[PATCH] target/i386/kvm: Add Hyper-V direct tlb flush support

[PATCH] target/i386/kvm: Add Hyper-V direct tlb flush support

[lantianyu1986]

From: Tianyu Lan <Tianyu.Lan@microsoft.com>

Hyper-V direct tlb flush targets KVM on Hyper-V guest.
Enable direct TLB flush for its guests meaning that TLB
flush hypercalls are handled by Level 0 hypervisor (Hyper-V)
bypassing KVM in Level 1. Due to the different ABI for hypercall
parameters between Hyper-V and KVM, KVM capabilities should be
hidden when enable Hyper-V direct tlb flush otherwise KVM
hypercalls may be intercepted by Hyper-V. Add new parameter
"hv-direct-tlbflush". Check expose_kvm and Hyper-V tlb flush
capability status before enabling the feature.

Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
 docs/hyperv.txt           | 12 ++++++++++++
 linux-headers/linux/kvm.h |  1 +
 target/i386/cpu.c         |  2 ++
 target/i386/cpu.h         |  1 +
 target/i386/kvm.c         | 21 +++++++++++++++++++++
 5 files changed, 37 insertions(+)

diff --git a/docs/hyperv.txt b/docs/hyperv.txt
index 8fdf25c829..ceab8c21fe 100644
--- a/docs/hyperv.txt
+++ b/docs/hyperv.txt
@@ -184,6 +184,18 @@ enabled.
 
 Requires: hv-vpindex, hv-synic, hv-time, hv-stimer
 
+3.18. hv-direct-tlbflush
+=======================
+The enlightenment targets KVM on Hyper-V guest. Enable direct TLB flush for
+its guests meaning that TLB flush hypercalls are handled by Level 0 hypervisor
+(Hyper-V) bypassing KVM in Level 1. Due to the different ABI for hypercall
+parameters between Hyper-V and KVM, enabling this capability effectively
+disables all hypercall handling by KVM (as some KVM hypercall may be mistakenly
+treated as TLB flush hypercalls by Hyper-V). So kvm capability should not show
+to guest when enable this capability. If not, user will fail to enable this
+capability.
+
+Requires: hv-tlbflush, -kvm
 
 4. Development features
 ========================
diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
index 18892d6541..923fb33a01 100644
--- a/linux-headers/linux/kvm.h
+++ b/linux-headers/linux/kvm.h
@@ -995,6 +995,7 @@ struct kvm_ppc_resize_hpt {
 #define KVM_CAP_ARM_SVE 170
 #define KVM_CAP_ARM_PTRAUTH_ADDRESS 171
 #define KVM_CAP_ARM_PTRAUTH_GENERIC 172
+#define KVM_CAP_HYPERV_DIRECT_TLBFLUSH 174
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 44f1bbdcac..7bc7fee512 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -6156,6 +6156,8 @@ static Property x86_cpu_properties[] = {
                       HYPERV_FEAT_IPI, 0),
     DEFINE_PROP_BIT64("hv-stimer-direct", X86CPU, hyperv_features,
                       HYPERV_FEAT_STIMER_DIRECT, 0),
+    DEFINE_PROP_BIT64("hv-direct-tlbflush", X86CPU, hyperv_features,
+                      HYPERV_FEAT_DIRECT_TLBFLUSH, 0),
     DEFINE_PROP_BOOL("hv-passthrough", X86CPU, hyperv_passthrough, false),
 
     DEFINE_PROP_BOOL("check", X86CPU, check_cpuid, true),
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index eaa5395aa5..3cb105f7d6 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -907,6 +907,7 @@ typedef uint64_t FeatureWordArray[FEATURE_WORDS];
 #define HYPERV_FEAT_EVMCS               12
 #define HYPERV_FEAT_IPI                 13
 #define HYPERV_FEAT_STIMER_DIRECT       14
+#define HYPERV_FEAT_DIRECT_TLBFLUSH     15
 
 #ifndef HYPERV_SPINLOCK_NEVER_RETRY
 #define HYPERV_SPINLOCK_NEVER_RETRY             0xFFFFFFFF
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index 11b9c854b5..8e999dbcf1 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -1235,6 +1235,27 @@ static int hyperv_handle_properties(CPUState *cs,
         r |= 1;
     }
 
