From fa5877439d5a062d91c3abd5a690483bbdb4268e Mon Sep 17 00:00:00 2001 From: Carsten Otte Date: Tue, 25 Mar 2008 18:47:44 +0100 Subject: [PATCH] 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 Acked-by: Martin Schwidefsky Signed-off-by: Carsten Otte Signed-off-by: Avi Kivity --- arch/s390/Kconfig | 7 +++++++ arch/s390/kernel/early.c | 4 ++++ arch/s390/kernel/setup.c | 10 +++++++--- include/asm-s390/setup.h | 1 + 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 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) -- 2.39.5