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authorChristian Borntraeger <borntraeger@de.ibm.com>2009-03-26 15:23:58 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2009-03-26 15:24:09 +0100
commit92e6ecf392fac3082653ac9d84b1bdf53d0ea160 (patch)
treef5169e11ecce5d6ac13b2b2bb99088bdd9fe03e4
parent702d9e584feb028ed7e2a6d2b103b8ea57622ff2 (diff)
[S390] Fix hypervisor detection for KVM
Currently we use the cpuid (via STIDP instruction) to recognize LPAR, z/VM and KVM. The architecture states, that bit 0-7 of STIDP returns all zero, and if STIDP is executed in a virtual machine, the VM operating system will replace bits 0-7 with FF. KVM should not use FE to distinguish z/VM from KVM for interested guests. The proper way to detect the hypervisor is the STSI (Store System Information) instruction, which return information about the hypervisors via function code 3, selector1=2, selector2=2. This patch changes the detection routine of Linux to use STSI instead of STIDP. This detection is earlier than bootmem, we have to use a static buffer. Since STSI expects a 4kb block (4kb aligned) this patch also changes the init.data alignment for s390. As this section will be freed during boot, this should be no problem. Patch is tested with LPAR, z/VM, KVM on LPAR, and KVM under z/VM. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
-rw-r--r--arch/s390/include/asm/sysinfo.h1
-rw-r--r--arch/s390/kernel/early.c22
-rw-r--r--arch/s390/kernel/vmlinux.lds.S2
-rw-r--r--arch/s390/kvm/kvm-s390.c2
4 files changed, 17 insertions, 10 deletions
diff --git a/arch/s390/include/asm/sysinfo.h b/arch/s390/include/asm/sysinfo.h
index ad93212d9e1..9d70057d828 100644
--- a/arch/s390/include/asm/sysinfo.h
+++ b/arch/s390/include/asm/sysinfo.h
@@ -100,6 +100,7 @@ struct sysinfo_3_2_2 {
char reserved_1[24];
} vm[8];
+ char reserved_544[3552];
};
static inline int stsi(void *sysinfo, int fc, int sel1, int sel2)
diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index 2a2ca268b1d..d61eb3334ed 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -6,6 +6,7 @@
* Heiko Carstens <heiko.carstens@de.ibm.com>
*/
+#include <linux/compiler.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/string.h>
@@ -20,6 +21,7 @@
#include <asm/processor.h>
#include <asm/sections.h>
#include <asm/setup.h>
+#include <asm/sysinfo.h>
#include <asm/cpcmd.h>
#include <asm/sclp.h>
#include "entry.h"
@@ -173,19 +175,21 @@ static noinline __init void init_kernel_storage_key(void)
page_set_storage_key(init_pfn << PAGE_SHIFT, PAGE_DEFAULT_KEY);
}
+static __initdata struct sysinfo_3_2_2 vmms __aligned(PAGE_SIZE);
+
static noinline __init void detect_machine_type(void)
{
- struct cpuinfo_S390 *cpuinfo = &S390_lowcore.cpu_data;
-
- get_cpu_id(&S390_lowcore.cpu_data.cpu_id);
-
- /* Running under z/VM ? */
- if (cpuinfo->cpu_id.version == 0xff)
- machine_flags |= MACHINE_FLAG_VM;
+ /* No VM information? Looks like LPAR */
+ if (stsi(&vmms, 3, 2, 2) == -ENOSYS)
+ return;
+ if (!vmms.count)
+ return;
- /* Running under KVM ? */
- if (cpuinfo->cpu_id.version == 0xfe)
+ /* Running under KVM? If not we assume z/VM */
+ if (!memcmp(vmms.vm[0].cpi, "\xd2\xe5\xd4", 3))
machine_flags |= MACHINE_FLAG_KVM;
+ else
+ machine_flags |= MACHINE_FLAG_VM;
}
static __init void early_pgm_check_handler(void)
diff --git a/arch/s390/kernel/vmlinux.lds.S b/arch/s390/kernel/vmlinux.lds.S
index d796d05c9c0..7a2063eb88f 100644
--- a/arch/s390/kernel/vmlinux.lds.S
+++ b/arch/s390/kernel/vmlinux.lds.S
@@ -108,6 +108,8 @@ SECTIONS
EXIT_TEXT
}
+ /* early.c uses stsi, which requires page aligned data. */
+ . = ALIGN(PAGE_SIZE);
.init.data : {
INIT_DATA
}
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 0d33893e1e8..c55a4b9ffd8 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -286,7 +286,7 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
setup_timer(&vcpu->arch.ckc_timer, kvm_s390_idle_wakeup,
(unsigned long) vcpu);
get_cpu_id(&vcpu->arch.cpu_id);
- vcpu->arch.cpu_id.version = 0xfe;
+ vcpu->arch.cpu_id.version = 0xff;
return 0;
}