* Re: [Qemu-devel] [PATCH v2] target-i386: add KVM_HINTS_DEDICATED performance hint
[not found] ` <20180209143117.GL13981@localhost.localdomain>
@ 2018-02-09 14:52 ` Wanpeng Li
0 siblings, 0 replies; 4+ messages in thread
From: Wanpeng Li @ 2018-02-09 14:52 UTC (permalink / raw)
To: Eduardo Habkost
Cc: kvm, Paolo Bonzini, Radim Krčmář,
qemu-devel@nongnu.org Developers
2018-02-09 22:31 GMT+08:00 Eduardo Habkost <ehabkost@redhat.com>:
> On Fri, Feb 09, 2018 at 06:15:25AM -0800, Wanpeng Li wrote:
>> From: Wanpeng Li <wanpengli@tencent.com>
>>
>> Add KVM_HINTS_DEDICATED performance hint, guest checks this feature bit
>> to determine if they run on dedicated vCPUs, allowing optimizations such
>> as usage of qspinlocks.
>>
>> Cc: Paolo Bonzini <pbonzini@redhat.com>
>> Cc: Radim Krčmář <rkrcmar@redhat.com>
>> Cc: Eduardo Habkost <ehabkost@redhat.com>
>> Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
> [...]
>> + [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,
>> + },
>
> Do you have a pointer to the KVM patch that adds this bit to
> Documentation/virtual/kvm/cpuid.txt? I would like to wait until
> the KVM CPUID docs are updated before applying the patch to QEMU.
Yeah, please refer to https://lkml.org/lkml/2018/2/9/476
Regards,
Wanpeng Li
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] [PATCH v2] target-i386: add KVM_HINTS_DEDICATED performance hint
[not found] <1518185725-69559-1-git-send-email-wanpengli@tencent.com>
[not found] ` <20180209143117.GL13981@localhost.localdomain>
@ 2018-02-28 12:31 ` Wanpeng Li
2018-02-28 15:05 ` Paolo Bonzini
[not found] ` <20180309141653.GA2871@localhost.localdomain>
2 siblings, 1 reply; 4+ messages in thread
From: Wanpeng Li @ 2018-02-28 12:31 UTC (permalink / raw)
To: kvm, qemu-devel@nongnu.org Developers
Cc: Paolo Bonzini, Radim Krčmář, Eduardo Habkost
Ping,
2018-02-09 22:15 GMT+08:00 Wanpeng Li <kernellwp@gmail.com>:
> From: Wanpeng Li <wanpengli@tencent.com>
>
> Add KVM_HINTS_DEDICATED performance hint, guest checks this feature bit
> to determine if they run on dedicated vCPUs, allowing optimizations such
> as usage of qspinlocks.
>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Radim Krčmář <rkrcmar@redhat.com>
> Cc: Eduardo Habkost <ehabkost@redhat.com>
> Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
> ---
> v1 -> v2:
> * add a new feature word
>
> target/i386/cpu.c | 14 ++++++++++++++
> target/i386/cpu.h | 3 +++
> target/i386/kvm.c | 4 ++++
> 3 files changed, 21 insertions(+)
>
> 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..44ee524 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 */
> @@ -801,6 +804,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
> c = &cpuid_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, &limit, &unused, &unused, &unused);
> --
> 2.7.4
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] [PATCH v2] target-i386: add KVM_HINTS_DEDICATED performance hint
2018-02-28 12:31 ` Wanpeng Li
@ 2018-02-28 15:05 ` Paolo Bonzini
0 siblings, 0 replies; 4+ messages in thread
From: Paolo Bonzini @ 2018-02-28 15:05 UTC (permalink / raw)
To: Wanpeng Li, kvm, qemu-devel@nongnu.org Developers
Cc: Radim Krčmář, Eduardo Habkost
On 28/02/2018 13:31, Wanpeng Li wrote:
> Ping,
> 2018-02-09 22:15 GMT+08:00 Wanpeng Li <kernellwp@gmail.com>:
>> From: Wanpeng Li <wanpengli@tencent.com>
>>
>> Add KVM_HINTS_DEDICATED performance hint, guest checks this feature bit
>> to determine if they run on dedicated vCPUs, allowing optimizations such
>> as usage of qspinlocks.
