linux-kernel - Re: [PATCH v3 1/3] KVM: LAPIC: Prevent setting the tscdeadline timer if the lapic is hw disabled

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Message-ID: <f28c7ad5-ea17-382e-f61e-c48418e49363@redhat.com>
Date:   Fri, 31 Jul 2020 09:18:33 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Wanpeng Li <kernellwp@...il.com>, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org
Cc:     Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, stable@...r.kernel.org
Subject: Re: [PATCH v3 1/3] KVM: LAPIC: Prevent setting the tscdeadline timer
 if the lapic is hw disabled

On 31/07/20 05:12, Wanpeng Li wrote:
> From: Wanpeng Li <wanpengli@...cent.com>
> 
> Prevent setting the tscdeadline timer if the lapic is hw disabled.
> 
> Fixes: bce87cce88 (KVM: x86: consolidate different ways to test for in-kernel LAPIC)
> Cc: <stable@...r.kernel.org>
> Signed-off-by: Wanpeng Li <wanpengli@...cent.com>
> ---
> v1 -> v2:
>  * add Fixes tag and cc stable
> 
>  arch/x86/kvm/lapic.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index 5bf72fc..4ce2ddd 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -2195,7 +2195,7 @@ void kvm_set_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu, u64 data)
>  {
>  	struct kvm_lapic *apic = vcpu->arch.apic;
>  
> -	if (!lapic_in_kernel(vcpu) || apic_lvtt_oneshot(apic) ||
> +	if (!kvm_apic_present(vcpu) || apic_lvtt_oneshot(apic) ||
>  			apic_lvtt_period(apic))
>  		return;
>  
> 

Testcase please.

Paolo