linux-kernel - Re: [PATCH v2 2/8] KVM: SVM: Open code handling of unexpected exits in svm_invoke_exit

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Message-ID: <da6851da-979d-4c7a-9e19-08885f3ae042@amd.com>
Date: Fri, 2 Jan 2026 12:41:06 +0100
From: "Gupta, Pankaj" <pankaj.gupta@....com>
To: Sean Christopherson <seanjc@...gle.com>,
 Paolo Bonzini <pbonzini@...hat.com>, Vitaly Kuznetsov <vkuznets@...hat.com>,
 "K. Y. Srinivasan" <kys@...rosoft.com>,
 Haiyang Zhang <haiyangz@...rosoft.com>, Wei Liu <wei.liu@...nel.org>,
 Dexuan Cui <decui@...rosoft.com>, Long Li <longli@...rosoft.com>
Cc: kvm@...r.kernel.org, linux-hyperv@...r.kernel.org,
 linux-kernel@...r.kernel.org, Jim Mattson <jmattson@...gle.com>,
 Yosry Ahmed <yosry.ahmed@...ux.dev>
Subject: Re: [PATCH v2 2/8] KVM: SVM: Open code handling of unexpected exits
 in svm_invoke_exit_handler()


> Fold svm_check_exit_valid() and svm_handle_invalid_exit() into their sole
> caller, svm_invoke_exit_handler(), as having tiny single-use helpers makes
> the code unncessarily difficult to follow.  This will also allow for
> additional cleanups in svm_invoke_exit_handler().
>
> No functional change intended.
>
> Suggested-by: Yosry Ahmed <yosry.ahmed@...ux.dev>
> Reviewed-by: Yosry Ahmed <yosry.ahmed@...ux.dev>
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>

Reviewed-by: Pankaj Gupta <pankaj.gupta@....com>

> ---
>   arch/x86/kvm/svm/svm.c | 25 ++++++++++---------------
>   1 file changed, 10 insertions(+), 15 deletions(-)
>
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index c2ddf2e0aa1a..a523011f0923 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -3443,23 +3443,13 @@ static void dump_vmcb(struct kvm_vcpu *vcpu)
>   		sev_free_decrypted_vmsa(vcpu, save);
>   }
>   
> -static bool svm_check_exit_valid(u64 exit_code)
> -{
> -	return (exit_code < ARRAY_SIZE(svm_exit_handlers) &&
> -		svm_exit_handlers[exit_code]);
> -}
> -
> -static int svm_handle_invalid_exit(struct kvm_vcpu *vcpu, u64 exit_code)
> -{
> -	dump_vmcb(vcpu);
> -	kvm_prepare_unexpected_reason_exit(vcpu, exit_code);
> -	return 0;
> -}
> -
>   int svm_invoke_exit_handler(struct kvm_vcpu *vcpu, u64 exit_code)
>   {
> -	if (!svm_check_exit_valid(exit_code))
> -		return svm_handle_invalid_exit(vcpu, exit_code);
> +	if (exit_code >= ARRAY_SIZE(svm_exit_handlers))
> +		goto unexpected_vmexit;
> +
> +	if (!svm_exit_handlers[exit_code])
> +		goto unexpected_vmexit;
>   
>   #ifdef CONFIG_MITIGATION_RETPOLINE
>   	if (exit_code == SVM_EXIT_MSR)
> @@ -3478,6 +3468,11 @@ int svm_invoke_exit_handler(struct kvm_vcpu *vcpu, u64 exit_code)
>   #endif
>   #endif
>   	return svm_exit_handlers[exit_code](vcpu);
> +
> +unexpected_vmexit:
> +	dump_vmcb(vcpu);
> +	kvm_prepare_unexpected_reason_exit(vcpu, exit_code);
> +	return 0;
>   }
>   
>   static void svm_get_exit_info(struct kvm_vcpu *vcpu, u32 *reason,