@@ -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.
@@ -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++) {
@@ -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];
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 <vkuznets@redhat.com> --- docs/hyperv.txt | 18 ++++++++++++++--- target/i386/cpu.c | 50 +++++++++++++++++++++++++++++++++++++++++++++-- target/i386/cpu.h | 3 +++ 3 files changed, 66 insertions(+), 5 deletions(-)