Eduardo is still on vacation; the patch is okay but the KVM parts are
still in kvm/queue, so I'm just waiting for him (Radim owns the KVM tree
right now). Feel free to post any patch on top of it. You can add
Based-on: <1518185725-69559-1-git-send-email-wanpengli@tencent.com>
when you post anything needing KVM_HINTS_DEDICATED, that way patchew can
apply your series and test it correctly.
Thanks,
Paolo
>> Cc: Paolo Bonzini <pbonzini@redhat.com>
>> Cc: Radim Krčmář <rkrcmar@redhat.com>
>> Cc: Eduardo Habkost <ehabkost@redhat.com>
>> Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
>> ---
>> v1 -> v2:
>> * add a new feature word
>>
>> target/i386/cpu.c | 14 ++++++++++++++
>> target/i386/cpu.h | 3 +++
>> target/i386/kvm.c | 4 ++++
>> 3 files changed, 21 insertions(+)
>>
>> 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..44ee524 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 */
>> @@ -801,6 +804,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
>> c = &cpuid_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, &limit, &unused, &unused, &unused);
>> --
>> 2.7.4
>>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] [PATCH v2] target-i386: add KVM_HINTS_DEDICATED performance hint
[not found] ` <20180309141653.GA2871@localhost.localdomain>
@ 2018-03-10 1:43 ` Wanpeng Li
0 siblings, 0 replies; 4+ messages in thread
From: Wanpeng Li @ 2018-03-10 1:43 UTC (permalink / raw)
To: Eduardo Habkost
Cc: kvm, Paolo Bonzini, Radim Krčmář, Peter Zijlstra,
qemu-devel@nongnu.org
2018-03-09 22:16 GMT+08:00 Eduardo Habkost <ehabkost@redhat.com>:
> On Fri, Feb 09, 2018 at 06:15:25AM -0800, Wanpeng Li wrote:
>> From: Wanpeng Li <wanpengli@tencent.com>
>>
>> Add KVM_HINTS_DEDICATED performance hint, guest checks this feature bit
>> to determine if they run on dedicated vCPUs, allowing optimizations such
>> as usage of qspinlocks.
>>
>> Cc: Paolo Bonzini <pbonzini@redhat.com>
>> Cc: Radim Krčmář <rkrcmar@redhat.com>
>> Cc: Eduardo Habkost <ehabkost@redhat.com>
>> Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
>> ---
>> v1 -> v2:
>> * add a new feature word
>>
>> target/i386/cpu.c | 14 ++++++++++++++
>> target/i386/cpu.h | 3 +++
>> target/i386/kvm.c | 4 ++++
>> 3 files changed, 21 insertions(+)
>>
>> 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,
>
> I suggest naming it "kvm-hint-dedicated", to indicate it's
> KVM-specific.
>
> If there are no objections, I can rename it while applying.
Looks good to me, thanks Eduardo.
Regards,
Wanpeng Li
>
> With the rename:
>
> Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
>
>
>> + 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..44ee524 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 */
>> @@ -801,6 +804,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
>> c = &cpuid_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, &limit, &unused, &unused, &unused);
>> --
>> 2.7.4
>>
>
> --
> Eduardo
^ permalink raw reply [flat|nested] 4+ messages in thread
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[not found] ` <20180209143117.GL13981@localhost.localdomain>
2018-02-09 14:52 ` [Qemu-devel] [PATCH v2] target-i386: add KVM_HINTS_DEDICATED performance hint Wanpeng Li
2018-02-28 12:31 ` Wanpeng Li
2018-02-28 15:05 ` Paolo Bonzini
[not found] ` <20180309141653.GA2871@localhost.localdomain>
2018-03-10 1:43 ` Wanpeng Li
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