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AFNElJ9o4l5rpYNRJGTrvRg5u9wADgECDi6XJvBk54/7SbAsp7UYQ+GHaq7igIpZ3ZIUXabxxV0=@vger.kernel.org X-Gm-Message-State: AOJu0YyTqU99N3yXAKA3Ct8ujwgwDodHbHRahdN2gJ8n8vHev8H+Y+sJ Ag96SNwLa4+CyVQllAsm6R1ZikRp69DbdOxEbhz0i0lcak2jqWEU7xzBZSAdPLyFy2Ty+qPjoad 3irxb+A== X-Received: from pjbfh16.prod.google.com ([2002:a17:90b:350:b0:36b:c7cb:baf]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:58e7:b0:36b:936e:73c8 with SMTP id 98e67ed59e1d1-370f0e4ad33mr20840879a91.19.1780965086844; Mon, 08 Jun 2026 17:31:26 -0700 (PDT) Date: Mon, 8 Jun 2026 17:31:26 -0700 In-Reply-To: <20260530070848.158521F00893@smtp.kernel.org> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260529144435.704127-27-seanjc@google.com> <20260530070848.158521F00893@smtp.kernel.org> Message-ID: Subject: Re: [PATCH v4 26/47] x86/kvm: Don't disable kvmclock on BSP in syscore_suspend() From: Sean Christopherson To: sashiko-reviews@lists.linux.dev Cc: linux-hyperv@vger.kernel.org, kvm@vger.kernel.org Content-Type: text/plain; charset="us-ascii" On Sat, May 30, 2026, sashiko-bot@kernel.org wrote: > > diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c > > index c81a24d0efdf6..fd1c417b4f9b9 100644 > > --- a/arch/x86/kernel/kvm.c > > +++ b/arch/x86/kernel/kvm.c > > @@ -460,7 +460,7 @@ static void __init sev_map_percpu_data(void) > > [ ... ] > > > -static void kvm_guest_cpu_offline(bool shutdown) > > +static void kvm_guest_cpu_offline(enum kvm_guest_cpu_action action) > > { > > kvm_disable_steal_time(); > > if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) > > @@ -468,9 +468,10 @@ static void kvm_guest_cpu_offline(bool shutdown) > > if (kvm_para_has_feature(KVM_FEATURE_MIGRATION_CONTROL)) > > wrmsrq(MSR_KVM_MIGRATION_CONTROL, 0); > > [Severity: High] > This isn't a bug introduced by this patch, but I noticed that > MSR_KVM_MIGRATION_CONTROL is cleared to 0 here during CPU offline and system > suspend, but it does not appear to be re-enabled upon online/resume. > > Since this patch introduces the kvm_guest_cpu_action enum to solve an > identical state-machine issue for kvmclock, should we also use this action > enum to ensure the migration control MSR isn't incorrectly cleared on > suspend? Otherwise, wouldn't a single CPU hotplug event or a suspend/resume > cycle permanently disable live migration for the entire VM? Looks like. That's someone else's future problem though.