On Wed, Jun 13, 2018 at 09:18:23PM -0400, Babu Moger wrote:
> Enable TOPOEXT feature on EPYC CPU. This is required to support
> hyperthreading on VM guests. Also extend xlevel to 0x8000001E.
>
> Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
> ---
> target/i386/cpu.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index 86fb1a4..2eb26da 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -2554,7 +2554,8 @@ static X86CPUDefinition builtin_x86_defs[] = {
> .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_CR8LEG | CPUID_EXT3_SVM | CPUID_EXT3_LAHF_LM |
> + CPUID_EXT3_TOPOEXT,
> .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 |
> @@ -2599,7 +2600,8 @@ static X86CPUDefinition builtin_x86_defs[] = {
> .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_CR8LEG | CPUID_EXT3_SVM | CPUID_EXT3_LAHF_LM |
> + CPUID_EXT3_TOPOEXT,
> .features[FEAT_8000_0008_EBX] =
> CPUID_8000_0008_EBX_IBPB,
> .features[FEAT_7_0_EBX] =
This part is OK, but it requires patch 3/6 to be included in the
same patch.
> @@ -4667,6 +4669,11 @@ static void x86_cpu_expand_features(X86CPU *cpu, Error **errp)
> x86_cpu_adjust_level(cpu, &env->cpuid_min_xlevel, 0x8000000A);
> }
>
> + /* TOPOEXT feature requires 0x8000001E */
> + if (env->features[FEAT_8000_0001_ECX] & CPUID_EXT3_TOPOEXT) {
> + x86_cpu_adjust_level(cpu, &env->cpuid_min_xlevel, 0x8000001E);
> + }
This part needs to be done more carefully to avoid breaking
compatibility. "-machine pc-q35-2.12 -cpu Opteron_G5,+topoext"
currently results in xlevel=0x8000001A, and this must not change.
I suggest just changing setting .xlevel=0x8000001E on EPYC at
builtin_x86_defs[1], and worry about automatically increasing
xlevel later.
(If you change EPYC.xlevel in builtin_x86_defs, don't forget to
set EPYC.xlevel=0x8000000A on PC_COMPAT_2_12)
--
Eduardo
