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authorJason Wang <jasowang@redhat.com>2012-08-31 09:32:44 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-09-05 02:55:34 +0400
commit1f94ea8181a9305a5d5cf635a6a4e9ac8ee3d2c3 (patch)
tree995ce59ace664ddcbab58a4042dac1b8e8e346f4 /drivers/hv
parent82aceae4f0d42f03d9ad7d1e90389e731153898f (diff)
downloadlinux-1f94ea8181a9305a5d5cf635a6a4e9ac8ee3d2c3.tar.xz
hv: vmbus_drv: detect hyperv through x86_hyper
There are two reasons we need to use x86_hyper instead of query_hypervisor_presence(): - Not only hyperv but also other hypervisors such as kvm would set X86_FEATURE_HYTPERVISOR, so query_hypervisor_presence() will return true even in kvm. This may cause extra delay of 5 seconds before failing the probing in kvm guest. - The hypervisor has been detected in init_hypervisor(), so no need to do the work again. Signed-off-by: Jason Wang <jasowang@redhat.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Acked-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/hv')
-rw-r--r--drivers/hv/vmbus_drv.c25
1 files changed, 2 insertions, 23 deletions
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index f40dd57bbec1..8e1a9ec53003 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -34,6 +34,7 @@
#include <linux/completion.h>
#include <linux/hyperv.h>
#include <asm/hyperv.h>
+#include <asm/hypervisor.h>
#include "hyperv_vmbus.h"
@@ -719,33 +720,11 @@ static struct acpi_driver vmbus_acpi_driver = {
},
};
-/*
- * query_hypervisor_presence
- * - Query the cpuid for presence of windows hypervisor
- */
-static int query_hypervisor_presence(void)
-{
- unsigned int eax;
- unsigned int ebx;
- unsigned int ecx;
- unsigned int edx;
- unsigned int op;
-
- eax = 0;
- ebx = 0;
- ecx = 0;
- edx = 0;
- op = HVCPUID_VERSION_FEATURES;
- cpuid(op, &eax, &ebx, &ecx, &edx);
-
- return ecx & HV_PRESENT_BIT;
-}
-
static int __init hv_acpi_init(void)
{
int ret, t;
- if (!query_hypervisor_presence())
+ if (x86_hyper != &x86_hyper_ms_hyperv)
return -ENODEV;
init_completion(&probe_event);