s390: KVM guest: detect when running on kvm

This patch adds functionality to detect if the kernel runs under the KVM
hypervisor. A macro MACHINE_IS_KVM is exported for device drivers. This
allows drivers to skip device detection if the systems runs non-virtualized.
We also define a preferred console to avoid having the ttyS0, which is a line
mode only console.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 7 insertions, 0 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"