diff mbox series

[RFC,v3,23/23] i386: provide simple 'hyperv=on' option to x86 machine types

Message ID 20201009121842.1938010-24-vkuznets@redhat.com
State New
Headers show
Series i386: KVM: expand Hyper-V features early | expand

Commit Message

Vitaly Kuznetsov Oct. 9, 2020, 12:18 p.m. UTC
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 a 'hv_passthrough' mode enabling
everything but it can't be used in production as it prevents migration.

Introduce a simple 'hyperv=on' option for all x86 machine types enabling
all currently supported Hyper-V enlightenments. Later, when new
enlightenments get implemented, we will be adding them to newer machine
types only (by disabling them for legacy machine types) thus preserving
migration.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 docs/hyperv.txt       |  8 ++++++++
 hw/i386/x86.c         | 30 ++++++++++++++++++++++++++++++
 include/hw/i386/x86.h |  7 +++++++
 target/i386/cpu.c     | 14 ++++++++++++++
 4 files changed, 59 insertions(+)

Comments

Eduardo Habkost Nov. 18, 2020, 10:25 p.m. UTC | #1
On Fri, Oct 09, 2020 at 02:18:42PM +0200, Vitaly Kuznetsov wrote:
> 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 a 'hv_passthrough' mode enabling

> everything but it can't be used in production as it prevents migration.

> 

> Introduce a simple 'hyperv=on' option for all x86 machine types enabling

> all currently supported Hyper-V enlightenments. Later, when new

> enlightenments get implemented, we will be adding them to newer machine

> types only (by disabling them for legacy machine types) thus preserving

> migration.

> 

> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>


This patch seems to be especially useful, and I wonder if we
could make sure this is included before all the rest of the
series.  Especially considering that the KVM changes might take a
while to be merged.

Would you be able to submit this independently from the rest of
the series?  You can add my:

Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>


My only (minor) suggestion is to rename
X86MachineClass.hyperv_features to
X86MachineClass.default_hyperv_features.

> ---

>  docs/hyperv.txt       |  8 ++++++++

>  hw/i386/x86.c         | 30 ++++++++++++++++++++++++++++++

>  include/hw/i386/x86.h |  7 +++++++

>  target/i386/cpu.c     | 14 ++++++++++++++

>  4 files changed, 59 insertions(+)

> 

> diff --git a/docs/hyperv.txt b/docs/hyperv.txt

> index 5df00da54fc4..1a76a07f8417 100644

> --- a/docs/hyperv.txt

> +++ b/docs/hyperv.txt

> @@ -29,6 +29,14 @@ When any set of the Hyper-V enlightenments is enabled, QEMU changes hypervisor

>  identification (CPUID 0x40000000..0x4000000A) to Hyper-V. KVM identification

>  and features are kept in leaves 0x40000100..0x40000101.

>  

> +Hyper-V enlightenments can be enabled in bulk by specifying 'hyperv=on' to an

> +x86 machine type:

> +

> +  qemu-system-x86_64 -machine q35,accel=kvm,kernel-irqchip=split,hyperv=on ...

> +

> +Note, new enlightenments are only added to the latest (in-develompent) machine

> +type, older machine types keep the list of the supported features intact to

> +safeguard migration.

>  

>  3. Existing enlightenments

>  ===========================

> diff --git a/hw/i386/x86.c b/hw/i386/x86.c

> index 3137a2008588..eeecd4e3322f 100644

> --- a/hw/i386/x86.c

> +++ b/hw/i386/x86.c

> @@ -1171,6 +1171,20 @@ static void x86_machine_set_acpi(Object *obj, Visitor *v, const char *name,

>      visit_type_OnOffAuto(v, name, &x86ms->acpi, errp);

>  }

>  

> +static bool x86_machine_get_hyperv(Object *obj, Error **errp)

> +{

> +    X86MachineState *x86ms = X86_MACHINE(obj);

> +

> +    return x86ms->hyperv_enabled;

> +}

> +

> +static void x86_machine_set_hyperv(Object *obj, bool value, Error **errp)

> +{

> +    X86MachineState *x86ms = X86_MACHINE(obj);

> +

> +    x86ms->hyperv_enabled = value;

> +}

> +

>  static void x86_machine_initfn(Object *obj)

>  {

>      X86MachineState *x86ms = X86_MACHINE(obj);

> @@ -1193,6 +1207,16 @@ static void x86_machine_class_init(ObjectClass *oc, void *data)

>      x86mc->save_tsc_khz = true;

>      nc->nmi_monitor_handler = x86_nmi;

