7229d13 ("KVM: SVM: Introduce vmcb_(set_intercept/clr_intercept/_is_intercept)")
>> a90c1ed9f11d ("(pcid) KVM: nSVM: Remove unused field")
>> fa44b82eb831 ("KVM: x86: Move MPK feature detection to common code")
>> 38f3e775e9c2 ("x86/Kconfig: Update config and kernel doc for MPK feature on AMD")
>> 37486135d3a7 ("KVM: x86: Fix pkru save/restore when guest CR4.PKE=0, move it to x86.c")
>>
>> Signed-off-by: Babu Moger <babu.moger@amd.com>
>> ---
>> v2: Added svme-addr-chk. Also added all the dependent kernel commits in the log.
>>
>> v1: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fqemu-devel%2F161133338780.27536.17735339269843944966.stgit%40bmoger-ubuntu%2F&amp;data=04%7C01%7Cbabu.moger%40amd.com%7C4cdb8e4513444faf227d08d8d818b23b%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637496947884399665%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=DepdBnCEp%2By069GaEmWnhETZ8saVkV9E8cExtzIyVLk%3D&amp;reserved=0
>>
>>  target/i386/cpu.c |  107 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>>  target/i386/cpu.h |    4 ++
>>  2 files changed, 110 insertions(+), 1 deletion(-)
>>
>> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
>> index 9c3d2d60b7..24db7ed892 100644
>> --- a/target/i386/cpu.c
>> +++ b/target/i386/cpu.c
>> @@ -1033,7 +1033,7 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
>>              "clzero", NULL, "xsaveerptr", NULL,
>>              NULL, NULL, NULL, NULL,
>>              NULL, "wbnoinvd", NULL, NULL,
>> -            "ibpb", NULL, NULL, "amd-stibp",
>> +            "ibpb", NULL, "ibrs", "amd-stibp",
>>              NULL, NULL, NULL, NULL,
>>              NULL, NULL, NULL, NULL,
>>              "amd-ssbd", "virt-ssbd", "amd-no-ssb", NULL,
>> @@ -1798,6 +1798,56 @@ static CPUCaches epyc_rome_cache_info = {
>>      },
>>  };
>>
>> +static CPUCaches epyc_milan_cache_info = {
>> +    .l1d_cache = &(CPUCacheInfo) {
>> +        .type = DATA_CACHE,
>> +        .level = 1,
>> +        .size = 32 * KiB,
>> +        .line_size = 64,
>> +        .associativity = 8,
>> +        .partitions = 1,
>> +        .sets = 64,
>> +        .lines_per_tag = 1,
>> +        .self_init = 1,
>> +        .no_invd_sharing = true,
>> +    },
>> +    .l1i_cache = &(CPUCacheInfo) {
>> +        .type = INSTRUCTION_CACHE,
>> +        .level = 1,
>> +        .size = 32 * KiB,
>> +        .line_size = 64,
>> +        .associativity = 8,
>> +        .partitions = 1,
>> +        .sets = 64,
>> +        .lines_per_tag = 1,
>> +        .self_init = 1,
>> +        .no_invd_sharing = true,
>> +    },
>> +    .l2_cache = &(CPUCacheInfo) {
>> +        .type = UNIFIED_CACHE,
>> +        .level = 2,
>> +        .size = 512 * KiB,
>> +        .line_size = 64,
>> +        .associativity = 8,
>> +        .partitions = 1,
>> +        .sets = 1024,
>> +        .lines_per_tag = 1,
>> +    },
>> +    .l3_cache = &(CPUCacheInfo) {
>> +        .type = UNIFIED_CACHE,
>> +        .level = 3,
>> +        .size = 32 * MiB,
>> +        .line_size = 64,
>> +        .associativity = 16,
>> +        .partitions = 1,
>> +        .sets = 32768,
>> +        .lines_per_tag = 1,
>> +        .self_init = true,
>> +        .inclusive = true,
>> +        .complex_indexing = true,
>> +    },
>> +};
>> +
>>  /* The following VMX features are not supported by KVM and are left out in the
>>   * CPU definitions:
>>   *
>> @@ -4130,6 +4180,61 @@ static X86CPUDefinition builtin_x86_defs[] = {
>>          .model_id = "AMD EPYC-Rome Processor",
>>          .cache_info = &epyc_rome_cache_info,
>>      },
>> +    {
>> +        .name = "EPYC-Milan",
>> +        .level = 0xd,
>> +        .vendor = CPUID_VENDOR_AMD,
>> +        .family = 25,
>> +        .model = 1,
>> +        .stepping = 1,
>> +        .features[FEAT_1_EDX] =
>> +            CPUID_SSE2 | CPUID_SSE | CPUID_FXSR | CPUID_MMX | CPUID_CLFLUSH |
