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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 /arch/s390/kernel/early.c
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>
Diffstat (limited to 'arch/s390/kernel/early.c')
-rw-r--r--arch/s390/kernel/early.c22
1 files changed, 13 insertions, 9 deletions
diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index 2a2ca268b1dd..d61eb3334edf 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)