[PATCH v4 6/7] KVM: SVM: Add support to initialize SEV/SNP functionality in KVM

[Ashish Kalra]

From: Ashish Kalra <ashish.kalra@xxxxxxx>

Move platform initialization of SEV/SNP from PSP 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 PSP driver at load time
to initialize SEV/SNP by default but this behavior can be altered with KVM
module parameters to not do SEV/SNP platform initialization at module load
time if required. Additionally SEV/SNP platform shutdown is invoked during
KVM module unload time.

Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Ashish Kalra <ashish.kalra@xxxxxxx>
---
 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..213d4c15a9da 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;
+
+	/*
+	 * NOTE: Always do SNP INIT regardless of sev_snp_supported
+	 * as SNP INIT has to be done to launch legacy SEV/SEV-ES
+	 * VMs in case SNP is enabled system-wide.
+	 */
+	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