From mboxrd@z Thu Jan  1 00:00:00 1970
From: Vitaly Kuznetsov <vkuznets@redhat.com>
Subject: Re: [PATCH v2 0/7] x86/kvm/hyperv: stable clocksorce for L2 guests when running nested KVM on Hyper-V
Date: Fri, 15 Dec 2017 10:30:54 +0100
Message-ID: <87r2rw2v8x.fsf@vitty.brq.redhat.com>
References: <20171213150945.24054-1-vkuznets@redhat.com>
        <e9d2f20a-178f-a42e-d1e3-7396c04315bb@redhat.com>
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Cc: kvm@vger.kernel.org, x86@kernel.org,
        Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@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>,
        Andy Lutomirski <luto@kernel.org>,
        Mohammed Gamal <mmorsy@redhat.com>,
        Cathy Avery <cavery@redhat.com>,
        Roman Kagan <rkagan@virtuozzo.com>,
        linux-kernel@vger.kernel.org, devel@linuxdriverproject.org
To: Paolo Bonzini <pbonzini@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>
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In-Reply-To: <e9d2f20a-178f-a42e-d1e3-7396c04315bb@redhat.com> (Paolo
        Bonzini's message of "Fri, 15 Dec 2017 10:01:06 +0100")
Sender: linux-kernel-owner@vger.kernel.org
List-Id: kvm.vger.kernel.org

Paolo Bonzini <pbonzini@redhat.com> writes:

> On 13/12/2017 16:09, Vitaly Kuznetsov wrote:
>> Currently, KVM passes PVCLOCK_TSC_STABLE_BIT to its guests when running in
>> so called 'masterclock' mode and this is only possible when the clocksource
>> on the host is TSC. When running nested on Hyper-V we're using a different
>> clocksource in L1 (Hyper-V TSC Page) which can actually be used for
>> masterclock. This series brings the required support.
>> 
>> Making KVM work with TSC page clocksource is relatively easy, it is done in
>> PATCH 5 of the series. All the rest is required to support L1 migration
>   ^^^^^^^
>
> Patch 6. :)
>

Off-by-one :-)

>> when TSC frequency changes, we use a special feature from Hyper-V to do
>> the job.
>
> Patches 5-7 are
>
> Acked-by: Paolo Bonzini <pbonzini@redhat.com>
>

Thanks!

> I would appreciate if the Hyper-V folks can provide a topic branch to be
> merged in both HV and KVM trees.
>

There's no such thing as Hyper-V tree, patches are usually getting
merged through 'tip' tree when the majority of changes go to arch/x86 or
Greg's char-misc tree when changes are drivers/hv heavy (+ net, scsi,
pci, hid, ... trees for individual drivers).

In this particular case the series is x86-heavy and I believe it should
go through x86 'tip' tree.

Thomas, Ingo, Peter, could you please take a look? Thanks!

-- 
  Vitaly