Re: [Qemu-devel] [PATCH] target-i386: adds PV_DEDICATED hint CPUID feature bit

2018-02-09 Thread Wanpeng Li 
2018-02-09 16:41 GMT+08:00 Paolo Bonzini :
> On 08/02/2018 10:44, Wanpeng Li wrote:
>> From: Wanpeng Li 
>>
>> Add PV_DEDICATED hint cpuid feature bit.
>
> Please add a new feature word, since this is not a PV feature but more
> like a performance hint.

Do it in v2.

Regards,
Wanpeng Li

>
> Thanks,
>
> Paolo
>
>> Cc: Paolo Bonzini 
>> Cc: Radim Krčmář 
>> Cc: Eduardo Habkost 
>> Signed-off-by: Wanpeng Li 
>> ---
>>  target/i386/cpu.c | 4 
>>  target/i386/cpu.h | 3 +++
>>  2 files changed, 7 insertions(+)
>>
>> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
>> index d70954b..cf48931 100644
>> --- a/target/i386/cpu.c
>> +++ b/target/i386/cpu.c
>> @@ -4076,6 +4076,9 @@ static int x86_cpu_filter_features(X86CPU *cpu)
>>  x86_cpu_get_supported_feature_word(w, false);
>>  uint32_t requested_features = env->features[w];
>>  env->features[w] &= host_feat;
>> +if (cpu->pv_dedicated && (w == FEAT_KVM)) {
>> +env->features[w] |= CPUID_PV_DEDICATED;
>> +}
>>  cpu->filtered_features[w] = requested_features & ~env->features[w];
>>  if (cpu->filtered_features[w]) {
>>  rv = 1;
>> @@ -4682,6 +4685,7 @@ static Property x86_cpu_properties[] = {
>>   false),
>>  DEFINE_PROP_BOOL("vmware-cpuid-freq", X86CPU, vmware_cpuid_freq, true),
>>  DEFINE_PROP_BOOL("tcg-cpuid", X86CPU, expose_tcg, true),
>> +DEFINE_PROP_BOOL("pv-dedicated", X86CPU, pv_dedicated, false),
>>
>>  /*
>>   * From "Requirements for Implementing the Microsoft
>> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
>> index f91e37d..8000da5 100644
>> --- a/target/i386/cpu.h
>> +++ b/target/i386/cpu.h
>> @@ -672,6 +672,8 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS];
>>
>>  #define CPUID_8000_0008_EBX_IBPB(1U << 12) /* Indirect Branch 
>> Prediction Barrier */
>>
>> +#define CPUID_PV_DEDICATED (1U << 8)
>> +
>>  #define CPUID_XSAVE_XSAVEOPT   (1U << 0)
>>  #define CPUID_XSAVE_XSAVEC (1U << 1)
>>  #define CPUID_XSAVE_XGETBV1(1U << 2)
>> @@ -1276,6 +1278,7 @@ struct X86CPU {
>>  bool expose_kvm;
>>  bool expose_tcg;
>>  bool migratable;
>> +bool pv_dedicated;
>>  bool max_features; /* Enable all supported features automatically */
>>  uint32_t apic_id;
>>
>>
>

