linux-kernel - Re: [PATCH 4/4] KVM: x86: Hyper-V tsc page setup

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Message-ID: <20160919163812.GC11067@rkaganb.sw.ru>
Date:   Mon, 19 Sep 2016 19:38:12 +0300
From:   Roman Kagan <rkagan@...tuozzo.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
CC:     <linux-kernel@...r.kernel.org>, <kvm@...r.kernel.org>,
        <rkrcmar@...hat.com>, <den@...nvz.org>, <peterhornyack@...gle.com>,
        "Andrey Smetanin" <asmetanin@...tuozzo.com>
Subject: Re: [PATCH 4/4] KVM: x86: Hyper-V tsc page setup

On Mon, Sep 19, 2016 at 01:39:13PM +0200, Paolo Bonzini wrote:
> Lately tsc page was implemented but filled with empty
> values. This patch setup tsc page scale and offset based
> on vcpu tsc, tsc_khz and  HV_X64_MSR_TIME_REF_COUNT value.
> 
> The valid tsc page drops HV_X64_MSR_TIME_REF_COUNT msr
> reads count to zero which potentially improves performance.
> 
> Signed-off-by: Andrey Smetanin <asmetanin@...tuozzo.com>
> Reviewed-by: Peter Hornyack <peterhornyack@...gle.com>
> CC: Paolo Bonzini <pbonzini@...hat.com>
> CC: Radim Krčmář <rkrcmar@...hat.com>
> CC: Roman Kagan <rkagan@...tuozzo.com>
> CC: Denis V. Lunev <den@...nvz.org>
> [Computation of TSC page parameters rewritten to use the Linux timekeeper
>  parameters. - Paolo]
> Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
> ---
>  arch/x86/include/asm/kvm_host.h |   2 +
>  arch/x86/kvm/hyperv.c           | 162 ++++++++++++++++++++++++++++++++++++----
>  arch/x86/kvm/hyperv.h           |   3 +
>  arch/x86/kvm/x86.c              |   8 +-
>  4 files changed, 155 insertions(+), 20 deletions(-)

Reviewed-by: Roman Kagan <rkagan@...tuozzo.com>