+    if (hyperv_feat_enabled(cpu, HYPERV_FEAT_DIRECT_TLBFLUSH)) {
+        if (!kvm_check_extension(cs->kvm_state,
+            KVM_CAP_HYPERV_DIRECT_TLBFLUSH)) {
+            fprintf(stderr,
+                    "Kernel doesn't support Hyper-V direct tlbflush.\n");
+            r = -ENOSYS;
+            goto free;
+        }
+
+        if (cpu->expose_kvm ||
+            !hyperv_feat_enabled(cpu, HYPERV_FEAT_TLBFLUSH)) {
+            fprintf(stderr, "Hyper-V direct tlbflush requires Hyper-V %s"
+                    " and not expose KVM.\n",
+                    kvm_hyperv_properties[HYPERV_FEAT_TLBFLUSH].desc);
+            r = -ENOSYS;
+            goto free;
+        }
+
+        kvm_vcpu_enable_cap(cs, KVM_CAP_HYPERV_DIRECT_TLBFLUSH, 0, 0);
+    }
+
     /* Not exposed by KVM but needed to make CPU hotplug in Windows work */
     env->features[FEAT_HYPERV_EDX] |= HV_CPU_DYNAMIC_PARTITIONING_AVAILABLE;
 
-- 
2.14.5

Re: [PATCH] target/i386/kvm: Add Hyper-V direct tlb flush support

[Vitaly Kuznetsov]

lantianyu1986@gmail.com writes:

> From: Tianyu Lan <Tianyu.Lan@microsoft.com>
>

(Please also Cc: Roman on you Hyper-V related submissions to QEMU who's
known to be a great reviewer)

> Hyper-V direct tlb flush targets KVM on Hyper-V guest.
> Enable direct TLB flush for its guests meaning that TLB
> flush hypercalls are handled by Level 0 hypervisor (Hyper-V)
> bypassing KVM in Level 1. Due to the different ABI for hypercall
> parameters between Hyper-V and KVM, KVM capabilities should be
> hidden when enable Hyper-V direct tlb flush otherwise KVM
> hypercalls may be intercepted by Hyper-V. Add new parameter
> "hv-direct-tlbflush". Check expose_kvm and Hyper-V tlb flush
> capability status before enabling the feature.
>
> Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
> ---
>  docs/hyperv.txt           | 12 ++++++++++++
>  linux-headers/linux/kvm.h |  1 +
>  target/i386/cpu.c         |  2 ++
>  target/i386/cpu.h         |  1 +
>  target/i386/kvm.c         | 21 +++++++++++++++++++++
>  5 files changed, 37 insertions(+)
>
> diff --git a/docs/hyperv.txt b/docs/hyperv.txt
> index 8fdf25c829..ceab8c21fe 100644
> --- a/docs/hyperv.txt
> +++ b/docs/hyperv.txt
> @@ -184,6 +184,18 @@ enabled.
>  
>  Requires: hv-vpindex, hv-synic, hv-time, hv-stimer
>  
> +3.18. hv-direct-tlbflush
> +=======================
> +The enlightenment targets KVM on Hyper-V guest. Enable direct TLB flush for
> +its guests meaning that TLB flush hypercalls are handled by Level 0 hypervisor
> +(Hyper-V) bypassing KVM in Level 1. Due to the different ABI for hypercall
> +parameters between Hyper-V and KVM, enabling this capability effectively
> +disables all hypercall handling by KVM (as some KVM hypercall may be mistakenly
> +treated as TLB flush hypercalls by Hyper-V). So kvm capability should not show
> +to guest when enable this capability. If not, user will fail to enable this
> +capability.
> +
> +Requires: hv-tlbflush, -kvm
>  
>  4. Development features
>  ========================
> diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
> index 18892d6541..923fb33a01 100644
> --- a/linux-headers/linux/kvm.h
> +++ b/linux-headers/linux/kvm.h
> @@ -995,6 +995,7 @@ struct kvm_ppc_resize_hpt {
>  #define KVM_CAP_ARM_SVE 170
>  #define KVM_CAP_ARM_PTRAUTH_ADDRESS 171
>  #define KVM_CAP_ARM_PTRAUTH_GENERIC 172
> +#define KVM_CAP_HYPERV_DIRECT_TLBFLUSH 174

I was once told that scripts/update-linux-headers.sh script is supposed
to be used instead of cherry-picking stuff you need (adn this would be a
separate patch - update linux headers to smth).