Re: [Qemu-devel] [PATCH] target-i386: adds PV_DEDICATED hint CPUID feature bit

2018-02-09 Thread Wanpeng Li 
2018-02-09 20:46 GMT+08:00 Eduardo Habkost :
> On Fri, Feb 09, 2018 at 08:24:26PM +0800, Wanpeng Li wrote:
>> 2018-02-09 19:46 GMT+08:00 Eduardo Habkost :
>> > On Fri, Feb 09, 2018 at 09:41:41AM +0100, Paolo Bonzini wrote:
>> >> On 08/02/2018 19:12, Eduardo Habkost wrote:
>> >> > On Thu, Feb 08, 2018 at 05:44:20PM +0800, Wanpeng Li wrote:
>> >> >> From: Wanpeng Li 
>> >> >>
>> >> >> Add PV_DEDICATED hint cpuid feature bit.
>> >> >>
>> >> > [...]
>> >> >> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
>> >> >> index d70954b..cf48931 100644
>> >> >> --- a/target/i386/cpu.c
>> >> >> +++ b/target/i386/cpu.c
>> >> >> @@ -4076,6 +4076,9 @@ static int x86_cpu_filter_features(X86CPU *cpu)
>> >> >>  x86_cpu_get_supported_feature_word(w, false);
>> >> >>  uint32_t requested_features = env->features[w];
>> >> >>  env->features[w] &= host_feat;
>> >> >> +if (cpu->pv_dedicated && (w == FEAT_KVM)) {
>> >> >> +env->features[w] |= CPUID_PV_DEDICATED;
>> >> >> +}
>> >> >
>> >> > Why do this trick here instead of just adding "pv-dedicated" to
>> >> > feature_word_info[FEAT_KVM].feat_names?
>> >>
>> >> I think because it can be added independent of KVM_GET_SUPPORTED_CPUID.
>> >
>> > If QEMU knows it can be enabled if outside GET_SUPPORTED_CPUID,
>> > kvm_arch_get_supported_cpuid() can return it as supported.
>>
>> The guest fails to detect the new cpuid this time.
>
> This should fix it:
>
> diff --git a/target/i386/kvm.c b/target/i386/kvm.c
> index a0aad808bd..44ee524188 100644
> --- a/target/i386/kvm.c
> +++ b/target/i386/kvm.c
> @@ -804,6 +804,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
>  c = _data.entries[cpuid_i++];
>  c->function = KVM_CPUID_FEATURES | kvm_base;
>  c->eax = env->features[FEAT_KVM];
> +c->edx = env->features[FEAT_KVM_HINTS];
>  }
>
>  cpu_x86_cpuid(env, 0, 0, , , , );
>

Yeah, thanks, fold this in v2.

Regards,
Wanpeng Li

>>
>> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
>> index d70954b..e2974ad 100644
>> --- a/target/i386/cpu.c
>> +++ b/target/i386/cpu.c
>> @@ -358,6 +358,20 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] 
>> = {
>>  .cpuid_eax = KVM_CPUID_FEATURES, .cpuid_reg = R_EAX,
>>  .tcg_features = TCG_KVM_FEATURES,
>>  },
>> +[FEAT_KVM_HINTS] = {
>> +.feat_names = {
>> +"hint-dedicated", NULL, NULL, NULL,
>> +NULL, NULL, NULL, NULL,
>> +NULL, NULL, NULL, NULL,
>> +NULL, NULL, NULL, NULL,
>> +NULL, NULL, NULL, NULL,
>> +NULL, NULL, NULL, NULL,
>> +NULL, NULL, NULL, NULL,
>> +NULL, NULL, NULL, NULL,
>> +},
>> +.cpuid_eax = KVM_CPUID_FEATURES, .cpuid_reg = R_EDX,
>> +.tcg_features = TCG_KVM_FEATURES,
>> +},
>>  [FEAT_HYPERV_EAX] = {
>>  .feat_names = {
>>  NULL /* hv_msr_vp_runtime_access */, NULL /*
>> hv_msr_time_refcount_access */,
>> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
>> index f91e37d..9f73692 100644
>> --- a/target/i386/cpu.h
>> +++ b/target/i386/cpu.h
>> @@ -475,6 +475,7 @@ typedef enum FeatureWord {
>>  FEAT_8000_0008_EBX, /* CPUID[8000_0008].EBX */
>>  FEAT_C000_0001_EDX, /* CPUID[C000_0001].EDX */
>>  FEAT_KVM,   /* CPUID[4000_0001].EAX (KVM_CPUID_FEATURES) */
>> +FEAT_KVM_HINTS, /* CPUID[4000_0001].EDX */
>>  FEAT_HYPERV_EAX,/* CPUID[4000_0003].EAX */
>>  FEAT_HYPERV_EBX,/* CPUID[4000_0003].EBX */
>>  FEAT_HYPERV_EDX,/* CPUID[4000_0003].EDX */
>> @@ -670,6 +671,8 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS];
>>  #define CPUID_7_0_EDX_AVX512_4FMAPS (1U << 3) /* AVX512 Multiply
>> Accumulation Single Precision */
>>  #define CPUID_7_0_EDX_SPEC_CTRL (1U << 26) /* Speculation Control */
>>
>> +#define KVM_HINTS_DEDICATED (1U << 0)
>> +
>>  #define CPUID_8000_0008_EBX_IBPB(1U << 12) /* Indirect Branch
>> Prediction Barrier */
>>
>>  #define CPUID_XSAVE_XSAVEOPT   (1U << 0)
>> diff --git a/target/i386/kvm.c b/target/i386/kvm.c
>> index ad4b159..a0aad80 100644
>> --- a/target/i386/kvm.c
>> +++ b/target/i386/kvm.c
>> @@ -383,6 +383,9 @@ uint32_t kvm_arch_get_supported_cpuid(KVMState *s,
>> uint32_t function,
>>  if (!kvm_irqchip_in_kernel()) {
>>  ret &= ~(1U << KVM_FEATURE_PV_UNHALT);
>>  }
>> +} else if (function == KVM_CPUID_FEATURES && reg == R_EDX) {
>> +ret |= KVM_HINTS_DEDICATED;
>> +found = 1;
>>  }
>>
>>  /* fallback for older kernels */
>>
>>
>> Regards,
>> Wanpeng Li
>
> --
> Eduardo

