On Fri, Oct 26, 2018 at 11:01:25AM +0800, Robert Hoo wrote: > On Wed, 2018-10-24 at 07:06 -0300, Eduardo Habkost wrote: > > On Mon, Oct 15, 2018 at 12:47:25PM +0800, Robert Hoo wrote: > > > Note RSBA is specially treated -- no matter host support it or not, > > > qemu > > > pretends it is supported. > > > > > > Signed-off-by: Robert Hoo <robert...@linux.intel.com> > > > > I am now wondering what else we need to be able to remove > > CPUID_7_0_EDX_ARCH_CAPABILITIES from > > feature_word_info[FEAT_7_0_EDX].unmigratable_flags. > > > > This series is necessary for that, be I think we still can't let > > the VM be migrated if arch-capabilities is enabled and we're > > running on a host that doesn't have MSR_IA32_ARCH_CAPABILITIES on > > kvm_feature_msrs. > > > > Reviewed-by: Eduardo Habkost <ehabk...@redhat.com> > > > > > --- > > > target/i386/cpu.c | 31 ++++++++++++++++++++++++++++++- > > > target/i386/cpu.h | 8 ++++++++ > > > target/i386/kvm.c | 11 +++++++++++ > > > 3 files changed, 49 insertions(+), 1 deletion(-) > > > > [...] > > > > > > typedef struct X86RegisterInfo32 { > > > @@ -3696,7 +3717,15 @@ static uint32_t > > > x86_cpu_get_supported_feature_word(FeatureWord w, > > > wi- > > > >cpuid.reg); > > > break; > > > case MSR_FEATURE_WORD: > > > - r = kvm_arch_get_supported_msr_feature(kvm_state, wi- > > > >msr.index); > > > + /* Special case: > > > + * No matter host status, IA32_ARCH_CAPABILITIES.RSBA > > > [bit 2] > > > + * is always supported in guest. > > > + */ > > > + if (wi->msr.index == MSR_IA32_ARCH_CAPABILITIES) { > > > + r = MSR_ARCH_CAP_RSBA; > > > + } > > > + r |= kvm_arch_get_supported_msr_feature(kvm_state, > > > + wi->msr.index); > > > break; > After I add the filtering out MSR feature, whose CPUID dependency fails > , in x86_cpu_filter_features(), 1 issue comes out here: > > If running on an old platform that doesn't have ARCH_CAPABILITIES MSR, > but we still pretends it here, then qemu will always print out > "warning: host doesn't support requested feature: MSR(10AH).rsba [bit > 2]", with -cpu 'host', which does not look comfortable. > How about remove this hunk for now? leave it to when we fully decide > how to handle ARCH_CAPABILITIES live-migration safely.
I will remove that hunk in x86-next, thanks for noting! -- Eduardo