diff mbox series

[RFC,09/22] i386: add reserved FEAT_HYPERV_ECX CPUID leaf

Message ID 20200904145431.196885-10-vkuznets@redhat.com
State New
Headers show
Series i386: KVM: expand Hyper-V features early | expand

Commit Message

Vitaly Kuznetsov Sept. 4, 2020, 2:54 p.m. UTC
As a preparation to expanding Hyper-V CPU features early, add
reserved FEAT_HYPERV_ECX CPUID leaf.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 target/i386/cpu.c | 5 +++++
 target/i386/cpu.h | 1 +
 target/i386/kvm.c | 2 ++
 3 files changed, 8 insertions(+)

Comments

Eduardo Habkost Sept. 18, 2020, 10:25 p.m. UTC | #1
On Fri, Sep 04, 2020 at 04:54:18PM +0200, Vitaly Kuznetsov wrote:
> As a preparation to expanding Hyper-V CPU features early, add
> reserved FEAT_HYPERV_ECX CPUID leaf.
> 
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
>  target/i386/cpu.c | 5 +++++
>  target/i386/cpu.h | 1 +
>  target/i386/kvm.c | 2 ++
>  3 files changed, 8 insertions(+)
> 
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index ef3c672cf415..70588571ccb1 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -974,6 +974,11 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
>          },
>          .cpuid = { .eax = 0x40000003, .reg = R_EBX, },
>      },
> +    [FEAT_HYPERV_ECX] = {
> +        .type = CPUID_FEATURE_WORD,
> +        /* reserved */

What does "reserved" mean here?

> +        .cpuid = { .eax = 0x40000003, .reg = R_ECX, },
> +    },
>      [FEAT_HYPERV_EDX] = {
>          .type = CPUID_FEATURE_WORD,
>          .feat_names = {
> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> index 095d0bf75493..39e0e89aa41f 100644
> --- a/target/i386/cpu.h
> +++ b/target/i386/cpu.h
> @@ -521,6 +521,7 @@ typedef enum FeatureWord {
>      FEAT_KVM_HINTS,     /* CPUID[4000_0001].EDX */
>      FEAT_HYPERV_EAX,    /* CPUID[4000_0003].EAX */
>      FEAT_HYPERV_EBX,    /* CPUID[4000_0003].EBX */
> +    FEAT_HYPERV_ECX,    /* CPUID[4000_0003].ECX */
>      FEAT_HYPERV_EDX,    /* CPUID[4000_0003].EDX */
>      FEAT_HV_RECOMM_EAX, /* CPUID[4000_0004].EAX */
>      FEAT_HV_NESTED_EAX, /* CPUID[4000_000A].EAX */
> diff --git a/target/i386/kvm.c b/target/i386/kvm.c
> index 96ac719adca1..259be2d514dd 100644
> --- a/target/i386/kvm.c
> +++ b/target/i386/kvm.c
> @@ -1251,6 +1251,7 @@ static int hyperv_handle_properties(CPUState *cs,
>          if (c) {
>              env->features[FEAT_HYPERV_EAX] = c->eax;
>              env->features[FEAT_HYPERV_EBX] = c->ebx;
> +            env->features[FEAT_HYPERV_ECX] = c->ecx;
>              env->features[FEAT_HYPERV_EDX] = c->edx;
>          }
>  
> @@ -1350,6 +1351,7 @@ static int hyperv_handle_properties(CPUState *cs,
>      c->function = HV_CPUID_FEATURES;
>      c->eax = env->features[FEAT_HYPERV_EAX];
>      c->ebx = env->features[FEAT_HYPERV_EBX];
> +    c->ecx = env->features[FEAT_HYPERV_ECX];
>      c->edx = env->features[FEAT_HYPERV_EDX];
>  
>      c = &cpuid_ent[cpuid_i++];
> -- 
> 2.25.4
>
Vitaly Kuznetsov Sept. 22, 2020, 10:27 a.m. UTC | #2
Eduardo Habkost <ehabkost@redhat.com> writes:

> On Fri, Sep 04, 2020 at 04:54:18PM +0200, Vitaly Kuznetsov wrote:
>> As a preparation to expanding Hyper-V CPU features early, add
>> reserved FEAT_HYPERV_ECX CPUID leaf.
>> 
>> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
>> ---
>>  target/i386/cpu.c | 5 +++++
>>  target/i386/cpu.h | 1 +
>>  target/i386/kvm.c | 2 ++
>>  3 files changed, 8 insertions(+)
>> 
>> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
>> index ef3c672cf415..70588571ccb1 100644
>> --- a/target/i386/cpu.c
>> +++ b/target/i386/cpu.c
>> @@ -974,6 +974,11 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
>>          },
>>          .cpuid = { .eax = 0x40000003, .reg = R_EBX, },
>>      },
>> +    [FEAT_HYPERV_ECX] = {
>> +        .type = CPUID_FEATURE_WORD,
>> +        /* reserved */
>
> What does "reserved" mean here?