Re: [Qemu-devel] [PATCH] target-i386: adds PV_DEDICATED hint CPUID feature bit

2018-02-09 Thread Eduardo Habkost 
On Fri, Feb 09, 2018 at 08:24:26PM +0800, Wanpeng Li wrote:
> 2018-02-09 19:46 GMT+08:00 Eduardo Habkost :
> > On Fri, Feb 09, 2018 at 09:41:41AM +0100, Paolo Bonzini wrote:
> >> On 08/02/2018 19:12, Eduardo Habkost wrote:
> >> > On Thu, Feb 08, 2018 at 05:44:20PM +0800, Wanpeng Li wrote:
> >> >> From: Wanpeng Li 
> >> >>
> >> >> Add PV_DEDICATED hint cpuid feature bit.
> >> >>
> >> > [...]
> >> >> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> >> >> index d70954b..cf48931 100644
> >> >> --- a/target/i386/cpu.c
> >> >> +++ b/target/i386/cpu.c
> >> >> @@ -4076,6 +4076,9 @@ static int x86_cpu_filter_features(X86CPU *cpu)
> >> >>  x86_cpu_get_supported_feature_word(w, false);
> >> >>  uint32_t requested_features = env->features[w];
> >> >>  env->features[w] &= host_feat;
> >> >> +if (cpu->pv_dedicated && (w == FEAT_KVM)) {
> >> >> +env->features[w] |= CPUID_PV_DEDICATED;
> >> >> +}
> >> >
> >> > Why do this trick here instead of just adding "pv-dedicated" to
> >> > feature_word_info[FEAT_KVM].feat_names?
> >>
> >> I think because it can be added independent of KVM_GET_SUPPORTED_CPUID.
> >
> > If QEMU knows it can be enabled if outside GET_SUPPORTED_CPUID,
> > kvm_arch_get_supported_cpuid() can return it as supported.
> 
> The guest fails to detect the new cpuid this time.

