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Date:   Thu, 8 Sep 2022 11:21:19 -0700
From:   Isaku Yamahata <isaku.yamahata@gmail.com>
To:     Yuan Yao <yuan.yao@linux.intel.com>
Cc:     isaku.yamahata@intel.com, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <seanjc@google.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Marc Zyngier <maz@kernel.org>, Will Deacon <will@kernel.org>,
        isaku.yamahata@gmail.com, Kai Huang <kai.huang@intel.com>,
        Chao Gao <chao.gao@intel.com>,
        Atish Patra <atishp@atishpatra.org>,
        Shaokun Zhang <zhangshaokun@hisilicon.com>,
        Qi Liu <liuqi115@huawei.com>,
        John Garry <john.garry@huawei.com>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Huang Ying <ying.huang@intel.com>,
        Huacai Chen <chenhuacai@kernel.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Borislav Petkov <bp@alien8.de>
Subject: Re: [PATCH v3 09/22] KVM: Do processor compatibility check on resume
Message-ID: <20220908182119.GA470011@ls.amr.corp.intel.com>
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On Mon, Sep 05, 2022 at 05:27:12PM +0800,
Yuan Yao <yuan.yao@linux.intel.com> wrote:

> On Mon, Sep 05, 2022 at 04:40:14PM +0800, Yuan Yao wrote:
> > On Thu, Sep 01, 2022 at 07:17:44PM -0700, isaku.yamahata@intel.com wrote:
> > > From: Isaku Yamahata <isaku.yamahata@intel.com>
> > >
> > > So far the processor compatibility check is not done on resume. It should
> > > be done.
> >
> > The resume happens for resuming from S3/S4, so the compatibility
> > checking is used to detecte CPU replacement, or resume from S4 on an
> > different machine ?
> 
> By did experiments, I found the resume is called once on CPU 0 before
> other CPUs come UP, so yes it's necessary to check it.

I've added the commit message.

    KVM: Do processor compatibility check on resume
    
    So far the processor compatibility check is not done on resume. It should
    be done.  The resume is called for resuming from S3/S4.  CPUs can be
    replaced or the kernel can resume from S4 on a different machine.  So
    compatibility check is desirable.

-- 
Isaku Yamahata <isaku.yamahata@gmail.com>