Enabling Hyper-V emulation for a Windows VM is a tiring experience as it requires listing all currently supported enlightenments ("hv-*" CPU features) explicitly. We do have 'hv-passthrough' mode enabling everything but it can't be used in production as it prevents migration.
Introduce a simple 'hv-default=on' CPU flag enabling all currently supported Hyper-V enlightenments. Later, when new enlightenments get implemented, compat_props mechanism will be used to disable them for legacy machine types, this will keep 'hv-default=on' configurations migratable. Signed-off-by: Vitaly Kuznetsov <vkuzn...@redhat.com> --- docs/hyperv.txt | 18 ++++++++++++++--- target/i386/cpu.c | 50 +++++++++++++++++++++++++++++++++++++++++++++-- target/i386/cpu.h | 3 +++ 3 files changed, 66 insertions(+), 5 deletions(-) diff --git a/docs/hyperv.txt b/docs/hyperv.txt index 5df00da54fc4..0a15cf026017 100644 --- a/docs/hyperv.txt +++ b/docs/hyperv.txt @@ -17,10 +17,22 @@ compatible hypervisor and use Hyper-V specific features. 2. Setup ========= -No Hyper-V enlightenments are enabled by default by either KVM or QEMU. In -QEMU, individual enlightenments can be enabled through CPU flags, e.g: +The default set of currently supported Hyper-V enlightenments (consisting of all +currently supported enlightenments except for 'hv-evmcs' which can only be +enabled on VMX enabled guests) can be enabled by specifying 'hv-default=on' CPU +flag: - qemu-system-x86_64 --enable-kvm --cpu host,hv_relaxed,hv_vpindex,hv_time, ... + qemu-system-x86_64 --enable-kvm --cpu host,hv-default ... + +Alternatively, it is possible to do fine-grained enablement through CPU flags, +e.g: + + qemu-system-x86_64 --enable-kvm --cpu host,hv-relaxed,hv-vpindex,hv-time ... + +It is also possible to disable individual enlightenments from the default list, +this can be used for debugging purposes: + + qemu-system-x86_64 --enable-kvm --cpu host,hv-default=on,hv-evmcs=off ... Sometimes there are dependencies between enlightenments, QEMU is supposed to check that the supplied configuration is sane. diff --git a/target/i386/cpu.c b/target/i386/cpu.c index dd639dd06784..14f566cfde57 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -4658,6 +4658,25 @@ static void x86_cpuid_set_tsc_freq(Object *obj, Visitor *v, const char *name, cpu->env.tsc_khz = cpu->env.user_tsc_khz = value / 1000; } +static bool x86_hv_default_get(Object *obj, Error **errp) +{ + X86CPU *cpu = X86_CPU(obj); + + return cpu->hyperv_default; +} + +static void x86_hv_default_set(Object *obj, bool value, Error **errp) +{ + X86CPU *cpu = X86_CPU(obj); + + cpu->hyperv_default = value; + + /* hv-default overrides everything with the default set */ + if (value) { + cpu->hyperv_features = cpu->hyperv_default_features; + } +} + /* 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, @@ -6563,10 +6582,16 @@ static void x86_cpu_filter_features(X86CPU *cpu, bool verbose) } } -static void x86_cpu_hyperv_realize(X86CPU *cpu) +static void x86_cpu_hyperv_realize(X86CPU *cpu, Error **errp) { size_t len; + if (cpu->hyperv_passthrough && cpu->hyperv_default) { + error_setg(errp, + "'hv-default' and 'hv-paththrough' are mutually exclusive"); + return; + } + /* Hyper-V vendor id */ if (!cpu->hyperv_vendor) { object_property_set_str(OBJECT(cpu), "hv-vendor-id", "Microsoft Hv", @@ -6768,7 +6793,10 @@ static void x86_cpu_realizefn(DeviceState *dev, Error **errp) } /* Process Hyper-V enlightenments */ - x86_cpu_hyperv_realize(cpu); + x86_cpu_hyperv_realize(cpu, &local_err); + if (local_err) { + goto out; + } cpu_exec_realizefn(cs, &local_err); if (local_err != NULL) { @@ -7063,6 +7091,20 @@ static void x86_cpu_initfn(Object *obj) if (xcc->model) { x86_cpu_load_model(cpu, xcc->model); } + + /* + * Hyper-V features enabled with 'hv-default=on' + * TODO: add 'HYPERV_FEAT_EVMCS' to the list. Enlightened VMCS can only + * be enabled for VMX enabled guests but here it can't be checked. + */ + cpu->hyperv_default_features = BIT(HYPERV_FEAT_RELAXED) | + BIT(HYPERV_FEAT_VAPIC) | BIT(HYPERV_FEAT_TIME) | + BIT(HYPERV_FEAT_CRASH) | BIT(HYPERV_FEAT_RESET) | + BIT(HYPERV_FEAT_VPINDEX) | BIT(HYPERV_FEAT_RUNTIME) | + BIT(HYPERV_FEAT_SYNIC) | BIT(HYPERV_FEAT_STIMER) | + BIT(HYPERV_FEAT_FREQUENCIES) | BIT(HYPERV_FEAT_REENLIGHTENMENT) | + BIT(HYPERV_FEAT_TLBFLUSH) | BIT(HYPERV_FEAT_IPI) | + BIT(HYPERV_FEAT_STIMER_DIRECT); } static int64_t x86_cpu_get_arch_id(CPUState *cs) @@ -7389,6 +7431,10 @@ static void x86_cpu_common_class_init(ObjectClass *oc, void *data) x86_cpu_get_crash_info_qom, NULL, NULL, NULL); #endif + object_class_property_add_bool(oc, "hv-default", + x86_hv_default_get, + x86_hv_default_set); + for (w = 0; w < FEATURE_WORDS; w++) { int bitnr; for (bitnr = 0; bitnr < 64; bitnr++) { diff --git a/target/i386/cpu.h b/target/i386/cpu.h index 265e552746e7..f014f1a89f89 100644 --- a/target/i386/cpu.h +++ b/target/i386/cpu.h @@ -1673,6 +1673,9 @@ struct X86CPU { bool hyperv_synic_kvm_only; uint64_t hyperv_features; bool hyperv_passthrough; + /* 'hv-default' enablement */ + uint64_t hyperv_default_features; + bool hyperv_default; OnOffAuto hyperv_no_nonarch_cs; uint32_t hyperv_vendor_id[3]; uint32_t hyperv_interface_id[4]; -- 2.29.2