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-rw-r--r--arch/s390/Kconfig7
-rw-r--r--arch/s390/kernel/early.c4
-rw-r--r--arch/s390/kernel/setup.c10
-rw-r--r--include/asm-s390/setup.h1
4 files changed, 19 insertions, 3 deletions
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 9a742ce9cc92..8f5f02160ffc 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -520,6 +520,13 @@ config ZFCPDUMP
 	  Select this option if you want to build an zfcpdump enabled kernel.
 	  Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this.
 
+config S390_GUEST
+bool "s390 guest support (EXPERIMENTAL)"
+	depends on 64BIT && EXPERIMENTAL
+	select VIRTIO
+	select VIRTIO_RING
+	help
+	  Select this option if you want to run the kernel under s390 linux
 endmenu
 
 source "net/Kconfig"
diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index 540a67f979b6..68ec4083bf73 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -144,6 +144,10 @@ static noinline __init void detect_machine_type(void)
 	/* Running on a P/390 ? */
 	if (cpuinfo->cpu_id.machine == 0x7490)
 		machine_flags |= 4;
+
+	/* Running under KVM ? */
+	if (cpuinfo->cpu_id.version == 0xfe)
+		machine_flags |= 64;
 }
 
 #ifdef CONFIG_64BIT
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 2f35133ebc18..a9d18aafa5f4 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -801,9 +801,13 @@ setup_arch(char **cmdline_p)
 	       "This machine has an IEEE fpu\n" :
 	       "This machine has no IEEE fpu\n");
 #else /* CONFIG_64BIT */
-	printk((MACHINE_IS_VM) ?
-	       "We are running under VM (64 bit mode)\n" :
-	       "We are running native (64 bit mode)\n");
+	if (MACHINE_IS_VM)
+		printk("We are running under VM (64 bit mode)\n");
+	else if (MACHINE_IS_KVM) {
+		printk("We are running under KVM (64 bit mode)\n");
+		add_preferred_console("ttyS", 1, NULL);
+	} else
+		printk("We are running native (64 bit mode)\n");
 #endif /* CONFIG_64BIT */
 
 	/* Save unparsed command line copy for /proc/cmdline */
diff --git a/include/asm-s390/setup.h b/include/asm-s390/setup.h
index a76a6b8fd887..aaf4b518b940 100644
--- a/include/asm-s390/setup.h
+++ b/include/asm-s390/setup.h
@@ -62,6 +62,7 @@ extern unsigned long machine_flags;
 #define MACHINE_IS_VM		(machine_flags & 1)
 #define MACHINE_IS_P390		(machine_flags & 4)
 #define MACHINE_HAS_MVPG	(machine_flags & 16)
+#define MACHINE_IS_KVM		(machine_flags & 64)
 #define MACHINE_HAS_IDTE	(machine_flags & 128)
 #define MACHINE_HAS_DIAG9C	(machine_flags & 256)