From: "Radim Krčmář" <rkrcmar@redhat.com>
To: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: kvm@vger.kernel.org, x86@kernel.org,
Paolo Bonzini <pbonzini@redhat.com>,
"K. Y. Srinivasan" <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
"Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com>,
Mohammed Gamal <mmorsy@redhat.com>,
Cathy Avery <cavery@redhat.com>, Bandan Das <bsd@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Christoph Hellwig <hch@infradead.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 7/7] x86/kvm: use Enlightened VMCS when running on Hyper-V
Date: Fri, 16 Mar 2018 17:06:09 +0100 [thread overview]
Message-ID: <20180316160609.GD5180@flask> (raw)
In-Reply-To: <20180316142220.32506-8-vkuznets@redhat.com>
2018-03-16 15:22+0100, Vitaly Kuznetsov:
> Enlightened VMCS is just a structure in memory, the main benefit
> besides avoiding somewhat slower VMREAD/VMWRITE is using clean field
> mask: we tell the underlying hypervisor which fields were modified
> since VMEXIT so there's no need to inspect them all.
>
> Tight CPUID loop test shows significant speedup:
> Before: 18890 cycles
> After: 8304 cycles
>
> Static key is being used to avoid performance penalty for non-Hyper-V
> deployments.
>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
Looks good, thanks.
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
next prev parent reply other threads:[~2018-03-16 16:06 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-16 14:22 [PATCH v4 0/7] Enlightened VMCS support for KVM on Hyper-V Vitaly Kuznetsov
2018-03-16 14:22 ` [PATCH v4 1/7] x86/hyper-v: move hyperv.h out of uapi Vitaly Kuznetsov
2018-03-16 14:22 ` [PATCH v4 2/7] x86/hyper-v: move definitions from TLFS to hyperv-tlfs.h Vitaly Kuznetsov
2018-03-16 14:22 ` [PATCH v4 3/7] x86/kvm: rename HV_X64_MSR_APIC_ASSIST_PAGE to HV_X64_MSR_VP_ASSIST_PAGE Vitaly Kuznetsov
2018-03-16 14:22 ` [PATCH v4 4/7] x86/hyper-v: allocate and use Virtual Processor Assist Pages Vitaly Kuznetsov
2018-03-18 15:42 ` Thomas Gleixner
2018-03-16 14:22 ` [PATCH v4 5/7] x86/hyper-v: define struct hv_enlightened_vmcs and clean field bits Vitaly Kuznetsov
2018-03-16 14:22 ` [PATCH v4 6/7] x86/hyper-v: detect nested features Vitaly Kuznetsov
2018-03-18 15:46 ` Thomas Gleixner
2018-03-18 15:47 ` Thomas Gleixner
2018-03-16 14:22 ` [PATCH v4 7/7] x86/kvm: use Enlightened VMCS when running on Hyper-V Vitaly Kuznetsov
2018-03-16 16:06 ` Radim Krčmář [this message]
2018-03-18 15:49 ` [PATCH v4 0/7] Enlightened VMCS support for KVM " Thomas Gleixner
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