[v7,7/8] KVM: SVM: Add support to initialize SEV/SNP functionality in KVM

Commit Message

Ashish Kalra March 24, 2025, 9:15 p.m. UTC

From: Ashish Kalra <[e-mail]>

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.

Continue to support SEV deferred initialization as the user may have the
file containing SEV persistent data for SEV INIT_EX available only later
after module load/init.

Suggested-by: Sean Christopherson <[e-mail]>
Reviewed-by: Tom Lendacky <[e-mail]>
Signed-off-by: Ashish Kalra <[e-mail]>
---
 arch/x86/kvm/svm/sev.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

Patch

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 0bc708ee2788..7be4e1647903 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 +3060,15 @@  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;
+
+	/*
+	 * Do both SNP and SEV initialization at KVM module load.
+	 */
+	init_args.probe = true;
+	sev_platform_init(&init_args);
 }
 
 void sev_hardware_unsetup(void)
@@ -3074,6 +3084,8 @@  void sev_hardware_unsetup(void)
 
 	misc_cg_set_capacity(MISC_CG_RES_SEV, 0);
 	misc_cg_set_capacity(MISC_CG_RES_SEV_ES, 0);
+
+	sev_platform_shutdown();
 }
 
 int sev_cpu_init(struct svm_cpu_data *sd)