> -----Original Message----- > From: Eduardo Habkost [mailto:ehabkost@xxxxxxxxxx] > Sent: Thursday, June 14, 2018 1:40 PM > To: Moger, Babu <Babu.Moger@xxxxxxx> > Cc: mst@xxxxxxxxxx; marcel.apfelbaum@xxxxxxxxx; pbonzini@xxxxxxxxxx; > rth@xxxxxxxxxxx; mtosatti@xxxxxxxxxx; qemu-devel@xxxxxxxxxx; > kvm@xxxxxxxxxxxxxxx; kash@xxxxxxxxxxxxxx; geoff@xxxxxxxxxxxxxxx > Subject: Re: [PATCH v14 2/6] i386: Enable TOPOEXT feature on AMD EPYC > CPU > > 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. Ok. Sure. > > > @@ -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. Ok. > > I suggest just changing setting .xlevel=0x8000001E on EPYC at > builtin_x86_defs[1], and worry about automatically increasing > xlevel later. Ok. > > (If you change EPYC.xlevel in builtin_x86_defs, don't forget to > set EPYC.xlevel=0x8000000A on PC_COMPAT_2_12) Sure. > > -- > Eduardo
