| Message ID | 1408566612-10367-1-git-send-email-ehabkost@redhat.com |
|---|---|
| State | New |
| Headers | show |
Am 04.09.2014 17:19, schrieb Eduardo Habkost: > On Tue, Sep 02, 2014 at 10:08:56AM -0500, Michael Roth wrote: >> Quoting Eduardo Habkost (2014-08-21 15:14:38) >>> Forgot to add qemu-devel to "To:". Adding it. >>> >>> On Wed, Aug 20, 2014 at 05:30:12PM -0300, Eduardo Habkost wrote: >>>> When the "migratable" property was implemented, the behavior was tested >>>> by changing the default on the code, but actually using the option on >>>> the command-line (e.g. "-cpu host,migratable=false") doesn't work as >>>> expected. This is a regression for a common use case of "-cpu host", >>>> which is to enable features that are supported by the host CPU + kernel >>>> before feature-specific code is added to QEMU. >>>> >>>> Fix this by initializing the feature words for "-cpu host" on >>>> x86_cpu_parse_featurestr(), right after parsing the CPU options. >>>> >>>> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> >> >> Ping for stable 2.1.1, freeze is Wednesday. >> >> Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com> > > Ping? Who can help me get this applied? > > I was expecting to need to argue to get this considered as -stable > material, but not to have trouble getting it applied to master... Thanks, applied to qom-cpu: https://github.com/afaerber/qemu-cpu/commits/qom-cpu Andreas
diff --git a/target-i386/cpu-qom.h b/target-i386/cpu-qom.h index 71a1b97..7755466 100644 --- a/target-i386/cpu-qom.h +++ b/target-i386/cpu-qom.h @@ -92,6 +92,7 @@ typedef struct X86CPU { bool enforce_cpuid; bool expose_kvm; bool migratable; + bool host_features; /* if true the CPUID code directly forward host cache leaves to the guest */ bool cache_info_passthrough; diff --git a/target-i386/cpu.c b/target-i386/cpu.c index 6d008ab..c0f8efc 100644 --- a/target-i386/cpu.c +++ b/target-i386/cpu.c @@ -1318,18 +1318,18 @@ static void host_x86_cpu_initfn(Object *obj) X86CPU *cpu = X86_CPU(obj); CPUX86State *env = &cpu->env; KVMState *s = kvm_state; - FeatureWord w; assert(kvm_enabled()); + /* We can't fill the features array here because we don't know yet if + * "migratable" is true or false. + */ + cpu->host_features = true; + env->cpuid_level = kvm_arch_get_supported_cpuid(s, 0x0, 0, R_EAX); env->cpuid_xlevel = kvm_arch_get_supported_cpuid(s, 0x80000000, 0, R_EAX); env->cpuid_xlevel2 = kvm_arch_get_supported_cpuid(s, 0xC0000000, 0, R_EAX); - for (w = 0; w < FEATURE_WORDS; w++) { - env->features[w] = - x86_cpu_get_supported_feature_word(w, cpu->migratable); - } object_property_set_bool(OBJECT(cpu), true, "pmu", &error_abort); } @@ -1828,6 +1828,13 @@ static void x86_cpu_parse_featurestr(CPUState *cs, char *features, featurestr = strtok(NULL, ","); } + if (cpu->host_features) { + for (w = 0; w < FEATURE_WORDS; w++) { + env->features[w] = + x86_cpu_get_supported_feature_word(w, cpu->migratable); + } + } + for (w = 0; w < FEATURE_WORDS; w++) { env->features[w] |= plus_features[w]; env->features[w] &= ~minus_features[w];
When the "migratable" property was implemented, the behavior was tested by changing the default on the code, but actually using the option on the command-line (e.g. "-cpu host,migratable=false") doesn't work as expected. This is a regression for a common use case of "-cpu host", which is to enable features that are supported by the host CPU + kernel before feature-specific code is added to QEMU. Fix this by initializing the feature words for "-cpu host" on x86_cpu_parse_featurestr(), right after parsing the CPU options. Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> --- I was considering a more complex (but less hacky) fix, by introducing an enum FeatureBit { OFF, ON, HOST }, making FeatureWord a 32-element FeatureBit array, and initializing the actual feature bits on x86_cpu_realizefn(). But as this is a patch for qemu-stable, I kept the fix as simple as possible. --- target-i386/cpu-qom.h | 1 + target-i386/cpu.c | 17 ++++++++++++----- 2 files changed, 13 insertions(+), 5 deletions(-)