>  

> +    /* Hyper-V features enabled with 'hyperv=on' */

> +    x86mc->hyperv_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_EVMCS) | BIT(HYPERV_FEAT_IPI) |

> +        BIT(HYPERV_FEAT_STIMER_DIRECT);

> +

>      object_class_property_add(oc, X86_MACHINE_SMM, "OnOffAuto",

>          x86_machine_get_smm, x86_machine_set_smm,

>          NULL, NULL);

> @@ -1204,6 +1228,12 @@ static void x86_machine_class_init(ObjectClass *oc, void *data)

>          NULL, NULL);

>      object_class_property_set_description(oc, X86_MACHINE_ACPI,

>          "Enable ACPI");

> +

> +    object_class_property_add_bool(oc, X86_MACHINE_HYPERV,

> +        x86_machine_get_hyperv, x86_machine_set_hyperv);

> +

> +    object_class_property_set_description(oc, X86_MACHINE_HYPERV,

> +        "Enable Hyper-V enlightenments");

>  }

>  

>  static const TypeInfo x86_machine_info = {

> diff --git a/include/hw/i386/x86.h b/include/hw/i386/x86.h

> index d5dcf7a07fdc..2b989e5fc49d 100644

> --- a/include/hw/i386/x86.h

> +++ b/include/hw/i386/x86.h

> @@ -38,6 +38,9 @@ struct X86MachineClass {

>      bool save_tsc_khz;

>      /* Enables contiguous-apic-ID mode */

>      bool compat_apic_id_mode;

> +

> +    /* Hyper-V features enabled with 'hyperv=on' */

> +    uint64_t hyperv_features;

>  };

>  

>  struct X86MachineState {

> @@ -70,10 +73,14 @@ struct X86MachineState {

>       * will be translated to MSI messages in the address space.

>       */

>      AddressSpace *ioapic_as;

> +

> +    /* Hyper-V emulation */

> +    bool hyperv_enabled;

>  };

>  

>  #define X86_MACHINE_SMM              "smm"

>  #define X86_MACHINE_ACPI             "acpi"

> +#define X86_MACHINE_HYPERV           "hyperv"

>  

>  #define TYPE_X86_MACHINE   MACHINE_TYPE_NAME("x86")

>  OBJECT_DECLARE_TYPE(X86MachineState, X86MachineClass, X86_MACHINE)

> diff --git a/target/i386/cpu.c b/target/i386/cpu.c

> index 55706c8050fe..d0961c1838ad 100644

> --- a/target/i386/cpu.c

> +++ b/target/i386/cpu.c

> @@ -53,6 +53,7 @@

>  #include "sysemu/tcg.h"

>  #include "hw/qdev-properties.h"

>  #include "hw/i386/topology.h"

> +#include "hw/i386/x86.h"

>  #ifndef CONFIG_USER_ONLY

>  #include "exec/address-spaces.h"

>  #include "hw/i386/apic_internal.h"

> @@ -6409,8 +6410,21 @@ static void x86_cpu_filter_features(X86CPU *cpu, bool verbose)

>  

>  static void x86_cpu_hyperv_realize(X86CPU *cpu)

>  {

> +    X86MachineState *x86ms = X86_MACHINE(qdev_get_machine());

> +    X86MachineClass *x86mc = X86_MACHINE_GET_CLASS(x86ms);

> +    uint64_t feat;

>      size_t len;

>  

> +    if (x86ms->hyperv_enabled) {

> +        feat = x86mc->hyperv_features;

> +        /* Enlightened VMCS is only available on Intel/VMX */

> +        if (!cpu_has_vmx(&cpu->env)) {

> +            feat &= ~BIT(HYPERV_FEAT_EVMCS);

> +        }

> +

> +        cpu->hyperv_features |= feat;

> +    }

> +

>      /* Hyper-V vendor id */

>      if (!cpu->hyperv_vendor) {

>          object_property_set_str(OBJECT(cpu), "hv-vendor-id", "Microsoft Hv",

> -- 

> 2.25.4

> 


-- 
Eduardo
Vitaly Kuznetsov Nov. 19, 2020, 8:52 a.m. UTC | #2
Eduardo Habkost <ehabkost@redhat.com> writes:

> On Fri, Oct 09, 2020 at 02:18:42PM +0200, Vitaly Kuznetsov wrote:

>> 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 a 'hv_passthrough' mode enabling

>> everything but it can't be used in production as it prevents migration.

