Re: [RFC PATCH v2 2/5] KVM: SVM: Simplify the message printed with 'force_avic'

[Sean Christopherson <seanjc@google.com>]

On Thu, Sep 04, 2025, Naveen N Rao (AMD) wrote:
> On systems that do not advertise support for AVIC, it can be
> force-enabled through 'force_avic' module parameter. In that case, a
> warning is displayed but the customary "AVIC enabled" message isn't.
> Fix that by printing "AVIC enabled" unconditionally. The warning for
> 'force_avic' is also needlessly long. Simplify the same.
> 
> Signed-off-by: Naveen N Rao (AMD) <naveen@kernel.org>
> ---
>  arch/x86/kvm/svm/avic.c | 12 ++----------
>  1 file changed, 2 insertions(+), 10 deletions(-)
> 
> diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
> index 346cd23a43a9..3faed85fcacd 100644
> --- a/arch/x86/kvm/svm/avic.c
> +++ b/arch/x86/kvm/svm/avic.c
> @@ -1110,16 +1110,8 @@ bool avic_hardware_setup(void)
>  		return false;
>  	}
>  
> -	if (boot_cpu_has(X86_FEATURE_AVIC)) {
> -		pr_info("AVIC enabled\n");
> -	} else if (force_avic) {
> -		/*
> -		 * Some older systems does not advertise AVIC support.
> -		 * See Revision Guide for specific AMD processor for more detail.
> -		 */
> -		pr_warn("AVIC is not supported in CPUID but force enabled");
> -		pr_warn("Your system might crash and burn");
> -	}
> +	pr_info("AVIC enabled%s\n", cpu_feature_enabled(X86_FEATURE_AVIC) ? "" :
> +				    " (forced, your system may crash and burn)");

Except this bundles the scary forced message into pr_info, which isn't desirable
since KVM really should "yell" about AVIC being force enabled.  I 100% agree that
not printing "AVIC enabled" is mean, but I think we should do the super simple
thing and just always print exactly that.

>  
>  	/* AVIC is a prerequisite for x2AVIC. */
>  	x2avic_enabled = boot_cpu_has(X86_FEATURE_X2AVIC);
> -- 
> 2.50.1
>