[PATCH 6.12.y] KVM: SEV: Wire up kvm_x86_ops.gmem_xxx() if and only if CONFIG_KVM_AMD_SEV=y

[Sasha Levin <sashal@kernel.org>]

From: Sean Christopherson <seanjc@google.com>

[ Upstream commit 01a96ff30dde5127c37497f1e098e639e7ae152f ]

Wire up the SEV-SNP guest_memfd kvm_x86_ops hooks if and only if SEV is
actually enabled, and drop the now-unnecessary stubs.  Leaving the hooks
NULL allows the static call infrastructure to elide the CALL+RET, and more
importantly, referencing the hooks if and only if SEV support is enabled
will allow conditionally definining the hooks using their corresponding
HAVE_KVM_ARCH_GMEM_XXX Kconfig.

No functional change intended.

Cc: stable@vger.kernel.org # 6.12.x
Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Link: https://patch.msgid.link/20260709204948.1988414-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
[ adapted gmem_max_mapping_level hook to the older private_max_mapping_level API ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/svm/svm.c |  8 ++++----
 arch/x86/kvm/svm/svm.h | 10 ----------
 2 files changed, 4 insertions(+), 14 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 44819d9470dcf..13fc10a12cb51 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -5303,6 +5303,10 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
 
 	.vm_copy_enc_context_from = sev_vm_copy_enc_context_from,
 	.vm_move_enc_context_from = sev_vm_move_enc_context_from,
+
+	.gmem_prepare = sev_gmem_prepare,
+	.gmem_invalidate = sev_gmem_invalidate,
+	.private_max_mapping_level = sev_private_max_mapping_level,
 #endif
 	.check_emulate_instruction = svm_check_emulate_instruction,
 
@@ -5314,10 +5318,6 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.vcpu_deliver_sipi_vector = svm_vcpu_deliver_sipi_vector,
 	.vcpu_get_apicv_inhibit_reasons = avic_vcpu_get_apicv_inhibit_reasons,
 	.alloc_apic_backing_page = svm_alloc_apic_backing_page,
-
-	.gmem_prepare = sev_gmem_prepare,
-	.gmem_invalidate = sev_gmem_invalidate,
-	.private_max_mapping_level = sev_private_max_mapping_level,
 };
 
 /*
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index c34cd7f1408fc..387fc4ffcdeac 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -791,16 +791,6 @@ static inline int sev_dev_get_attr(u32 group, u64 attr, u64 *val) { return -ENXI
 #define max_sev_asid 0
 static inline void sev_handle_rmp_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u64 error_code) {}
 static inline void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu) {}
-static inline int sev_gmem_prepare(struct kvm *kvm, kvm_pfn_t pfn, gfn_t gfn, int max_order)
-{
-	return 0;
-}
-static inline void sev_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end) {}
-static inline int sev_private_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn)
-{
-	return 0;
-}
-
 #endif
 
 /* vmenter.S */
-- 
2.53.0