Re: [PATCH v2 4/4] KVM: hyper-v: Advertise support for fast XMM hypercalls

From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: Siddharth Chandrasekaran <sidcha@amazon.de>
Cc: Alexander Graf <graf@amazon.com>,
	Evgeny Iakovlev <eyakovl@amazon.de>,
	Liran Alon <liran@amazon.com>,
	Ioannis Aslanidis <iaslan@amazon.de>,
	linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org,
	kvm@vger.kernel.org, "K. Y. Srinivasan" <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	Wei Liu <wei.liu@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>
Subject: Re: [PATCH v2 4/4] KVM: hyper-v: Advertise support for fast XMM hypercalls
Date: Tue, 13 Apr 2021 16:26:52 +0200	[thread overview]
Message-ID: <87pmyy5kgj.fsf@vitty.brq.redhat.com> (raw)
In-Reply-To: <5ec20918b06cad17cb43f04be212c5e21c18caea.1618244920.git.sidcha@amazon.de>

Siddharth Chandrasekaran <sidcha@amazon.de> writes:

> Now that all extant hypercalls that can use XMM registers (based on
> spec) for input/outputs are patched to support them, we can start
> advertising this feature to guests.
>
> Cc: Alexander Graf <graf@amazon.com>
> Cc: Evgeny Iakovlev <eyakovl@amazon.de>
> Signed-off-by: Siddharth Chandrasekaran <sidcha@amazon.de>
> ---
>  arch/x86/include/asm/hyperv-tlfs.h | 7 ++++++-
>  arch/x86/kvm/hyperv.c              | 2 ++
>  2 files changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
> index e6cd3fee562b..716f12be411e 100644
> --- a/arch/x86/include/asm/hyperv-tlfs.h
> +++ b/arch/x86/include/asm/hyperv-tlfs.h
> @@ -52,7 +52,7 @@
>   * Support for passing hypercall input parameter block via XMM
>   * registers is available
>   */
> -#define HV_X64_HYPERCALL_PARAMS_XMM_AVAILABLE		BIT(4)
> +#define HV_X64_HYPERCALL_XMM_INPUT_AVAILABLE		BIT(4)
>  /* Support for a virtual guest idle state is available */
>  #define HV_X64_GUEST_IDLE_STATE_AVAILABLE		BIT(5)
>  /* Frequency MSRs available */
> @@ -61,6 +61,11 @@
>  #define HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE		BIT(10)
>  /* Support for debug MSRs available */
>  #define HV_FEATURE_DEBUG_MSRS_AVAILABLE			BIT(11)
> +/*
> + * Support for returning hypercall ouput block via XMM
> + * registers is available
> + */
> +#define HV_X64_HYPERCALL_XMM_OUTPUT_AVAILABLE		BIT(15)
>  /* stimer Direct Mode is available */
>  #define HV_STIMER_DIRECT_MODE_AVAILABLE			BIT(19)
>  
> diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
> index 1f9959aba70d..55838c266bcd 100644
> --- a/arch/x86/kvm/hyperv.c
> +++ b/arch/x86/kvm/hyperv.c
> @@ -2254,6 +2254,8 @@ int kvm_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid,
>  			ent->ebx |= HV_POST_MESSAGES;
>  			ent->ebx |= HV_SIGNAL_EVENTS;
>  
> +			ent->edx |= HV_X64_HYPERCALL_XMM_INPUT_AVAILABLE;
> +			ent->edx |= HV_X64_HYPERCALL_XMM_OUTPUT_AVAILABLE;
>  			ent->edx |= HV_FEATURE_FREQUENCY_MSRS_AVAILABLE;
>  			ent->edx |= HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE;

With 'ouput' typo fixed,

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>

-- 
Vitaly