This should fix it:

diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index a0aad808bd..44ee524188 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -804,6 +804,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
 c = _data.entries[cpuid_i++];
 c->function = KVM_CPUID_FEATURES | kvm_base;
 c->eax = env->features[FEAT_KVM];
+c->edx = env->features[FEAT_KVM_HINTS];
 }
 
 cpu_x86_cpuid(env, 0, 0, , , , );

> 
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index d70954b..e2974ad 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -358,6 +358,20 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] 
> = {
>  .cpuid_eax = KVM_CPUID_FEATURES, .cpuid_reg = R_EAX,
>  .tcg_features = TCG_KVM_FEATURES,
>  },
> +[FEAT_KVM_HINTS] = {
> +.feat_names = {
> +"hint-dedicated", NULL, NULL, NULL,
> +NULL, NULL, NULL, NULL,
> +NULL, NULL, NULL, NULL,
> +NULL, NULL, NULL, NULL,
> +NULL, NULL, NULL, NULL,
> +NULL, NULL, NULL, NULL,
> +NULL, NULL, NULL, NULL,
> +NULL, NULL, NULL, NULL,
> +},
> +.cpuid_eax = KVM_CPUID_FEATURES, .cpuid_reg = R_EDX,
> +.tcg_features = TCG_KVM_FEATURES,
> +},
>  [FEAT_HYPERV_EAX] = {
>  .feat_names = {
>  NULL /* hv_msr_vp_runtime_access */, NULL /*
> hv_msr_time_refcount_access */,
> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> index f91e37d..9f73692 100644
> --- a/target/i386/cpu.h
> +++ b/target/i386/cpu.h
> @@ -475,6 +475,7 @@ typedef enum FeatureWord {
>  FEAT_8000_0008_EBX, /* CPUID[8000_0008].EBX */
>  FEAT_C000_0001_EDX, /* CPUID[C000_0001].EDX */
>  FEAT_KVM,   /* CPUID[4000_0001].EAX (KVM_CPUID_FEATURES) */
> +FEAT_KVM_HINTS, /* CPUID[4000_0001].EDX */
>  FEAT_HYPERV_EAX,/* CPUID[4000_0003].EAX */
>  FEAT_HYPERV_EBX,/* CPUID[4000_0003].EBX */
>  FEAT_HYPERV_EDX,/* CPUID[4000_0003].EDX */
> @@ -670,6 +671,8 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS];
>  #define CPUID_7_0_EDX_AVX512_4FMAPS (1U << 3) /* AVX512 Multiply
> Accumulation Single Precision */
>  #define CPUID_7_0_EDX_SPEC_CTRL (1U << 26) /* Speculation Control */
> 
> +#define KVM_HINTS_DEDICATED (1U << 0)
> +
>  #define CPUID_8000_0008_EBX_IBPB(1U << 12) /* Indirect Branch
> Prediction Barrier */
> 
>  #define CPUID_XSAVE_XSAVEOPT   (1U << 0)
> diff --git a/target/i386/kvm.c b/target/i386/kvm.c
> index ad4b159..a0aad80 100644
> --- a/target/i386/kvm.c
> +++ b/target/i386/kvm.c
> @@ -383,6 +383,9 @@ uint32_t kvm_arch_get_supported_cpuid(KVMState *s,
> uint32_t function,
>  if (!kvm_irqchip_in_kernel()) {
>  ret &= ~(1U << KVM_FEATURE_PV_UNHALT);
>  }
> +} else if (function == KVM_CPUID_FEATURES && reg == R_EDX) {
> +ret |= KVM_HINTS_DEDICATED;
> +found = 1;
>  }
> 
>  /* fallback for older kernels */
> 
> 
> Regards,
> Wanpeng Li

-- 
Eduardo

Re: [Qemu-devel] [PATCH] target-i386: adds PV_DEDICATED hint CPUID feature bit

2018-02-09 Thread Paolo Bonzini 
On 09/02/2018 13:24, Wanpeng Li wrote:
> The guest fails to detect the new cpuid this time.

You have to debug the KVM_SET_CPUID2 ioctls and see why it is not set.

