accel/nvmm: Expose nvmm_enabled() to common code

Currently nvmm_enabled() is restricted to target-specific code.
By defining CONFIG_NVMM_IS_POSSIBLE we allow its use anywhere.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Message-Id: <20250703173248.44995-25-philmd@linaro.org>

MAINTAINERS

@@ -586,6 +586,7 @@ NetBSD Virtual Machine Monitor (NVMM) CPU support
 M: Reinoud Zandijk <reinoud@netbsd.org>
 S: Maintained
 F: include/system/nvmm.h
+F: accel/stubs/nvmm-stub.c
 F: target/i386/nvmm/
 
 Hosts

accel/stubs/meson.build

@@ -3,5 +3,6 @@ system_stubs_ss.add(when: 'CONFIG_XEN', if_false: files('xen-stub.c'))
 system_stubs_ss.add(when: 'CONFIG_KVM', if_false: files('kvm-stub.c'))
 system_stubs_ss.add(when: 'CONFIG_TCG', if_false: files('tcg-stub.c'))
 system_stubs_ss.add(when: 'CONFIG_HVF', if_false: files('hvf-stub.c'))
+system_stubs_ss.add(when: 'CONFIG_NVMM', if_false: files('nvmm-stub.c'))
 
 specific_ss.add_all(when: ['CONFIG_SYSTEM_ONLY'], if_true: system_stubs_ss)

accel/stubs/nvmm-stub.c

@@ -0,0 +1,12 @@
+/*
+ * NVMM stubs for QEMU
+ *
+ *  Copyright (c) Linaro
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "system/nvmm.h"
+
+bool nvmm_allowed;

include/system/nvmm.h

@@ -13,17 +13,18 @@
 #define QEMU_NVMM_H
 
 #ifdef COMPILING_PER_TARGET
-
-#ifdef CONFIG_NVMM
-
-int nvmm_enabled(void);
-
-#else /* CONFIG_NVMM */
-
-#define nvmm_enabled() (0)
-
-#endif /* CONFIG_NVMM */
-
+# ifdef CONFIG_NVMM
+#  define CONFIG_NVMM_IS_POSSIBLE
+# endif /* !CONFIG_NVMM */
+#else
+# define CONFIG_NVMM_IS_POSSIBLE
 #endif /* COMPILING_PER_TARGET */
 
+#ifdef CONFIG_NVMM_IS_POSSIBLE
+extern bool nvmm_allowed;
+#define nvmm_enabled() (nvmm_allowed)
+#else /* !CONFIG_NVMM_IS_POSSIBLE */
+#define nvmm_enabled() 0
+#endif /* !CONFIG_NVMM_IS_POSSIBLE */
+
 #endif /* QEMU_NVMM_H */

target/i386/nvmm/nvmm-all.c

@@ -46,7 +46,7 @@ struct qemu_machine {
 
 /* -------------------------------------------------------------------------- */
 
-static bool nvmm_allowed;
+bool nvmm_allowed;
 static struct qemu_machine qemu_mach;
 
 static struct nvmm_machine *
@@ -1192,12 +1192,6 @@ nvmm_accel_init(MachineState *ms)
     return 0;
 }
 
-int
-nvmm_enabled(void)
-{
-    return nvmm_allowed;
-}
-
 static void
 nvmm_accel_class_init(ObjectClass *oc, const void *data)
 {