On Fri, 12 Feb 2021 09:49:46 +0100 Vitaly Kuznetsov <vkuzn...@redhat.com> wrote:
> Igor Mammedov <imamm...@redhat.com> writes: > > > On Wed, 10 Feb 2021 17:40:29 +0100 > > Vitaly Kuznetsov <vkuzn...@redhat.com> wrote: > > > >> Currently, we support 'hv-passthrough,hv-feature=on' enablement, this > >> is supposed to mean "hv-feature is mandatory, don't start without it". Add > >> support for 'hv-passthrough,hv-feature=off' meaning "enable everything > >> supported by the host except for hv-feature". > >> > >> While on it, make 'hv-passthrough' parse semantics in-line with other > >> options in qemu: when specified, it overrides what was previously set with > >> what's supported by the host. This can later be modified with > >> 'hv-feature=on'/ > >> 'hv-feature=off'. > >> > >> Signed-off-by: Vitaly Kuznetsov <vkuzn...@redhat.com> > >> --- > >> target/i386/cpu.c | 28 +++++++++++++++++++++++++++- > >> target/i386/kvm/kvm.c | 4 ++++ > >> 2 files changed, 31 insertions(+), 1 deletion(-) > >> > >> diff --git a/target/i386/cpu.c b/target/i386/cpu.c > >> index e8a004c39d04..f8df2caed779 100644 > >> --- a/target/i386/cpu.c > >> +++ b/target/i386/cpu.c > >> @@ -4725,6 +4725,29 @@ static void x86_hv_stimer_direct_set(Object *obj, > >> bool value, Error **errp) > >> x86_hv_feature_set(obj, value, HYPERV_FEAT_STIMER_DIRECT); > >> } > >> > >> +static bool x86_hv_passthrough_get(Object *obj, Error **errp) > >> +{ > >> + X86CPU *cpu = X86_CPU(obj); > >> + > >> + return cpu->hyperv_passthrough; > >> +} > >> + > >> +static void x86_hv_passthrough_set(Object *obj, bool value, Error **errp) > >> +{ > >> + X86CPU *cpu = X86_CPU(obj); > >> + > >> + cpu->hyperv_passthrough = value; > >> + > >> + /* hv-passthrough overrides everything with what's supported by the > >> host */ > >> + if (value) { > >> + cpu->hyperv_features = 0; > >> + cpu->hyperv_features_on = 0; > >> + cpu->hyperv_features_off = 0; > > > > why do we have _on|_off fields? > > > > You mean 'why do we have them at all' or 'why do we reset them here'? > For the former, we need to distinguish between > 'hv-passthroug,hv-feature=off' and just 'hv-passthrough'; > 'hv-passthrough,hv-evmcs=on' and just 'hv-passthrough'. For the later, that's what I was asking for, eventually I found it being buried in kvm code > I'd like to make the samentics you've asked for: > 'hv-feature,hv-passthrough' == 'hv-passthrough' you essentially you wrote your own hv-foo parser in kvm_hyperv_expand_features(), which is a bit complicated for my taste. With scratch CPU you can simplify and make it easier to read. > (though I still see it as a gotcha for an unprepared user) this way it at least works the same way like any other property. > >> + } > >> + > >> + return; > >> +} > >> + > >> /* Generic getter for "feature-words" and "filtered-features" properties > >> */ > >> static void x86_cpu_get_feature_words(Object *obj, Visitor *v, > >> const char *name, void *opaque, > >> @@ -7281,7 +7304,6 @@ static Property x86_cpu_properties[] = { > >> HYPERV_SPINLOCK_NEVER_NOTIFY), > >> DEFINE_PROP_ON_OFF_AUTO("hv-no-nonarch-coresharing", X86CPU, > >> hyperv_no_nonarch_cs, ON_OFF_AUTO_OFF), > >> - DEFINE_PROP_BOOL("hv-passthrough", X86CPU, hyperv_passthrough, false), > >> > >> DEFINE_PROP_BOOL("check", X86CPU, check_cpuid, true), > >> DEFINE_PROP_BOOL("enforce", X86CPU, enforce_cpuid, false), > >> @@ -7460,6 +7482,10 @@ static void x86_cpu_common_class_init(ObjectClass > >> *oc, void *data) > >> x86_hv_stimer_direct_get, > >> x86_hv_stimer_direct_set); > >> > >> + object_class_property_add_bool(oc, "hv-passthrough", > >> + x86_hv_passthrough_get, > >> + x86_hv_passthrough_set); > >> + > >> for (w = 0; w < FEATURE_WORDS; w++) { > >> int bitnr; > >> for (bitnr = 0; bitnr < 64; bitnr++) { > >> diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c > >> index 30013f0d7cee..fca088d4d3b5 100644 > >> --- a/target/i386/kvm/kvm.c > >> +++ b/target/i386/kvm/kvm.c > >> @@ -1153,6 +1153,10 @@ static int hv_cpuid_check_and_set(CPUState *cs, int > >> feature, Error **errp) > >> return 0; > >> } > >> > >> + if (cpu->hyperv_passthrough && (cpu->hyperv_features_off & > >> BIT(feature))) { > >> + return 0; > >> + } > >> + > >> deps = kvm_hyperv_properties[feature].dependencies; > >> while (deps) { > >> dep_feat = ctz64(deps); > > >