Paolo

> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index d70954b..e2974ad 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -358,6 +358,20 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] 
> = {
>  .cpuid_eax = KVM_CPUID_FEATURES, .cpuid_reg = R_EAX,
>  .tcg_features = TCG_KVM_FEATURES,
>  },
> +[FEAT_KVM_HINTS] = {
> +.feat_names = {
> +"hint-dedicated", NULL, NULL, NULL,
> +NULL, NULL, NULL, NULL,
> +NULL, NULL, NULL, NULL,
> +NULL, NULL, NULL, NULL,
> +NULL, NULL, NULL, NULL,
> +NULL, NULL, NULL, NULL,
> +NULL, NULL, NULL, NULL,
> +NULL, NULL, NULL, NULL,
> +},
> +.cpuid_eax = KVM_CPUID_FEATURES, .cpuid_reg = R_EDX,
> +.tcg_features = TCG_KVM_FEATURES,
> +},

Re: [Qemu-devel] [PATCH] target-i386: adds PV_DEDICATED hint CPUID feature bit

2018-02-09 Thread Wanpeng Li 
2018-02-09 19:46 GMT+08:00 Eduardo Habkost :
> On Fri, Feb 09, 2018 at 09:41:41AM +0100, Paolo Bonzini wrote:
>> On 08/02/2018 19:12, Eduardo Habkost wrote:
>> > On Thu, Feb 08, 2018 at 05:44:20PM +0800, Wanpeng Li wrote:
>> >> From: Wanpeng Li 
>> >>
>> >> Add PV_DEDICATED hint cpuid feature bit.
>> >>
>> > [...]
>> >> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
>> >> index d70954b..cf48931 100644
>> >> --- a/target/i386/cpu.c
>> >> +++ b/target/i386/cpu.c
>> >> @@ -4076,6 +4076,9 @@ static int x86_cpu_filter_features(X86CPU *cpu)
>> >>  x86_cpu_get_supported_feature_word(w, false);
>> >>  uint32_t requested_features = env->features[w];
>> >>  env->features[w] &= host_feat;
>> >> +if (cpu->pv_dedicated && (w == FEAT_KVM)) {
>> >> +env->features[w] |= CPUID_PV_DEDICATED;
>> >> +}
>> >
>> > Why do this trick here instead of just adding "pv-dedicated" to
>> > feature_word_info[FEAT_KVM].feat_names?
>>
>> I think because it can be added independent of KVM_GET_SUPPORTED_CPUID.
>
> If QEMU knows it can be enabled if outside GET_SUPPORTED_CPUID,
> kvm_arch_get_supported_cpuid() can return it as supported.

The guest fails to detect the new cpuid this time.

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index d70954b..e2974ad 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -358,6 +358,20 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
 .cpuid_eax = KVM_CPUID_FEATURES, .cpuid_reg = R_EAX,
 .tcg_features = TCG_KVM_FEATURES,
 },
+[FEAT_KVM_HINTS] = {
+.feat_names = {
+"hint-dedicated", NULL, NULL, NULL,
+NULL, NULL, NULL, NULL,
+NULL, NULL, NULL, NULL,
+NULL, NULL, NULL, NULL,
+NULL, NULL, NULL, NULL,
+NULL, NULL, NULL, NULL,
+NULL, NULL, NULL, NULL,
+NULL, NULL, NULL, NULL,
+},
+.cpuid_eax = KVM_CPUID_FEATURES, .cpuid_reg = R_EDX,
+.tcg_features = TCG_KVM_FEATURES,
+},
 [FEAT_HYPERV_EAX] = {
 .feat_names = {
 NULL /* hv_msr_vp_runtime_access */, NULL /*
hv_msr_time_refcount_access */,
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index f91e37d..9f73692 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -475,6 +475,7 @@ typedef enum FeatureWord {
 FEAT_8000_0008_EBX, /* CPUID[8000_0008].EBX */
 FEAT_C000_0001_EDX, /* CPUID[C000_0001].EDX */
 FEAT_KVM,   /* CPUID[4000_0001].EAX (KVM_CPUID_FEATURES) */
+FEAT_KVM_HINTS, /* CPUID[4000_0001].EDX */
 FEAT_HYPERV_EAX,/* CPUID[4000_0003].EAX */
 FEAT_HYPERV_EBX,/* CPUID[4000_0003].EBX */
 FEAT_HYPERV_EDX,/* CPUID[4000_0003].EDX */
@@ -670,6 +671,8 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS];
 #define CPUID_7_0_EDX_AVX512_4FMAPS (1U << 3) /* AVX512 Multiply
Accumulation Single Precision */
 #define CPUID_7_0_EDX_SPEC_CTRL (1U << 26) /* Speculation Control */

