linux-kernel - [PATCH v5 6/7] KVM: SVM: Add support to initialize SEV/SNP functionality in KVM

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Message-ID: <27a491ee16015824b416e72921b02a02c27433f7.1740512583.git.ashish.kalra@amd.com>
Date: Tue, 25 Feb 2025 21:01:33 +0000
From: Ashish Kalra <Ashish.Kalra@....com>
To: <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>, <thomas.lendacky@....com>,
	<john.allen@....com>, <herbert@...dor.apana.org.au>
CC: <michael.roth@....com>, <dionnaglaze@...gle.com>, <nikunj@....com>,
	<ardb@...nel.org>, <kevinloughlin@...gle.com>, <Neeraj.Upadhyay@....com>,
	<aik@....com>, <kvm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-crypto@...r.kernel.org>, <linux-coco@...ts.linux.dev>
Subject: [PATCH v5 6/7] KVM: SVM: Add support to initialize SEV/SNP functionality in KVM

From: Ashish Kalra <ashish.kalra@....com>

Move platform initialization of SEV/SNP from CCP driver probe time to
KVM module load time so that KVM can do SEV/SNP platform initialization
explicitly if it actually wants to use SEV/SNP functionality.

Add support for KVM to explicitly call into the CCP driver at load time
to initialize SEV/SNP. If required, this behavior can be altered with KVM
module parameters to not do SEV/SNP platform initialization at module load
time. Additionally, a corresponding SEV/SNP platform shutdown is invoked
during KVM module unload time.

Suggested-by: Sean Christopherson <seanjc@...gle.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@....com>
Signed-off-by: Ashish Kalra <ashish.kalra@....com>
---
 arch/x86/kvm/svm/sev.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 74525651770a..0bc6c0486071 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -2933,6 +2933,7 @@ void __init sev_set_cpu_caps(void)
 void __init sev_hardware_setup(void)
 {
 	unsigned int eax, ebx, ecx, edx, sev_asid_count, sev_es_asid_count;
+	struct sev_platform_init_args init_args = {0};
 	bool sev_snp_supported = false;
 	bool sev_es_supported = false;
 	bool sev_supported = false;
@@ -3059,6 +3060,17 @@ void __init sev_hardware_setup(void)
 	sev_supported_vmsa_features = 0;
 	if (sev_es_debug_swap_enabled)
 		sev_supported_vmsa_features |= SVM_SEV_FEAT_DEBUG_SWAP;
+
+	if (!sev_enabled)
+		return;
+
+	/*
+	 * Always perform SEV initialization at setup time to avoid
+	 * complications when performing SEV initialization later
+	 * (such as suspending active guests, etc.).
+	 */
+	init_args.probe = true;
+	sev_platform_init(&init_args);
 }
 
 void sev_hardware_unsetup(void)
@@ -3074,6 +3086,9 @@ void sev_hardware_unsetup(void)
 
 	misc_cg_set_capacity(MISC_CG_RES_SEV, 0);
 	misc_cg_set_capacity(MISC_CG_RES_SEV_ES, 0);
+
+	/* Do SEV and SNP Shutdown */
+	sev_platform_shutdown();
 }
 
 int sev_cpu_init(struct svm_cpu_data *sd)
-- 
2.34.1