>> 

>> Introduce a simple 'hyperv=on' option for all x86 machine types enabling

>> all currently supported Hyper-V enlightenments. Later, when new

>> enlightenments get implemented, we will be adding them to newer machine

>> types only (by disabling them for legacy machine types) thus preserving

>> migration.

>> 

>> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>

>

> This patch seems to be especially useful, and I wonder if we

> could make sure this is included before all the rest of the

> series.  Especially considering that the KVM changes might take a

> while to be merged.


The required KVM changes are queued for 5.11 and I was delaying next
submission till then.

>

> Would you be able to submit this independently from the rest of

> the series?  You can add my:

>

> Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>

>

> My only (minor) suggestion is to rename

> X86MachineClass.hyperv_features to

> X86MachineClass.default_hyperv_features.


Sure, will do. I'll probably pick a few small patches from the series
(e.g. the one bringing x86_cpu_hyperv_realize()) to minimize the code
churn in the future.

>

>> ---

>>  docs/hyperv.txt       |  8 ++++++++

>>  hw/i386/x86.c         | 30 ++++++++++++++++++++++++++++++

>>  include/hw/i386/x86.h |  7 +++++++

>>  target/i386/cpu.c     | 14 ++++++++++++++

>>  4 files changed, 59 insertions(+)

>> 

>> diff --git a/docs/hyperv.txt b/docs/hyperv.txt

>> index 5df00da54fc4..1a76a07f8417 100644

>> --- a/docs/hyperv.txt

>> +++ b/docs/hyperv.txt

>> @@ -29,6 +29,14 @@ When any set of the Hyper-V enlightenments is enabled, QEMU changes hypervisor

>>  identification (CPUID 0x40000000..0x4000000A) to Hyper-V. KVM identification

>>  and features are kept in leaves 0x40000100..0x40000101.

>>  

>> +Hyper-V enlightenments can be enabled in bulk by specifying 'hyperv=on' to an

>> +x86 machine type:

>> +

>> +  qemu-system-x86_64 -machine q35,accel=kvm,kernel-irqchip=split,hyperv=on ...

>> +

>> +Note, new enlightenments are only added to the latest (in-develompent) machine

>> +type, older machine types keep the list of the supported features intact to

>> +safeguard migration.

>>  

>>  3. Existing enlightenments

>>  ===========================

>> diff --git a/hw/i386/x86.c b/hw/i386/x86.c

>> index 3137a2008588..eeecd4e3322f 100644

>> --- a/hw/i386/x86.c

>> +++ b/hw/i386/x86.c

>> @@ -1171,6 +1171,20 @@ static void x86_machine_set_acpi(Object *obj, Visitor *v, const char *name,

>>      visit_type_OnOffAuto(v, name, &x86ms->acpi, errp);

>>  }

>>  

>> +static bool x86_machine_get_hyperv(Object *obj, Error **errp)

>> +{

>> +    X86MachineState *x86ms = X86_MACHINE(obj);

>> +

>> +    return x86ms->hyperv_enabled;

>> +}

>> +

>> +static void x86_machine_set_hyperv(Object *obj, bool value, Error **errp)

>> +{

>> +    X86MachineState *x86ms = X86_MACHINE(obj);

>> +

>> +    x86ms->hyperv_enabled = value;

>> +}

>> +

>>  static void x86_machine_initfn(Object *obj)

>>  {

>>      X86MachineState *x86ms = X86_MACHINE(obj);

>> @@ -1193,6 +1207,16 @@ static void x86_machine_class_init(ObjectClass *oc, void *data)

>>      x86mc->save_tsc_khz = true;

>>      nc->nmi_monitor_handler = x86_nmi;

>>  

>> +    /* Hyper-V features enabled with 'hyperv=on' */

>> +    x86mc->hyperv_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_EVMCS) | BIT(HYPERV_FEAT_IPI) |

>> +        BIT(HYPERV_FEAT_STIMER_DIRECT);

>> +

>>      object_class_property_add(oc, X86_MACHINE_SMM, "OnOffAuto",

>>          x86_machine_get_smm, x86_machine_set_smm,

>>          NULL, NULL);

>> @@ -1204,6 +1228,12 @@ static void x86_machine_class_init(ObjectClass *oc, void *data)

>>          NULL, NULL);

>>      object_class_property_set_description(oc, X86_MACHINE_ACPI,

>>          "Enable ACPI");

>> +

>> +    object_class_property_add_bool(oc, X86_MACHINE_HYPERV,

>> +        x86_machine_get_hyperv, x86_machine_set_hyperv);