+#define KVM_HINTS_DEDICATED (1U << 0)
+
 #define CPUID_8000_0008_EBX_IBPB(1U << 12) /* Indirect Branch
Prediction Barrier */

 #define CPUID_XSAVE_XSAVEOPT   (1U << 0)
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index ad4b159..a0aad80 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -383,6 +383,9 @@ uint32_t kvm_arch_get_supported_cpuid(KVMState *s,
uint32_t function,
 if (!kvm_irqchip_in_kernel()) {
 ret &= ~(1U << KVM_FEATURE_PV_UNHALT);
 }
+} else if (function == KVM_CPUID_FEATURES && reg == R_EDX) {
+ret |= KVM_HINTS_DEDICATED;
+found = 1;
 }

 /* fallback for older kernels */


Regards,
Wanpeng Li

Re: [Qemu-devel] [PATCH] target-i386: adds PV_DEDICATED hint CPUID feature bit

2018-02-09 Thread Eduardo Habkost 
On Fri, Feb 09, 2018 at 09:41:41AM +0100, Paolo Bonzini wrote:
> On 08/02/2018 19:12, Eduardo Habkost wrote:
> > On Thu, Feb 08, 2018 at 05:44:20PM +0800, Wanpeng Li wrote:
> >> From: Wanpeng Li 
> >>
> >> Add PV_DEDICATED hint cpuid feature bit.
> >>
> > [...]
> >> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> >> index d70954b..cf48931 100644
> >> --- a/target/i386/cpu.c
> >> +++ b/target/i386/cpu.c
> >> @@ -4076,6 +4076,9 @@ static int x86_cpu_filter_features(X86CPU *cpu)
> >>  x86_cpu_get_supported_feature_word(w, false);
> >>  uint32_t requested_features = env->features[w];
> >>  env->features[w] &= host_feat;
> >> +if (cpu->pv_dedicated && (w == FEAT_KVM)) {
> >> +env->features[w] |= CPUID_PV_DEDICATED;
> >> +}
> > 
> > Why do this trick here instead of just adding "pv-dedicated" to
> > feature_word_info[FEAT_KVM].feat_names?
> 
> I think because it can be added independent of KVM_GET_SUPPORTED_CPUID.

If QEMU knows it can be enabled if outside GET_SUPPORTED_CPUID,
kvm_arch_get_supported_cpuid() can return it as supported.

-- 
Eduardo

Re: [Qemu-devel] [PATCH] target-i386: adds PV_DEDICATED hint CPUID feature bit

2018-02-09 Thread Paolo Bonzini 
On 08/02/2018 19:12, Eduardo Habkost wrote:
> On Thu, Feb 08, 2018 at 05:44:20PM +0800, Wanpeng Li wrote:
>> From: Wanpeng Li 
>>
>> Add PV_DEDICATED hint cpuid feature bit.
>>
> [...]
>> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
>> index d70954b..cf48931 100644
>> --- a/target/i386/cpu.c
>> +++ b/target/i386/cpu.c
>> @@ -4076,6 +4076,9 @@ static int x86_cpu_filter_features(X86CPU *cpu)
>>  x86_cpu_get_supported_feature_word(w, false);
>>  uint32_t requested_features = env->features[w];
>>  env->features[w] &= host_feat;
>> +if (cpu->pv_dedicated && (w == FEAT_KVM)) {
>> +env->features[w] |= CPUID_PV_DEDICATED;
>> +}
> 
> Why do this trick here instead of just adding "pv-dedicated" to
> feature_word_info[FEAT_KVM].feat_names?

