linux-kernel - Re: [PATCH 0/2] KVM: x86: Revert to fix apic_hw

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Date:   Fri, 15 Oct 2021 11:02:35 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Sean Christopherson <seanjc@...gle.com>
Cc:     Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        syzbot+9fc046ab2b0cf295a063@...kaller.appspotmail.com,
        Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>
Subject: Re: [PATCH 0/2] KVM: x86: Revert to fix apic_hw_disabled underflow

On 13/10/21 02:35, Sean Christopherson wrote:
> Revert (mostly) a patch from the vCPU RESET cleanup that open coded some
> APIC shenanigans to avoid stuffing vcpu->arch.apic_base at vCPU creation,
> and completely overlooked the side effects on apic_hw_disabled.  I went
> for a revert as I think the original behavior is the least awful solution,
> just somewhat poorly documented.
> 
> The second patch adds WARNs to detect "overflow", where "overflow" means
> KVM incorrectly increments apic_hw_disabled.
> 
> Sean Christopherson (2):
>    Revert "KVM: x86: Open code necessary bits of kvm_lapic_set_base() at
>      vCPU RESET"
>    KVM: x86: WARN if APIC HW/SW disable static keys are non-zero on
>      unload
> 
>   arch/x86/kvm/lapic.c | 20 +++++++++++++-------
>   1 file changed, 13 insertions(+), 7 deletions(-)
> 

Queued for 5.15, thanks.

Paolo