From ced1be70e26a5a537e2da52d41ce6dae6c686d8b Mon Sep 17 00:00:00 2001 From: "Moger, Babu" Date: Thu, 30 Apr 2020 06:47:14 -0400 Subject: [PATCH] i386: Add missing cpu feature bits in EPYC model Adds the following missing CPUID bits: perfctr-core : core performance counter extensions support. Enables the VM to use extended performance counter support. It enables six programmable counters instead of 4 counters. clzero : instruction zeroes out the 64 byte cache line specified in RAX. xsaveerptr : XSAVE, XSAVE, FXSAVEOPT, XSAVEC, XSAVES always save error pointers and FXRSTOR, XRSTOR, XRSTORS always restore error pointers. ibpb : Indirect Branch Prediction Barrie. xsaves : XSAVES, XRSTORS and IA32_XSS supported. Depends on following kernel commits: 40bc47b08b6e ("kvm: x86: Enumerate support for CLZERO instruction") 504ce1954fba ("KVM: x86: Expose XSAVEERPTR to the guest") 52297436199d ("kvm: svm: Update svm_xsaves_supported") These new features will be added in EPYC-v3. The -cpu help output after the change. x86 EPYC-v1 AMD EPYC Processor x86 EPYC-v2 AMD EPYC Processor (with IBPB) x86 EPYC-v3 AMD EPYC Processor Backports commit a16e8dbc043720abcb37fc7dca313e720b4e0f0c from qemu --- qemu/target/i386/cpu.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/qemu/target/i386/cpu.c b/qemu/target/i386/cpu.c index 9fa0f354..5bb07719 100644 --- a/qemu/target/i386/cpu.c +++ b/qemu/target/i386/cpu.c @@ -3721,10 +3721,6 @@ static X86CPUDefinition builtin_x86_defs[] = { 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, - /* Missing: XSAVES (not supported by some Linux versions, - * including v4.1 to v4.12). - * KVM doesn't yet expose any XSAVES state save component. - */ .features[FEAT_XSAVE] = CPUID_XSAVE_XSAVEOPT | CPUID_XSAVE_XSAVEC | CPUID_XSAVE_XGETBV1, @@ -3747,6 +3743,19 @@ static X86CPUDefinition builtin_x86_defs[] = { { /* end of list */ } } }, + { + .version = 3, + .props = (PropValue[]) { + { "ibpb", "on" }, + { "perfctr-core", "on" }, + { "clzero", "on" }, + { "xsaveerptr", "on" }, + { "xsaves", "on" }, + { "model-id", + "AMD EPYC Processor" }, + { /* end of list */ } + } + }, { /* end of list */ } } },