cmake: only enable KVM if building on Linux

arch/x86_64/QEMU.cmake

@@ -8,6 +8,14 @@ find_program(LLDB lldb)
 find_program(GDB gdb)
 
 set(patched_kernel ${CMAKE_CURRENT_BINARY_DIR}/kernel/${kernel_name}.elf32)
+set(generic_flags -m 1G)
+
+if (${CMAKE_HOST_SYSTEM_NAME} STREQUAL "Linux")
+	message(STATUS "QEMU: Enabling KVM acceleration")
+	set(generic_flags ${generic_flags} -enable-kvm)
+else ()
+	message(STATUS "QEMU: Host system is not Linux. KVM acceleration unavailable")
+endif ()
 
 add_custom_command(OUTPUT ${patched_kernel}
 	DEPENDS ${kernel_name}
@@ -25,7 +33,8 @@ add_custom_target(run-kernel
 		${QEMU}
 		-kernel ${patched_kernel}
 		-initrd ${sys_dir}/${bsp_name}
-		-m 1G -serial stdio -enable-kvm
+		${generic_flags}
+		-serial stdio
 		--append kernel.early-console=ttyS0
 	USES_TERMINAL
 	DEPENDS ${patched_kernel} bsp)
@@ -35,7 +44,8 @@ add_custom_target(run-kernel-monitor
 		${QEMU}
 		-kernel $<TARGET_FILE:${kernel_name}>
 		-initrd ${sys_dir}/${bsp_name}
-		-m 1G -monitor stdio
+		${generic_flags}
+		-monitor stdio
 	USES_TERMINAL
 	DEPENDS ${kernel_name} bsp)
 
@@ -45,7 +55,7 @@ if (image_cdrom)
 		COMMAND
 			${QEMU}
 			-cdrom ${image_cdrom}
-			-m 1G
+			${generic_flags}
 			-serial stdio
 		USES_TERMINAL
 		DEPENDS ${image_cdrom})
@@ -58,8 +68,8 @@ if (LLDB)
 			${QEMU}
 				-kernel $<TARGET_FILE:${kernel_name}>
 				-initrd ${sys_dir}/${bsp_name}
-				-enable-kvm
-				-m 1G -s -S &
+				${generic_flags}
+				-s -S &
 			${LLDB}
 				-o "file ${CMAKE_BINARY_DIR}/kernel/${kernel_name}.debug"
 				-o "gdb-remote localhost:1234"
@@ -72,7 +82,8 @@ if (LLDB)
 			COMMAND
 				${QEMU}
 				-cdrom ${image_cdrom}
-				-m 1G -s -S &
+				${generic_flags}
+				-s -S &
 			${LLDB}
 				-o "file ${CMAKE_BINARY_DIR}/kernel/${kernel_name}.debug"
 				-o "target remote localhost:1234"
@@ -86,7 +97,8 @@ elseif (GDB)
 			${QEMU}
 				-kernel $<TARGET_FILE:${kernel_name}>
 				-initrd ${sys_dir}/${bsp_name}
-				-m 1G -s -S &
+				${generic_flags}
+				-s -S &
 			${GDB}
 				-o "file ${CMAKE_BINARY_DIR}/kernel/${kernel_name}.debug"
 				-o "remote localhost:1234"
@@ -99,7 +111,8 @@ elseif (GDB)
 			COMMAND
 				${QEMU}
 				-cdrom ${image_cdrom}
-				-m 1G -s -S &
+				${generic_flags}
+				-s -S &
 			${GDB}  -tui
 				-s "${CMAKE_BINARY_DIR}/kernel/${kernel_name}.debug"
 				-ex "target remote localhost:1234"