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s390: KVM guest: detect when running on kvm

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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>
This commit is contained in:
Carsten Otte 2008-03-25 18:47:44 +01:00 committed by Avi Kivity
parent 85f8fffe3c
commit fa5877439d
4 changed files with 19 additions and 3 deletions
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7
arch/s390/Kconfig
View file

@ -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"

4
arch/s390/kernel/early.c
View file

@ -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

10
arch/s390/kernel/setup.c
View file

@ -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 */

1
include/asm-s390/setup.h
View file

@ -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)