linux-kernel - Re: [PATCH v2 2/2] KVM: SVM: enhance info printk's in SEV init

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Date:   Tue, 6 Jun 2023 11:46:38 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Alexander Mikhalitsyn <aleksandr.mikhalitsyn@...onical.com>
Cc:     pbonzini@...hat.com,
        "Stéphane Graber" <stgraber@...ntu.com>,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        "H. Peter Anvin" <hpa@...or.com>
Subject: Re: [PATCH v2 2/2] KVM: SVM: enhance info printk's in SEV init

On Mon, May 22, 2023, Alexander Mikhalitsyn wrote:
> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index cc832a8d1bca..fff63d1f2a34 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c
> @@ -2224,7 +2224,6 @@ void __init sev_hardware_setup(void)
>  		goto out;
>  	}
>  
> -	pr_info("SEV supported: %u ASIDs\n", sev_asid_count);
>  	sev_supported = true;
>  
>  	/* SEV-ES support requested? */
> @@ -2252,10 +2251,16 @@ void __init sev_hardware_setup(void)
>  	if (misc_cg_set_capacity(MISC_CG_RES_SEV_ES, sev_es_asid_count))
>  		goto out;
>  
> -	pr_info("SEV-ES supported: %u ASIDs\n", sev_es_asid_count);
>  	sev_es_supported = true;
>  
>  out:
> +	if (boot_cpu_has(X86_FEATURE_SEV))
> +		pr_info("SEV %s (ASIDs %u - %u)\n",
> +			sev_supported ? "enabled" : "disabled", min_sev_asid, max_sev_asid);
> +	if (boot_cpu_has(X86_FEATURE_SEV_ES))
> +		pr_info("SEV-ES %s (ASIDs %u - %u)\n",
> +			sev_es_supported ? "enabled" : "disabled", 1, min_sev_asid - 1);

The min should print '0' if min_sev_asid<=1, otherwise the output will be

	SEV-ES disabled (ASIDs 1 - 0)

which is confusing.  That would also align with what gets printed out for SEV
when it's not supported at all (min==max=0).

No need for v3, I'll fixup when applying.