>> +            CPUID_PSE36 | CPUID_PAT | CPUID_CMOV | CPUID_MCA | CPUID_PGE |
>> +            CPUID_MTRR | CPUID_SEP | CPUID_APIC | CPUID_CX8 | CPUID_MCE |
>> +            CPUID_PAE | CPUID_MSR | CPUID_TSC | CPUID_PSE | CPUID_DE |
>> +            CPUID_VME | CPUID_FP87,
>> +        .features[FEAT_1_ECX] =
>> +            CPUID_EXT_RDRAND | CPUID_EXT_F16C | CPUID_EXT_AVX |
>> +            CPUID_EXT_XSAVE | CPUID_EXT_AES |  CPUID_EXT_POPCNT |
>> +            CPUID_EXT_MOVBE | CPUID_EXT_SSE42 | CPUID_EXT_SSE41 |
>> +            CPUID_EXT_CX16 | CPUID_EXT_FMA | CPUID_EXT_SSSE3 |
>> +            CPUID_EXT_MONITOR | CPUID_EXT_PCLMULQDQ | CPUID_EXT_SSE3 |
>> +            CPUID_EXT_PCID,
>> +        .features[FEAT_8000_0001_EDX] =
>> +            CPUID_EXT2_LM | CPUID_EXT2_RDTSCP | CPUID_EXT2_PDPE1GB |
>> +            CPUID_EXT2_FFXSR | CPUID_EXT2_MMXEXT | CPUID_EXT2_NX |
>> +            CPUID_EXT2_SYSCALL,
>> +        .features[FEAT_8000_0001_ECX] =
>> +            CPUID_EXT3_OSVW | CPUID_EXT3_3DNOWPREFETCH |
>> +            CPUID_EXT3_MISALIGNSSE | CPUID_EXT3_SSE4A | CPUID_EXT3_ABM |
>> +            CPUID_EXT3_CR8LEG | CPUID_EXT3_SVM | CPUID_EXT3_LAHF_LM |
>> +            CPUID_EXT3_TOPOEXT | CPUID_EXT3_PERFCORE,
>> +        .features[FEAT_8000_0008_EBX] =
>> +            CPUID_8000_0008_EBX_CLZERO | CPUID_8000_0008_EBX_XSAVEERPTR |
>> +            CPUID_8000_0008_EBX_WBNOINVD | CPUID_8000_0008_EBX_IBPB |
>> +            CPUID_8000_0008_EBX_IBRS | CPUID_8000_0008_EBX_STIBP |
>> +            CPUID_8000_0008_EBX_AMD_SSBD,
> 
> Don't have SSBD flag exposed in default EPYC-Rome CPU configuration?
> Is there any reason for this?
> Or do we need to explicitly add it?

I think we missed it when we added EPYC-Rome model. I was going to add it
sometime soon. As you know users can still add it with "+ssbd" if required.
Thanks
Babu

> 
> Thanks,
> Pankaj
> 
>> +        .features[FEAT_7_0_EBX] =
>> +            CPUID_7_0_EBX_FSGSBASE | CPUID_7_0_EBX_BMI1 | CPUID_7_0_EBX_AVX2 |
>> +            CPUID_7_0_EBX_SMEP | CPUID_7_0_EBX_BMI2 | CPUID_7_0_EBX_RDSEED |
>> +            CPUID_7_0_EBX_ADX | CPUID_7_0_EBX_SMAP | CPUID_7_0_EBX_CLFLUSHOPT |
>> +            CPUID_7_0_EBX_SHA_NI | CPUID_7_0_EBX_CLWB | CPUID_7_0_EBX_ERMS |
>> +            CPUID_7_0_EBX_INVPCID,
>> +        .features[FEAT_7_0_ECX] =
>> +            CPUID_7_0_ECX_UMIP | CPUID_7_0_ECX_RDPID | CPUID_7_0_ECX_PKU,
>> +        .features[FEAT_7_0_EDX] =
>> +            CPUID_7_0_EDX_FSRM,
>> +        .features[FEAT_XSAVE] =
>> +            CPUID_XSAVE_XSAVEOPT | CPUID_XSAVE_XSAVEC |
>> +            CPUID_XSAVE_XGETBV1 | CPUID_XSAVE_XSAVES,
>> +        .features[FEAT_6_EAX] =
>> +            CPUID_6_EAX_ARAT,
>> +        .features[FEAT_SVM] =
>> +            CPUID_SVM_NPT | CPUID_SVM_NRIPSAVE | CPUID_SVM_SVME_ADDR_CHK,
>> +        .xlevel = 0x8000001E,
>> +        .model_id = "AMD EPYC-Milan Processor",
>> +        .cache_info = &epyc_milan_cache_info,
>> +    },
>>  };
>>
>>  /* KVM-specific features that are automatically added/removed
>> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
>> index 8d599bb5b8..888c3a59e2 100644
>> --- a/target/i386/cpu.h
>> +++ b/target/i386/cpu.h
>> @@ -816,8 +816,12 @@ typedef uint64_t FeatureWordArray[FEATURE_WORDS];
>>  #define CPUID_8000_0008_EBX_WBNOINVD    (1U << 9)
>>  /* Indirect Branch Prediction Barrier */
>>  #define CPUID_8000_0008_EBX_IBPB        (1U << 12)
>> +/* Indirect Branch Restricted Speculation */
>> +#define CPUID_8000_0008_EBX_IBRS        (1U << 14)
>>  /* Single Thread Indirect Branch Predictors */
>>  #define CPUID_8000_0008_EBX_STIBP       (1U << 15)
>> +/* Speculative Store Bypass Disable */
>> +#define CPUID_8000_0008_EBX_AMD_SSBD    (1U << 24)
>>
>>  #define CPUID_XSAVE_XSAVEOPT   (1U << 0)
>>  #define CPUID_XSAVE_XSAVEC     (1U << 1)
>>
>>