>> +

>> +    object_class_property_set_description(oc, X86_MACHINE_HYPERV,

>> +        "Enable Hyper-V enlightenments");

>>  }

>>  

>>  static const TypeInfo x86_machine_info = {

>> diff --git a/include/hw/i386/x86.h b/include/hw/i386/x86.h

>> index d5dcf7a07fdc..2b989e5fc49d 100644

>> --- a/include/hw/i386/x86.h

>> +++ b/include/hw/i386/x86.h

>> @@ -38,6 +38,9 @@ struct X86MachineClass {

>>      bool save_tsc_khz;

>>      /* Enables contiguous-apic-ID mode */

>>      bool compat_apic_id_mode;

>> +

>> +    /* Hyper-V features enabled with 'hyperv=on' */

>> +    uint64_t hyperv_features;

>>  };

>>  

>>  struct X86MachineState {

>> @@ -70,10 +73,14 @@ struct X86MachineState {

>>       * will be translated to MSI messages in the address space.

>>       */

>>      AddressSpace *ioapic_as;

>> +

>> +    /* Hyper-V emulation */

>> +    bool hyperv_enabled;

>>  };

>>  

>>  #define X86_MACHINE_SMM              "smm"

>>  #define X86_MACHINE_ACPI             "acpi"

>> +#define X86_MACHINE_HYPERV           "hyperv"

>>  

>>  #define TYPE_X86_MACHINE   MACHINE_TYPE_NAME("x86")

>>  OBJECT_DECLARE_TYPE(X86MachineState, X86MachineClass, X86_MACHINE)

>> diff --git a/target/i386/cpu.c b/target/i386/cpu.c

>> index 55706c8050fe..d0961c1838ad 100644

>> --- a/target/i386/cpu.c

>> +++ b/target/i386/cpu.c

>> @@ -53,6 +53,7 @@

>>  #include "sysemu/tcg.h"

>>  #include "hw/qdev-properties.h"

>>  #include "hw/i386/topology.h"

>> +#include "hw/i386/x86.h"

>>  #ifndef CONFIG_USER_ONLY

>>  #include "exec/address-spaces.h"

>>  #include "hw/i386/apic_internal.h"

>> @@ -6409,8 +6410,21 @@ static void x86_cpu_filter_features(X86CPU *cpu, bool verbose)

>>  

>>  static void x86_cpu_hyperv_realize(X86CPU *cpu)

>>  {

>> +    X86MachineState *x86ms = X86_MACHINE(qdev_get_machine());

>> +    X86MachineClass *x86mc = X86_MACHINE_GET_CLASS(x86ms);

>> +    uint64_t feat;

>>      size_t len;

>>  

>> +    if (x86ms->hyperv_enabled) {

>> +        feat = x86mc->hyperv_features;

>> +        /* Enlightened VMCS is only available on Intel/VMX */

>> +        if (!cpu_has_vmx(&cpu->env)) {

>> +            feat &= ~BIT(HYPERV_FEAT_EVMCS);

>> +        }

>> +

>> +        cpu->hyperv_features |= feat;

>> +    }

>> +

>>      /* Hyper-V vendor id */

>>      if (!cpu->hyperv_vendor) {

>>          object_property_set_str(OBJECT(cpu), "hv-vendor-id", "Microsoft Hv",

>> -- 

>> 2.25.4

>> 


-- 
Vitaly
diff mbox series

Patch

diff --git a/docs/hyperv.txt b/docs/hyperv.txt
index 5df00da54fc4..1a76a07f8417 100644
--- a/docs/hyperv.txt
+++ b/docs/hyperv.txt
@@ -29,6 +29,14 @@  When any set of the Hyper-V enlightenments is enabled, QEMU changes hypervisor
 identification (CPUID 0x40000000..0x4000000A) to Hyper-V. KVM identification
 and features are kept in leaves 0x40000100..0x40000101.
 
+Hyper-V enlightenments can be enabled in bulk by specifying 'hyperv=on' to an
+x86 machine type:
+
+  qemu-system-x86_64 -machine q35,accel=kvm,kernel-irqchip=split,hyperv=on ...
+
+Note, new enlightenments are only added to the latest (in-develompent) machine
+type, older machine types keep the list of the supported features intact to
+safeguard migration.
 
