KVM: x86: Consolidate SEV-ES MMIO emulation into a single public API

Dedup kvm_sev_es_mmio_{read,write}() into a single API, as the "cost" of
plumbing in a boolean is largely negligible since KVM pulls out a boolean
for ops->write anyways, and consolidating the APIs will allow for
additional cleanups.

No functional change intended.

Tested-by: Tom Lendacky <thomas.lendacky@gmail.com>
Tested-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Link: https://patch.msgid.link/20260225012049.920665-10-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

3 files changed, 17 insertions, 38 deletions

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 3f9c1aa39a0a..f3478fb9461d 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -4434,25 +4434,17 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
 
 	switch (control->exit_code) {
 	case SVM_VMGEXIT_MMIO_READ:
-		ret = setup_vmgexit_scratch(svm, true, control->exit_info_2);
-		if (ret)
-			break;
+	case SVM_VMGEXIT_MMIO_WRITE: {
+		bool is_write = control->exit_code == SVM_VMGEXIT_MMIO_WRITE;
 
-		ret = kvm_sev_es_mmio_read(vcpu,
-					   control->exit_info_1,
-					   control->exit_info_2,
-					   svm->sev_es.ghcb_sa);
-		break;
-	case SVM_VMGEXIT_MMIO_WRITE:
-		ret = setup_vmgexit_scratch(svm, false, control->exit_info_2);
+		ret = setup_vmgexit_scratch(svm, !is_write, control->exit_info_2);
 		if (ret)
 			break;
 
-		ret = kvm_sev_es_mmio_write(vcpu,
-					    control->exit_info_1,
-					    control->exit_info_2,
-					    svm->sev_es.ghcb_sa);
+		ret = kvm_sev_es_mmio(vcpu, is_write, control->exit_info_1,
+				      control->exit_info_2, svm->sev_es.ghcb_sa);
 		break;
+	}
 	case SVM_VMGEXIT_NMI_COMPLETE:
 		++vcpu->stat.nmi_window_exits;
 		svm->nmi_masked = false;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 81e683914072..6ecc3cf972ae 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -14292,9 +14292,8 @@ static int complete_sev_es_emulated_mmio(struct kvm_vcpu *vcpu)
 	return 0;
 }
 
-static int kvm_sev_es_do_mmio(struct kvm_vcpu *vcpu, gpa_t gpa,
-			      unsigned int bytes, void *data,
-			      const struct read_write_emulator_ops *ops)
+int kvm_sev_es_mmio(struct kvm_vcpu *vcpu, bool is_write, gpa_t gpa,
+		    unsigned int bytes, void *data)
 {
 	struct kvm_mmio_fragment *frag;
 	int handled;
@@ -14302,7 +14301,10 @@ static int kvm_sev_es_do_mmio(struct kvm_vcpu *vcpu, gpa_t gpa,
 	if (!data || WARN_ON_ONCE(object_is_on_stack(data)))
 		return -EINVAL;
 
-	handled = ops->read_write_mmio(vcpu, gpa, bytes, data);
+	if (is_write)
+		handled = vcpu_mmio_write(vcpu, gpa, bytes, data);
+	else
+		handled = vcpu_mmio_read(vcpu, gpa, bytes, data);
 	if (handled == bytes)
 		return 1;
 
@@ -14325,8 +14327,8 @@ static int kvm_sev_es_do_mmio(struct kvm_vcpu *vcpu, gpa_t gpa,
 
 	vcpu->run->mmio.phys_addr = gpa;
 	vcpu->run->mmio.len = min(8u, frag->len);
-	vcpu->run->mmio.is_write = ops->write;
-	if (ops->write)
+	vcpu->run->mmio.is_write = is_write;
+	if (is_write)
 		memcpy(vcpu->run->mmio.data, frag->data, min(8u, frag->len));
 	vcpu->run->exit_reason = KVM_EXIT_MMIO;
 
@@ -14334,20 +14336,7 @@ static int kvm_sev_es_do_mmio(struct kvm_vcpu *vcpu, gpa_t gpa,
 
 	return 0;
 }
-
-int kvm_sev_es_mmio_write(struct kvm_vcpu *vcpu, gpa_t gpa, unsigned int bytes,
-			  void *data)
-{
-	return kvm_sev_es_do_mmio(vcpu, gpa, bytes, data, &write_emultor);
-}
-EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_sev_es_mmio_write);
-
-int kvm_sev_es_mmio_read(struct kvm_vcpu *vcpu, gpa_t gpa, unsigned int bytes,
-			 void *data)
-{
-	return kvm_sev_es_do_mmio(vcpu, gpa, bytes, data, &read_emultor);
-}
-EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_sev_es_mmio_read);
+EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_sev_es_mmio);
 
 static void advance_sev_es_emulated_pio(struct kvm_vcpu *vcpu, unsigned count, int size)
 {
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 94d4f07aaaa0..1d0f0edd31b3 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -712,10 +712,8 @@ static inline bool __kvm_is_valid_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
 	__reserved_bits;                                \
 })
 
-int kvm_sev_es_mmio_write(struct kvm_vcpu *vcpu, gpa_t src, unsigned int bytes,
-			  void *dst);
-int kvm_sev_es_mmio_read(struct kvm_vcpu *vcpu, gpa_t src, unsigned int bytes,
-			 void *dst);
+int kvm_sev_es_mmio(struct kvm_vcpu *vcpu, bool is_write, gpa_t gpa,
+		    unsigned int bytes, void *data);
 int kvm_sev_es_string_io(struct kvm_vcpu *vcpu, unsigned int size,
 			 unsigned int port, void *data,  unsigned int count,
 			 int in);