>  
>  #ifdef KVM_CAP_IRQ_ROUTING
>  
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index 44f1bbdcac..7bc7fee512 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -6156,6 +6156,8 @@ static Property x86_cpu_properties[] = {
>                        HYPERV_FEAT_IPI, 0),
>      DEFINE_PROP_BIT64("hv-stimer-direct", X86CPU, hyperv_features,
>                        HYPERV_FEAT_STIMER_DIRECT, 0),
> +    DEFINE_PROP_BIT64("hv-direct-tlbflush", X86CPU, hyperv_features,
> +                      HYPERV_FEAT_DIRECT_TLBFLUSH, 0),
>      DEFINE_PROP_BOOL("hv-passthrough", X86CPU, hyperv_passthrough, false),
>  
>      DEFINE_PROP_BOOL("check", X86CPU, check_cpuid, true),
> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> index eaa5395aa5..3cb105f7d6 100644
> --- a/target/i386/cpu.h
> +++ b/target/i386/cpu.h
> @@ -907,6 +907,7 @@ typedef uint64_t FeatureWordArray[FEATURE_WORDS];
>  #define HYPERV_FEAT_EVMCS               12
>  #define HYPERV_FEAT_IPI                 13
>  #define HYPERV_FEAT_STIMER_DIRECT       14
> +#define HYPERV_FEAT_DIRECT_TLBFLUSH     15
>  
>  #ifndef HYPERV_SPINLOCK_NEVER_RETRY
>  #define HYPERV_SPINLOCK_NEVER_RETRY             0xFFFFFFFF
> diff --git a/target/i386/kvm.c b/target/i386/kvm.c
> index 11b9c854b5..8e999dbcf1 100644
> --- a/target/i386/kvm.c
> +++ b/target/i386/kvm.c
> @@ -1235,6 +1235,27 @@ static int hyperv_handle_properties(CPUState *cs,
>          r |= 1;
>      }
>  
> +    if (hyperv_feat_enabled(cpu, HYPERV_FEAT_DIRECT_TLBFLUSH)) {
> +        if (!kvm_check_extension(cs->kvm_state,
> +            KVM_CAP_HYPERV_DIRECT_TLBFLUSH)) {
> +            fprintf(stderr,
> +                    "Kernel doesn't support Hyper-V direct tlbflush.\n");
> +            r = -ENOSYS;
> +            goto free;
> +        }
> +
> +        if (cpu->expose_kvm ||
> +            !hyperv_feat_enabled(cpu, HYPERV_FEAT_TLBFLUSH)) {
> +            fprintf(stderr, "Hyper-V direct tlbflush requires Hyper-V %s"
> +                    " and not expose KVM.\n",
> +                    kvm_hyperv_properties[HYPERV_FEAT_TLBFLUSH].desc);
> +            r = -ENOSYS;
> +            goto free;
> +        }
> +
> +        kvm_vcpu_enable_cap(cs, KVM_CAP_HYPERV_DIRECT_TLBFLUSH, 0, 0);
> +    }

We also have hv-passthrough mode where all Hyper-V enlightenments are
supposed to be enabled; I'd suggest you do the same we currently do with
HYPERV_FEAT_EVMCS:

    if (hyperv_feat_enabled(cpu, HYPERV_FEAT_DIRECT_TLBFLUSH) ||
        cpu->hyperv_passthrough) {

        r = kvm_vcpu_enable_cap(cs, KVM_CAP_HYPERV_DIRECT_TLBFLUSH, 0, 0);

        if (hyperv_feat_enabled(cpu, HYPERV_FEAT_EVMCS) && r) {
            fprintf(stderr, "Hyper-V %s is not supported by kernel\n",
                    kvm_hyperv_properties[HYPERV_FEAT_DIRECT_TLBFLUSH].desc);
            return -ENOSYS;
        }

No need to check for a capability if you're going to enable it right
away (and btw - this can fail).

You also need to use kvm_hyperv_properties to track dependencies between
features and not do it manually here (like you required
HYPERV_FEAT_TLBFLUSH). This is going to be the first feature without its
own CPUID bits assigned so some tweaks to kvm_hyperv_properties handling
may be required. Or we can use HYPERV_FEAT_TLBFLUSH bits, I'm not sure
here.


