[PATCH v4 08/11] KVM: arm64: Move the host hypercall interface to its own header

[Fuad Tabba <fuad.tabba@linux.dev>]

Move the kvm_call_hyp() dispatch macros and pkvm_handle_t out of
kvm_host.h into a new kvm_hcall.h, giving the host<->hyp hypercall
interface a single home that subsequent patches build on to restore
type-checking across the boundary. The only adjustment to the moved
code is the checkpatch-mandated space in "while (0)".

No functional change intended.

Reviewed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
---
 arch/arm64/include/asm/kvm_hcall.h | 68 ++++++++++++++++++++++++++++++
 arch/arm64/include/asm/kvm_host.h  | 48 +--------------------
 2 files changed, 69 insertions(+), 47 deletions(-)
 create mode 100644 arch/arm64/include/asm/kvm_hcall.h

diff --git a/arch/arm64/include/asm/kvm_hcall.h b/arch/arm64/include/asm/kvm_hcall.h
new file mode 100644
index 0000000000000..d925b2c28a3d8
--- /dev/null
+++ b/arch/arm64/include/asm/kvm_hcall.h
@@ -0,0 +1,68 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * The host<->hyp hypercall interface.
+ *
+ * Copyright (C) 2026 Google LLC
+ * Author: Fuad Tabba <fuad.tabba@linux.dev>
+ */
+
+#ifndef __ARM64_KVM_HCALL_H__
+#define __ARM64_KVM_HCALL_H__
+
+#include <linux/arm-smccc.h>
+#include <linux/bug.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+
+#include <asm/barrier.h>
+#include <asm/kvm_asm.h>
+#include <asm/virt.h>
+
+typedef u16 pkvm_handle_t;
+
+#ifndef __KVM_NVHE_HYPERVISOR__
+#define kvm_call_hyp_nvhe(f, ...)					\
+	({								\
+		struct arm_smccc_res res;				\
+									\
+		arm_smccc_1_1_hvc(KVM_HOST_SMCCC_FUNC(f),		\
+				  ##__VA_ARGS__, &res);			\
+		if (WARN_ON(res.a0 != SMCCC_RET_SUCCESS))		\
+			res.a1 = -EOPNOTSUPP;				\
+									\
+		res.a1;							\
+	})
+
+/*
+ * The isb() below is there to guarantee the same behaviour on VHE as on !VHE,
+ * where the eret to EL1 acts as a context synchronization event.
+ */
+#define kvm_call_hyp(f, ...)						\
+	do {								\
+		if (has_vhe()) {					\
+			f(__VA_ARGS__);					\
+			isb();						\
+		} else {						\
+			kvm_call_hyp_nvhe(f, ##__VA_ARGS__);		\
+		}							\
+	} while (0)
+
+#define kvm_call_hyp_ret(f, ...)					\
+	({								\
+		typeof(f(__VA_ARGS__)) ret;				\
+									\
+		if (has_vhe()) {					\
+			ret = f(__VA_ARGS__);				\
+		} else {						\
+			ret = kvm_call_hyp_nvhe(f, ##__VA_ARGS__);	\
+		}							\
+									\
+		ret;							\
+	})
+#else /* __KVM_NVHE_HYPERVISOR__ */
+#define kvm_call_hyp(f, ...) f(__VA_ARGS__)
+#define kvm_call_hyp_ret(f, ...) f(__VA_ARGS__)
+#define kvm_call_hyp_nvhe(f, ...) f(__VA_ARGS__)
+#endif /* __KVM_NVHE_HYPERVISOR__ */
+
+#endif /* __ARM64_KVM_HCALL_H__ */
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 27fe0cd5b2d7a..fc1a82777ed48 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -27,6 +27,7 @@
 #include <asm/fpsimd.h>
 #include <asm/kvm.h>
 #include <asm/kvm_asm.h>
+#include <asm/kvm_hcall.h>
 #include <asm/vncr_mapping.h>
 
 #define __KVM_HAVE_ARCH_INTC_INITIALIZED
@@ -251,8 +252,6 @@ struct kvm_smccc_features {
 	unsigned long vendor_hyp_bmap_2; /* Function numbers 64-127 */
 };
 
-typedef u16 pkvm_handle_t;
-
 struct kvm_protected_vm {
 	pkvm_handle_t handle;
 	struct kvm_hyp_memcache teardown_mc;
@@ -1258,51 +1257,6 @@ void kvm_arm_resume_guest(struct kvm *kvm);
 
 #define vcpu_has_run_once(vcpu)	(!!READ_ONCE((vcpu)->pid))
 
-#ifndef __KVM_NVHE_HYPERVISOR__
-#define kvm_call_hyp_nvhe(f, ...)					\
-	({								\
-		struct arm_smccc_res res;				\
-									\
-		arm_smccc_1_1_hvc(KVM_HOST_SMCCC_FUNC(f),		\
-				  ##__VA_ARGS__, &res);			\
-		if (WARN_ON(res.a0 != SMCCC_RET_SUCCESS))		\
-			res.a1 = -EOPNOTSUPP;				\
-									\
-		res.a1;							\
-	})
-
-/*
- * The isb() below is there to guarantee the same behaviour on VHE as on !VHE,
- * where the eret to EL1 acts as a context synchronization event.
- */
-#define kvm_call_hyp(f, ...)						\
-	do {								\
-		if (has_vhe()) {					\
-			f(__VA_ARGS__);					\
-			isb();						\
-		} else {						\
-			kvm_call_hyp_nvhe(f, ##__VA_ARGS__);		\
-		}							\
-	} while(0)
-
-#define kvm_call_hyp_ret(f, ...)					\
-	({								\
-		typeof(f(__VA_ARGS__)) ret;				\
-									\
-		if (has_vhe()) {					\
-			ret = f(__VA_ARGS__);				\
-		} else {						\
-			ret = kvm_call_hyp_nvhe(f, ##__VA_ARGS__);	\
-		}							\
-									\
-		ret;							\
-	})
-#else /* __KVM_NVHE_HYPERVISOR__ */
-#define kvm_call_hyp(f, ...) f(__VA_ARGS__)
-#define kvm_call_hyp_ret(f, ...) f(__VA_ARGS__)
-#define kvm_call_hyp_nvhe(f, ...) f(__VA_ARGS__)
-#endif /* __KVM_NVHE_HYPERVISOR__ */
-
 int handle_exit(struct kvm_vcpu *vcpu, int exception_index);
 void handle_exit_early(struct kvm_vcpu *vcpu, int exception_index);
 
-- 
2.39.5