This is actually from TLFS, these bits are currently reserved and there
are no features represented by them. We can, of course, short-circuit
this to '0' but I'd prefer to keep it for consistency. I can change to
something like 'Reserved as of TLFS v6.0b' to make it clear. 

>
>> +        .cpuid = { .eax = 0x40000003, .reg = R_ECX, },
>> +    },
>>      [FEAT_HYPERV_EDX] = {
>>          .type = CPUID_FEATURE_WORD,
>>          .feat_names = {
>> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
>> index 095d0bf75493..39e0e89aa41f 100644
>> --- a/target/i386/cpu.h
>> +++ b/target/i386/cpu.h
>> @@ -521,6 +521,7 @@ typedef enum FeatureWord {
>>      FEAT_KVM_HINTS,     /* CPUID[4000_0001].EDX */
>>      FEAT_HYPERV_EAX,    /* CPUID[4000_0003].EAX */
>>      FEAT_HYPERV_EBX,    /* CPUID[4000_0003].EBX */
>> +    FEAT_HYPERV_ECX,    /* CPUID[4000_0003].ECX */
>>      FEAT_HYPERV_EDX,    /* CPUID[4000_0003].EDX */
>>      FEAT_HV_RECOMM_EAX, /* CPUID[4000_0004].EAX */
>>      FEAT_HV_NESTED_EAX, /* CPUID[4000_000A].EAX */
>> diff --git a/target/i386/kvm.c b/target/i386/kvm.c
>> index 96ac719adca1..259be2d514dd 100644
>> --- a/target/i386/kvm.c
>> +++ b/target/i386/kvm.c
>> @@ -1251,6 +1251,7 @@ static int hyperv_handle_properties(CPUState *cs,
>>          if (c) {
>>              env->features[FEAT_HYPERV_EAX] = c->eax;
>>              env->features[FEAT_HYPERV_EBX] = c->ebx;
>> +            env->features[FEAT_HYPERV_ECX] = c->ecx;
>>              env->features[FEAT_HYPERV_EDX] = c->edx;
>>          }
>>  
>> @@ -1350,6 +1351,7 @@ static int hyperv_handle_properties(CPUState *cs,
>>      c->function = HV_CPUID_FEATURES;
>>      c->eax = env->features[FEAT_HYPERV_EAX];
>>      c->ebx = env->features[FEAT_HYPERV_EBX];
>> +    c->ecx = env->features[FEAT_HYPERV_ECX];
>>      c->edx = env->features[FEAT_HYPERV_EDX];
>>  
>>      c = &cpuid_ent[cpuid_i++];
>> -- 
>> 2.25.4
>>
diff mbox series

Patch

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index ef3c672cf415..70588571ccb1 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -974,6 +974,11 @@  static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
         },
         .cpuid = { .eax = 0x40000003, .reg = R_EBX, },
     },
+    [FEAT_HYPERV_ECX] = {
+        .type = CPUID_FEATURE_WORD,
+        /* reserved */
+        .cpuid = { .eax = 0x40000003, .reg = R_ECX, },
+    },
     [FEAT_HYPERV_EDX] = {
         .type = CPUID_FEATURE_WORD,
         .feat_names = {
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 095d0bf75493..39e0e89aa41f 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -521,6 +521,7 @@  typedef enum FeatureWord {
     FEAT_KVM_HINTS,     /* CPUID[4000_0001].EDX */
     FEAT_HYPERV_EAX,    /* CPUID[4000_0003].EAX */
     FEAT_HYPERV_EBX,    /* CPUID[4000_0003].EBX */
+    FEAT_HYPERV_ECX,    /* CPUID[4000_0003].ECX */
     FEAT_HYPERV_EDX,    /* CPUID[4000_0003].EDX */
     FEAT_HV_RECOMM_EAX, /* CPUID[4000_0004].EAX */
     FEAT_HV_NESTED_EAX, /* CPUID[4000_000A].EAX */
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index 96ac719adca1..259be2d514dd 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -1251,6 +1251,7 @@  static int hyperv_handle_properties(CPUState *cs,
         if (c) {
             env->features[FEAT_HYPERV_EAX] = c->eax;
             env->features[FEAT_HYPERV_EBX] = c->ebx;
+            env->features[FEAT_HYPERV_ECX] = c->ecx;
             env->features[FEAT_HYPERV_EDX] = c->edx;
         }
 
@@ -1350,6 +1351,7 @@  static int hyperv_handle_properties(CPUState *cs,
     c->function = HV_CPUID_FEATURES;
     c->eax = env->features[FEAT_HYPERV_EAX];
     c->ebx = env->features[FEAT_HYPERV_EBX];
+    c->ecx = env->features[FEAT_HYPERV_ECX];
     c->edx = env->features[FEAT_HYPERV_EDX];
 
     c = &cpuid_ent[cpuid_i++];