> +
>      /* Not exposed by KVM but needed to make CPU hotplug in Windows work */
>      env->features[FEAT_HYPERV_EDX] |= HV_CPU_DYNAMIC_PARTITIONING_AVAILABLE;

-- 
Vitaly

Re: [PATCH] target/i386/kvm: Add Hyper-V direct tlb flush support

[Tianyu Lan]

[-- Attachment #1: Type: text/plain, Size: 6883 bytes --]

Hi Vitaly:
                Thanks a lot for your review.
On Sun, Oct 13, 2019 at 4:49 PM Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
>
> lantianyu1986@gmail.com writes:
>
> > From: Tianyu Lan <Tianyu.Lan@microsoft.com>
> >
>
> (Please also Cc: Roman on you Hyper-V related submissions to QEMU who's
> known to be a great reviewer)

Good suggestion!
>
> > Hyper-V direct tlb flush targets KVM on Hyper-V guest.
> > Enable direct TLB flush for its guests meaning that TLB
> > flush hypercalls are handled by Level 0 hypervisor (Hyper-V)
> > bypassing KVM in Level 1. Due to the different ABI for hypercall
> > parameters between Hyper-V and KVM, KVM capabilities should be
> > hidden when enable Hyper-V direct tlb flush otherwise KVM
> > hypercalls may be intercepted by Hyper-V. Add new parameter
> > "hv-direct-tlbflush". Check expose_kvm and Hyper-V tlb flush
> > capability status before enabling the feature.
> >
> > Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
> > ---
> >  docs/hyperv.txt           | 12 ++++++++++++
> >  linux-headers/linux/kvm.h |  1 +
> >  target/i386/cpu.c         |  2 ++
> >  target/i386/cpu.h         |  1 +
> >  target/i386/kvm.c         | 21 +++++++++++++++++++++
> >  5 files changed, 37 insertions(+)
> >
> > diff --git a/docs/hyperv.txt b/docs/hyperv.txt
> > index 8fdf25c829..ceab8c21fe 100644
> > --- a/docs/hyperv.txt
> > +++ b/docs/hyperv.txt
> > @@ -184,6 +184,18 @@ enabled.
> >
> >  Requires: hv-vpindex, hv-synic, hv-time, hv-stimer
> >
> > +3.18. hv-direct-tlbflush
> > +=======================
> > +The enlightenment targets KVM on Hyper-V guest. Enable direct TLB flush for
> > +its guests meaning that TLB flush hypercalls are handled by Level 0 hypervisor
> > +(Hyper-V) bypassing KVM in Level 1. Due to the different ABI for hypercall
> > +parameters between Hyper-V and KVM, enabling this capability effectively
> > +disables all hypercall handling by KVM (as some KVM hypercall may be mistakenly
> > +treated as TLB flush hypercalls by Hyper-V). So kvm capability should not show
> > +to guest when enable this capability. If not, user will fail to enable this
> > +capability.
> > +
> > +Requires: hv-tlbflush, -kvm
> >
> >  4. Development features
> >  ========================
> > diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
> > index 18892d6541..923fb33a01 100644
> > --- a/linux-headers/linux/kvm.h
> > +++ b/linux-headers/linux/kvm.h
> > @@ -995,6 +995,7 @@ struct kvm_ppc_resize_hpt {
> >  #define KVM_CAP_ARM_SVE 170
> >  #define KVM_CAP_ARM_PTRAUTH_ADDRESS 171
> >  #define KVM_CAP_ARM_PTRAUTH_GENERIC 172
> > +#define KVM_CAP_HYPERV_DIRECT_TLBFLUSH 174
>
> I was once told that scripts/update-linux-headers.sh script is supposed
> to be used instead of cherry-picking stuff you need (adn this would be a
> separate patch - update linux headers to smth).
>

Thanks for suggestion. I just try the update-linux-headers.sh and there are a lot
of changes which are not related with my patch. I also include these
changes in my patch, right?

