> -----Original Message----- > From: kvm-owner@xxxxxxxxxxxxxxx [mailto:kvm-owner@xxxxxxxxxxxxxxx] > On Behalf Of Eduardo Habkost > Sent: Monday, June 11, 2018 3:52 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 v13 4/5] i386: Verify and enable topoext feature if > supported > > On Fri, Jun 08, 2018 at 06:56:20PM -0400, Babu Moger wrote: > > If the CPU model supports topoext feature, enabled the > > feature automatically if it can be supported. > > > > Signed-off-by: Babu Moger <babu.moger@xxxxxxx> > > --- > > target/i386/cpu.c | 40 ++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 40 insertions(+) > > > > diff --git a/target/i386/cpu.c b/target/i386/cpu.c > > index 4dd9a82..88bc73d 100644 > > --- a/target/i386/cpu.c > > +++ b/target/i386/cpu.c > > @@ -4763,6 +4763,33 @@ static int x86_cpu_filter_features(X86CPU *cpu) > > #define IS_AMD_CPU(env) ((env)->cpuid_vendor1 == > CPUID_VENDOR_AMD_1 && \ > > (env)->cpuid_vendor2 == CPUID_VENDOR_AMD_2 && \ > > (env)->cpuid_vendor3 == CPUID_VENDOR_AMD_3) > > +/* > > + * Check if we can support this topology > > + * Fail if number of cores are beyond the supported config > > + * or nr_threads is more than 2 > > + */ > > +static int topology_supports_topoext(int nr_cores, int nr_threads, > > + Error **errp) > > +{ > > + if (nr_cores > (MAX_CORES_IN_NODE * MAX_NODES_PER_SOCKET)) { > > + error_setg(errp, "TOPOEXT unsupported with %d cores per socket", > > + nr_cores); > > + error_append_hint(errp, "TOPOEXT supports only up to %d cores > per" > > + " socket\n", > > + (MAX_CORES_IN_NODE * MAX_NODES_PER_SOCKET)); > > + return false; > > + } > > + > > + if (nr_threads > 2) { > > + error_setg(errp, "TOPOEXT unsupported with %d threads per core", > > + nr_threads); > > + error_append_hint(errp, "TOPOEXT supports only up to 2 threads" > > + " per core\n"); > > + return false; > > + } > > + return true; > > +} > > + > > static void x86_cpu_realizefn(DeviceState *dev, Error **errp) > > { > > CPUState *cs = CPU(dev); > > @@ -4953,6 +4980,19 @@ static void x86_cpu_realizefn(DeviceState *dev, > Error **errp) > > > > qemu_init_vcpu(cs); > > > > + if (cpu->auto_topoext && > > + !(env->user_features[FEAT_8000_0001_ECX] & > CPUID_EXT3_TOPOEXT)) { > > + if (cs->nr_cores <= (MAX_CORES_IN_NODE * > MAX_NODES_PER_SOCKET) && > > + (cs->nr_threads <= 2)) { > > This duplicates the logic from topology_supports_topoext(). Why > not just call > topology_supports_topoext(cs->nr_cores, cs->nr_threads, NULL) > here? Ok. Will do it. > > > + env->features[FEAT_8000_0001_ECX] |= CPUID_EXT3_TOPOEXT; > > + } > > + } > > + > > + if ((env->features[FEAT_8000_0001_ECX] & CPUID_EXT3_TOPOEXT) && > > + !topology_supports_topoext(cs->nr_cores, cs->nr_threads, errp)) { > > + return; > > + } > > + > > /* Only Intel CPUs support hyperthreading. Even though QEMU fixes this > > * issue by adjusting CPUID_0000_0001_EBX and CPUID_8000_0008_ECX > > * based on inputs (sockets,cores,threads), it is still better to gives > > -- > > 1.8.3.1 > > > > -- > Eduardo
