linux-kernel - Re: [PATCH v4 4/4] KVM: SVM: Return -EINVAL instead of -EBUSY on attempt to re-init SEV/SEV-ES

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Message-ID: <41b47702-6e65-439c-aa0d-bf47647e33c6@amd.com>
Date: Thu, 1 Feb 2024 10:32:37 -0600
From: Tom Lendacky <thomas.lendacky@....com>
To: Sean Christopherson <seanjc@...gle.com>,
 Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
 Ashish Kalra <ashish.kalra@....com>
Subject: Re: [PATCH v4 4/4] KVM: SVM: Return -EINVAL instead of -EBUSY on
 attempt to re-init SEV/SEV-ES

On 1/31/24 17:56, Sean Christopherson wrote:
> Return -EINVAL instead of -EBUSY if userspace attempts KVM_SEV{,ES}_INIT
> on a VM that already has SEV active.  Returning -EBUSY is nonsencial as
> it's impossible to deactivate SEV without destroying the VM, i.e. the VM
> isn't "busy" in any sane sense of the word, and the odds of any userspace
> wanting exactly -EBUSY on a userspace bug are minuscule.
> 
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>

Reviewed-by: Tom Lendacky <thomas.lendacky@....com>

> ---
>   arch/x86/kvm/svm/sev.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index 38e40fbc7ea0..cb19b57e1031 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c
> @@ -259,9 +259,8 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
>   	if (kvm->created_vcpus)
>   		return -EINVAL;
>   
> -	ret = -EBUSY;
>   	if (unlikely(sev->active))
> -		return ret;
> +		return -EINVAL;
>   
>   	sev->active = true;
>   	sev->es_active = argp->id == KVM_SEV_ES_INIT;