> >
> >  #ifdef KVM_CAP_IRQ_ROUTING
> >
> > diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> > index 44f1bbdcac..7bc7fee512 100644
> > --- a/target/i386/cpu.c
> > +++ b/target/i386/cpu.c
> > @@ -6156,6 +6156,8 @@ static Property x86_cpu_properties[] = {
> >                        HYPERV_FEAT_IPI, 0),
> >      DEFINE_PROP_BIT64("hv-stimer-direct", X86CPU, hyperv_features,
> >                        HYPERV_FEAT_STIMER_DIRECT, 0),
> > +    DEFINE_PROP_BIT64("hv-direct-tlbflush", X86CPU, hyperv_features,
> > +                      HYPERV_FEAT_DIRECT_TLBFLUSH, 0),
> >      DEFINE_PROP_BOOL("hv-passthrough", X86CPU, hyperv_passthrough, false),
> >
> >      DEFINE_PROP_BOOL("check", X86CPU, check_cpuid, true),
> > diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> > index eaa5395aa5..3cb105f7d6 100644
> > --- a/target/i386/cpu.h
> > +++ b/target/i386/cpu.h
> > @@ -907,6 +907,7 @@ typedef uint64_t FeatureWordArray[FEATURE_WORDS];
> >  #define HYPERV_FEAT_EVMCS               12
> >  #define HYPERV_FEAT_IPI                 13
> >  #define HYPERV_FEAT_STIMER_DIRECT       14
> > +#define HYPERV_FEAT_DIRECT_TLBFLUSH     15
> >
> >  #ifndef HYPERV_SPINLOCK_NEVER_RETRY
> >  #define HYPERV_SPINLOCK_NEVER_RETRY             0xFFFFFFFF
> > diff --git a/target/i386/kvm.c b/target/i386/kvm.c
> > index 11b9c854b5..8e999dbcf1 100644
> > --- a/target/i386/kvm.c
> > +++ b/target/i386/kvm.c
> > @@ -1235,6 +1235,27 @@ static int hyperv_handle_properties(CPUState *cs,
> >          r |= 1;
> >      }
> >
> > +    if (hyperv_feat_enabled(cpu, HYPERV_FEAT_DIRECT_TLBFLUSH)) {
> > +        if (!kvm_check_extension(cs->kvm_state,
> > +            KVM_CAP_HYPERV_DIRECT_TLBFLUSH)) {
> > +            fprintf(stderr,
> > +                    "Kernel doesn't support Hyper-V direct tlbflush.\n");
> > +            r = -ENOSYS;
> > +            goto free;
> > +        }
> > +
> > +        if (cpu->expose_kvm ||
> > +            !hyperv_feat_enabled(cpu, HYPERV_FEAT_TLBFLUSH)) {
> > +            fprintf(stderr, "Hyper-V direct tlbflush requires Hyper-V %s"
> > +                    " and not expose KVM.\n",
> > +                    kvm_hyperv_properties[HYPERV_FEAT_TLBFLUSH].desc);
> > +            r = -ENOSYS;
> > +            goto free;
> > +        }
> > +
> > +        kvm_vcpu_enable_cap(cs, KVM_CAP_HYPERV_DIRECT_TLBFLUSH, 0, 0);
> > +    }
>
> We also have hv-passthrough mode where all Hyper-V enlightenments are
> supposed to be enabled; I'd suggest you do the same we currently do with
> HYPERV_FEAT_EVMCS:
>
>     if (hyperv_feat_enabled(cpu, HYPERV_FEAT_DIRECT_TLBFLUSH) ||
>         cpu->hyperv_passthrough) {
>
>         r = kvm_vcpu_enable_cap(cs, KVM_CAP_HYPERV_DIRECT_TLBFLUSH, 0, 0);
>
>         if (hyperv_feat_enabled(cpu, HYPERV_FEAT_EVMCS) && r) {
>             fprintf(stderr, "Hyper-V %s is not supported by kernel\n",
>                     kvm_hyperv_properties[HYPERV_FEAT_DIRECT_TLBFLUSH].desc);
>             return -ENOSYS;
>         }
>
> No need to check for a capability if you're going to enable it right
> away (and btw - this can fail).
>

Nice catch.  I ignored passthrough mode and will update in the new version.

> You also need to use kvm_hyperv_properties to track dependencies between
> features and not do it manually here (like you required
> HYPERV_FEAT_TLBFLUSH). This is going to be the first feature without its
> own CPUID bits assigned so some tweaks to kvm_hyperv_properties handling
> may be required. Or we can use HYPERV_FEAT_TLBFLUSH bits, I'm not sure
> here.
>

Yes,  I found kvm_hyperv_properties didn't support no CPUID case and so gave up
to use it. I will have a try in the next version. Thanks.
--
Best regards
Tianyu Lan

[-- Attachment #2: Type: text/html, Size: 12912 bytes --]

Re: [PATCH] target/i386/kvm: Add Hyper-V direct tlb flush support

[Cornelia Huck]

On Mon, 14 Oct 2019 13:29:12 +0000
Tianyu Lan <Tianyu.Lan@microsoft.com> wrote:

> > > diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
> > > index 18892d6541..923fb33a01 100644
> > > --- a/linux-headers/linux/kvm.h
> > > +++ b/linux-headers/linux/kvm.h
> > > @@ -995,6 +995,7 @@ struct kvm_ppc_resize_hpt {
> > >  #define KVM_CAP_ARM_SVE 170
> > >  #define KVM_CAP_ARM_PTRAUTH_ADDRESS 171
> > >  #define KVM_CAP_ARM_PTRAUTH_GENERIC 172
> > > +#define KVM_CAP_HYPERV_DIRECT_TLBFLUSH 174  
> >
> > I was once told that scripts/update-linux-headers.sh script is supposed
> > to be used instead of cherry-picking stuff you need (adn this would be a
> > separate patch - update linux headers to smth).
> >  
> 
> Thanks for suggestion. I just try the update-linux-headers.sh and there are a lot
> of changes which are not related with my patch. I also include these
> changes in my patch, right?

The important part is that you split out the headers update as a
separate patch.

If this change is already included in the upstream kernel, just do a
complete update via the script (mentioning the base you did the update
against.) If not, include a placeholder patch that can be replaced by a
real update when applying.

RE: [PATCH] target/i386/kvm: Add Hyper-V direct tlb flush support

[Tianyu Lan]

On Mon, Oct 14, 2019 at 9:48 PM Cornelia Huck <cohuck@redhat.com> wrote:
>
> On Mon, 14 Oct 2019 13:29:12 +0000
> Tianyu Lan <Tianyu.Lan@microsoft.com> wrote:
>
> > > > diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
> > > > index 18892d6541..923fb33a01 100644
> > > > --- a/linux-headers/linux/kvm.h
> > > > +++ b/linux-headers/linux/kvm.h
> > > > @@ -995,6 +995,7 @@ struct kvm_ppc_resize_hpt {
> > > >  #define KVM_CAP_ARM_SVE 170
> > > >  #define KVM_CAP_ARM_PTRAUTH_ADDRESS 171
> > > >  #define KVM_CAP_ARM_PTRAUTH_GENERIC 172
> > > > +#define KVM_CAP_HYPERV_DIRECT_TLBFLUSH 174 
> > >
> > > I was once told that scripts/update-linux-headers.sh script is supposed
> > > to be used instead of cherry-picking stuff you need (adn this would be a
> > > separate patch - update linux headers to smth).
> > > 
> >
> > Thanks for suggestion. I just try the update-linux-headers.sh and there are a lot
> > of changes which are not related with my patch. I also include these
> > changes in my patch, right?
>
> The important part is that you split out the headers update as a
> separate patch.
>
> If this change is already included in the upstream kernel, just do a
> complete update via the script (mentioning the base you did the update
> against.) If not, include a placeholder patch that can be replaced by a
> real update when applying.

OK. This change has been upstreamed and I will send complete update patch. Thanks.

-- 
Best regards
Tianyu Lan

Re: [PATCH] target/i386/kvm: Add Hyper-V direct tlb flush support

[Vitaly Kuznetsov]

Tianyu Lan <Tianyu.Lan@microsoft.com> writes:

>> > --- a/linux-headers/linux/kvm.h
>> > +++ b/linux-headers/linux/kvm.h
>> > @@ -995,6 +995,7 @@ struct kvm_ppc_resize_hpt {
>> >  #define KVM_CAP_ARM_SVE 170
>> >  #define KVM_CAP_ARM_PTRAUTH_ADDRESS 171
>> >  #define KVM_CAP_ARM_PTRAUTH_GENERIC 172
>> > +#define KVM_CAP_HYPERV_DIRECT_TLBFLUSH 174
>>
>> I was once told that scripts/update-linux-headers.sh script is supposed
>> to be used instead of cherry-picking stuff you need (adn this would be a
>> separate patch - update linux headers to smth).
>>
>
> Thanks for suggestion. I just try the update-linux-headers.sh and there are a lot
> of changes which are not related with my patch. I also include these
> changes in my patch, right?
>

Yes, see e.g.

commit d9cb4336159a00bd0d9c81b93f02874ef3626057
Author: Cornelia Huck <cohuck@redhat.com>
Date:   Thu May 16 19:10:36 2019 +0200

    linux headers: update against Linux 5.2-rc1

as an example.

-- 
Vitaly