 3. Existing enlightenments
 ===========================
diff --git a/hw/i386/x86.c b/hw/i386/x86.c
index 3137a2008588..eeecd4e3322f 100644
--- a/hw/i386/x86.c
+++ b/hw/i386/x86.c
@@ -1171,6 +1171,20 @@  static void x86_machine_set_acpi(Object *obj, Visitor *v, const char *name,
     visit_type_OnOffAuto(v, name, &x86ms->acpi, errp);
 }
 
+static bool x86_machine_get_hyperv(Object *obj, Error **errp)
+{
+    X86MachineState *x86ms = X86_MACHINE(obj);
+
+    return x86ms->hyperv_enabled;
+}
+
+static void x86_machine_set_hyperv(Object *obj, bool value, Error **errp)
+{
+    X86MachineState *x86ms = X86_MACHINE(obj);
+
+    x86ms->hyperv_enabled = value;
+}
+
 static void x86_machine_initfn(Object *obj)
 {
     X86MachineState *x86ms = X86_MACHINE(obj);
@@ -1193,6 +1207,16 @@  static void x86_machine_class_init(ObjectClass *oc, void *data)
     x86mc->save_tsc_khz = true;
     nc->nmi_monitor_handler = x86_nmi;
 
+    /* Hyper-V features enabled with 'hyperv=on' */
+    x86mc->hyperv_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_EVMCS) | BIT(HYPERV_FEAT_IPI) |
+        BIT(HYPERV_FEAT_STIMER_DIRECT);
+
     object_class_property_add(oc, X86_MACHINE_SMM, "OnOffAuto",
         x86_machine_get_smm, x86_machine_set_smm,
         NULL, NULL);
@@ -1204,6 +1228,12 @@  static void x86_machine_class_init(ObjectClass *oc, void *data)
         NULL, NULL);
     object_class_property_set_description(oc, X86_MACHINE_ACPI,
         "Enable ACPI");
+
+    object_class_property_add_bool(oc, X86_MACHINE_HYPERV,
+        x86_machine_get_hyperv, x86_machine_set_hyperv);
+
+    object_class_property_set_description(oc, X86_MACHINE_HYPERV,
+        "Enable Hyper-V enlightenments");
 }
 
 static const TypeInfo x86_machine_info = {
diff --git a/include/hw/i386/x86.h b/include/hw/i386/x86.h
index d5dcf7a07fdc..2b989e5fc49d 100644
--- a/include/hw/i386/x86.h
+++ b/include/hw/i386/x86.h
@@ -38,6 +38,9 @@  struct X86MachineClass {
     bool save_tsc_khz;
     /* Enables contiguous-apic-ID mode */
     bool compat_apic_id_mode;
+
+    /* Hyper-V features enabled with 'hyperv=on' */
+    uint64_t hyperv_features;
 };
 
 struct X86MachineState {
@@ -70,10 +73,14 @@  struct X86MachineState {
      * will be translated to MSI messages in the address space.
      */
     AddressSpace *ioapic_as;
+
+    /* Hyper-V emulation */
+    bool hyperv_enabled;
 };
 
 #define X86_MACHINE_SMM              "smm"
 #define X86_MACHINE_ACPI             "acpi"
+#define X86_MACHINE_HYPERV           "hyperv"
 
 #define TYPE_X86_MACHINE   MACHINE_TYPE_NAME("x86")
 OBJECT_DECLARE_TYPE(X86MachineState, X86MachineClass, X86_MACHINE)
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 55706c8050fe..d0961c1838ad 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -53,6 +53,7 @@ 
 #include "sysemu/tcg.h"
 #include "hw/qdev-properties.h"
 #include "hw/i386/topology.h"
+#include "hw/i386/x86.h"
 #ifndef CONFIG_USER_ONLY
 #include "exec/address-spaces.h"
 #include "hw/i386/apic_internal.h"
@@ -6409,8 +6410,21 @@  static void x86_cpu_filter_features(X86CPU *cpu, bool verbose)
 
 static void x86_cpu_hyperv_realize(X86CPU *cpu)
 {
+    X86MachineState *x86ms = X86_MACHINE(qdev_get_machine());
+    X86MachineClass *x86mc = X86_MACHINE_GET_CLASS(x86ms);
+    uint64_t feat;
     size_t len;
 
+    if (x86ms->hyperv_enabled) {
+        feat = x86mc->hyperv_features;
+        /* Enlightened VMCS is only available on Intel/VMX */
+        if (!cpu_has_vmx(&cpu->env)) {
+            feat &= ~BIT(HYPERV_FEAT_EVMCS);
+        }
+
+        cpu->hyperv_features |= feat;
+    }
+
     /* Hyper-V vendor id */
     if (!cpu->hyperv_vendor) {
         object_property_set_str(OBJECT(cpu), "hv-vendor-id", "Microsoft Hv",