linux-kernel - Re: [PATCH v2 02/22] KVM: SVM: leave halted state on vmexit

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Message-ID: <20200424174150.GA224300@google.com>
Date:   Fri, 24 Apr 2020 17:41:50 +0000
From:   Oliver Upton <oupton@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        wei.huang2@....com, cavery@...hat.com, vkuznets@...hat.com,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Jim Mattson <jmattson@...gle.com>
Subject: Re: [PATCH v2 02/22] KVM: SVM: leave halted state on vmexit

On Fri, Apr 24, 2020 at 01:23:56PM -0400, Paolo Bonzini wrote:
> Similar to VMX, we need to leave the halted state when performing a vmexit.
> Failure to do so will cause a hang after vmexit.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Reviewed-by: Oliver Upton <oupton@...gle.com>
> ---
>  arch/x86/kvm/svm/nested.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
> index 51cfab68428d..e69e60ac1370 100644
> --- a/arch/x86/kvm/svm/nested.c
> +++ b/arch/x86/kvm/svm/nested.c
> @@ -472,6 +472,9 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
>  	leave_guest_mode(&svm->vcpu);
>  	svm->nested.vmcb = 0;
>  
> +	/* in case we halted in L2 */
> +	svm->vcpu.arch.mp_state = KVM_MP_STATE_RUNNABLE;
> +
>  	/* Give the current vmcb to the guest */
>  	disable_gif(svm);
>  
> -- 
> 2.18.2
> 
>