linux-kernel - Re: [PATCH 3/4] KVM: SVM: Ensure PSP module initialized before built-in KVM module

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Message-ID: <6a18b6bc-d350-0aca-9a68-d819552ef91f@amd.com>
Date: Wed, 22 Jan 2025 09:58:14 -0600
From: Tom Lendacky <thomas.lendacky@....com>
To: Ashish Kalra <Ashish.Kalra@....com>, seanjc@...gle.com,
 pbonzini@...hat.com, tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
 dave.hansen@...ux.intel.com, x86@...nel.org, hpa@...or.com,
 john.allen@....com, herbert@...dor.apana.org.au, davem@...emloft.net,
 joro@...tes.org, suravee.suthikulpanit@....com, will@...nel.org,
 robin.murphy@....com
Cc: michael.roth@....com, dionnaglaze@...gle.com, vasant.hegde@....com,
 kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-crypto@...r.kernel.org, linux-coco@...ts.linux.dev,
 iommu@...ts.linux.dev
Subject: Re: [PATCH 3/4] KVM: SVM: Ensure PSP module initialized before
 built-in KVM module

On 1/21/25 19:00, Ashish Kalra wrote:
> From: Sean Christopherson <seanjc@...gle.com>
> 
> The kernel's initcall infrastructure lacks the ability to express
> dependencies between initcalls, where as the modules infrastructure
> automatically handles dependencies via symbol loading. Ensure the
> PSP SEV driver is initialized before proceeding in sev_hardware_setup()
> if KVM is built-in as the dependency isn't handled by the initcall
> infrastructure.
> 
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>

Requires your Signed-off-by:

> ---
>  arch/x86/kvm/svm/sev.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index 5a13c5224942..de404d493759 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c
> @@ -2972,6 +2972,16 @@ void __init sev_hardware_setup(void)
>  	    WARN_ON_ONCE(!boot_cpu_has(X86_FEATURE_FLUSHBYASID)))
>  		goto out;
>  
> +	/*
> +	 * The kernel's initcall infrastructure lacks the ability to express
> +	 * dependencies between initcalls, where as the modules infrastructure

s/where as/whereas/

Thanks,
Tom

> +	 * automatically handles dependencies via symbol loading.  Ensure the
> +	 * PSP SEV driver is initialized before proceeding if KVM is built-in,
> +	 * as the dependency isn't handled by the initcall infrastructure.
> +	 */
> +	if (IS_BUILTIN(CONFIG_KVM_AMD) && sev_module_init())
> +		goto out;
> +
>  	/* Retrieve SEV CPUID information */
>  	cpuid(0x8000001f, &eax, &ebx, &ecx, &edx);
>