[PATCH v6 8/8] KVM: SVM: Delay legacy platform initialization on SNP

[Dionna Glaze <dionnaglaze@google.com>]

When no SEV or SEV-ES guests are active, then the firmware can be
updated while (SEV-SNP) VM guests are active.

CC: Sean Christopherson <seanjc@google.com>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Ingo Molnar <mingo@redhat.com>
CC: Borislav Petkov <bp@alien8.de>
CC: Dave Hansen <dave.hansen@linux.intel.com>
CC: Ashish Kalra <ashish.kalra@amd.com>
CC: Tom Lendacky <thomas.lendacky@amd.com>
CC: John Allen <john.allen@amd.com>
CC: Herbert Xu <herbert@gondor.apana.org.au>
CC: "David S. Miller" <davem@davemloft.net>
CC: Michael Roth <michael.roth@amd.com>
CC: Luis Chamberlain <mcgrof@kernel.org>
CC: Russ Weight <russ.weight@linux.dev>
CC: Danilo Krummrich <dakr@redhat.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: "Rafael J. Wysocki" <rafael@kernel.org>
CC: Tianfei zhang <tianfei.zhang@intel.com>
CC: Alexey Kardashevskiy <aik@amd.com>

Co-developed-by: Ashish Kalra <ashish.kalra@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Reviewed-by: Ashish Kalra <ashish.kalra@amd.com>
Signed-off-by: Dionna Glaze <dionnaglaze@google.com>
---
 arch/x86/kvm/svm/sev.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 5e6d1f1c14dfd..507ed87749f55 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -444,7 +444,11 @@ static int __sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp,
 	if (ret)
 		goto e_no_asid;
 
-	init_args.probe = false;
+	/*
+	 * Setting probe will skip SEV/SEV-ES platform initialization for an SEV-SNP guest in order
+	 * for SNP firmware hotloading to be available when only SEV-SNP VMs are running.
+	 */
+	init_args.probe = vm_type != KVM_X86_SEV_VM && vm_type != KVM_X86_SEV_ES_VM;
 	ret = sev_platform_init(&init_args);
 	if (ret)
 		goto e_free;
-- 
2.47.0.277.g8800431eea-goog