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

> 


-- 
Eduardo
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

>> 


-- 
Vitaly
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++];