I think because it can be added independent of KVM_GET_SUPPORTED_CPUID.

Paolo

Re: [Qemu-devel] [PATCH] target-i386: adds PV_DEDICATED hint CPUID feature bit

2018-02-09 Thread Paolo Bonzini 
On 08/02/2018 10:44, Wanpeng Li wrote:
> From: Wanpeng Li 
> 
> Add PV_DEDICATED hint cpuid feature bit.

Please add a new feature word, since this is not a PV feature but more
like a performance hint.

Thanks,

Paolo

> Cc: Paolo Bonzini 
> Cc: Radim Krčmář 
> Cc: Eduardo Habkost 
> Signed-off-by: Wanpeng Li 
> ---
>  target/i386/cpu.c | 4 
>  target/i386/cpu.h | 3 +++
>  2 files changed, 7 insertions(+)
> 
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index d70954b..cf48931 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -4076,6 +4076,9 @@ static int x86_cpu_filter_features(X86CPU *cpu)
>  x86_cpu_get_supported_feature_word(w, false);
>  uint32_t requested_features = env->features[w];
>  env->features[w] &= host_feat;
> +if (cpu->pv_dedicated && (w == FEAT_KVM)) {
> +env->features[w] |= CPUID_PV_DEDICATED;
> +}
>  cpu->filtered_features[w] = requested_features & ~env->features[w];
>  if (cpu->filtered_features[w]) {
>  rv = 1;
> @@ -4682,6 +4685,7 @@ static Property x86_cpu_properties[] = {
>   false),
>  DEFINE_PROP_BOOL("vmware-cpuid-freq", X86CPU, vmware_cpuid_freq, true),
>  DEFINE_PROP_BOOL("tcg-cpuid", X86CPU, expose_tcg, true),
> +DEFINE_PROP_BOOL("pv-dedicated", X86CPU, pv_dedicated, false),
>  
>  /*
>   * From "Requirements for Implementing the Microsoft
> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> index f91e37d..8000da5 100644
> --- a/target/i386/cpu.h
> +++ b/target/i386/cpu.h
> @@ -672,6 +672,8 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS];
>  
>  #define CPUID_8000_0008_EBX_IBPB(1U << 12) /* Indirect Branch Prediction 
> Barrier */
>  
> +#define CPUID_PV_DEDICATED (1U << 8)
> +
>  #define CPUID_XSAVE_XSAVEOPT   (1U << 0)
>  #define CPUID_XSAVE_XSAVEC (1U << 1)
>  #define CPUID_XSAVE_XGETBV1(1U << 2)
> @@ -1276,6 +1278,7 @@ struct X86CPU {
>  bool expose_kvm;
>  bool expose_tcg;
>  bool migratable;
> +bool pv_dedicated;
>  bool max_features; /* Enable all supported features automatically */
>  uint32_t apic_id;
>  
>

Re: [Qemu-devel] [PATCH] target-i386: adds PV_DEDICATED hint CPUID feature bit

2018-02-08 Thread Wanpeng Li 
2018-02-09 2:12 GMT+08:00 Eduardo Habkost :
> On Thu, Feb 08, 2018 at 05:44:20PM +0800, Wanpeng Li wrote:
>> From: Wanpeng Li 
>>
>> Add PV_DEDICATED hint cpuid feature bit.
>>
> [...]
>> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
>> index d70954b..cf48931 100644
>> --- a/target/i386/cpu.c
>> +++ b/target/i386/cpu.c
>> @@ -4076,6 +4076,9 @@ static int x86_cpu_filter_features(X86CPU *cpu)
>>  x86_cpu_get_supported_feature_word(w, false);
>>  uint32_t requested_features = env->features[w];
>>  env->features[w] &= host_feat;
>> +if (cpu->pv_dedicated && (w == FEAT_KVM)) {
>> +env->features[w] |= CPUID_PV_DEDICATED;
>> +}
>
> Why do this trick here instead of just adding "pv-dedicated" to
> feature_word_info[FEAT_KVM].feat_names?

