linux-kernel - Re: [PATCH v3 07/10] KVM: nVMX: Switch to vmcs01 to refresh APICv controls on-demand if L2 is active

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Message-ID: <aU3oydjd+1fp3Exv@intel.com>
Date: Fri, 26 Dec 2025 09:45:45 +0800
From: Chao Gao <chao.gao@...el.com>
To: Sean Christopherson <seanjc@...gle.com>
CC: Paolo Bonzini <pbonzini@...hat.com>, <kvm@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, Dongli Zhang <dongli.zhang@...cle.com>
Subject: Re: [PATCH v3 07/10] KVM: nVMX: Switch to vmcs01 to refresh APICv
 controls on-demand if L2 is active

On Fri, Dec 05, 2025 at 03:19:10PM -0800, Sean Christopherson wrote:
>If APICv is (un)inhibited while L2 is running, temporarily load vmcs01 and
>immediately refresh the APICv controls in vmcs01 instead of deferring the
>update until the next nested VM-Exit.  This all but eliminates potential
>ordering issues due to vmcs01 not being synchronized with
>kvm_lapic.apicv_active, e.g. where KVM _thinks_ it refreshed APICv, but
>vmcs01 still contains stale state.
>
>Signed-off-by: Sean Christopherson <seanjc@...gle.com>

Reviewed-by: Chao Gao <chao.gao@...el.com>