Actually this hint doesn't depend on KVM, just qemu command-line gives
a hint and then guest kernel can recognize it. Is there a nicer
proposal in qemu? Paolo?

Regards,
Wanpeng Li

Re: [Qemu-devel] [PATCH] target-i386: adds PV_DEDICATED hint CPUID feature bit

2018-02-08 Thread Eduardo Habkost 
On Thu, Feb 08, 2018 at 05:44:20PM +0800, Wanpeng Li wrote:
> From: Wanpeng Li 
> 
> Add PV_DEDICATED hint cpuid feature bit.
> 
[...]
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index d70954b..cf48931 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -4076,6 +4076,9 @@ static int x86_cpu_filter_features(X86CPU *cpu)
>  x86_cpu_get_supported_feature_word(w, false);
>  uint32_t requested_features = env->features[w];
>  env->features[w] &= host_feat;
> +if (cpu->pv_dedicated && (w == FEAT_KVM)) {
> +env->features[w] |= CPUID_PV_DEDICATED;
> +}

Why do this trick here instead of just adding "pv-dedicated" to
feature_word_info[FEAT_KVM].feat_names?

> [...]

-- 
Eduardo

[Qemu-devel] [PATCH] target-i386: adds PV_DEDICATED hint CPUID feature bit

2018-02-08 Thread Wanpeng Li 
From: Wanpeng Li 

Add PV_DEDICATED hint cpuid feature bit.

Cc: Paolo Bonzini 
Cc: Radim Krčmář 
Cc: Eduardo Habkost 
Signed-off-by: Wanpeng Li 
---
 target/i386/cpu.c | 4 
 target/i386/cpu.h | 3 +++
 2 files changed, 7 insertions(+)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index d70954b..cf48931 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -4076,6 +4076,9 @@ static int x86_cpu_filter_features(X86CPU *cpu)
 x86_cpu_get_supported_feature_word(w, false);
 uint32_t requested_features = env->features[w];
 env->features[w] &= host_feat;
+if (cpu->pv_dedicated && (w == FEAT_KVM)) {
+env->features[w] |= CPUID_PV_DEDICATED;
+}
 cpu->filtered_features[w] = requested_features & ~env->features[w];
 if (cpu->filtered_features[w]) {
 rv = 1;
@@ -4682,6 +4685,7 @@ static Property x86_cpu_properties[] = {
  false),
 DEFINE_PROP_BOOL("vmware-cpuid-freq", X86CPU, vmware_cpuid_freq, true),
 DEFINE_PROP_BOOL("tcg-cpuid", X86CPU, expose_tcg, true),
+DEFINE_PROP_BOOL("pv-dedicated", X86CPU, pv_dedicated, false),
 
 /*
  * From "Requirements for Implementing the Microsoft
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index f91e37d..8000da5 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -672,6 +672,8 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS];
 
 #define CPUID_8000_0008_EBX_IBPB(1U << 12) /* Indirect Branch Prediction 
Barrier */
 
+#define CPUID_PV_DEDICATED (1U << 8)
+
 #define CPUID_XSAVE_XSAVEOPT   (1U << 0)
 #define CPUID_XSAVE_XSAVEC (1U << 1)
 #define CPUID_XSAVE_XGETBV1(1U << 2)
@@ -1276,6 +1278,7 @@ struct X86CPU {
 bool expose_kvm;
 bool expose_tcg;
 bool migratable;
+bool pv_dedicated;
 bool max_features; /* Enable all supported features automatically */
 uint32_t apic_id;
 
-- 
2.7.4