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.
Cc: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx>
Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
drivers/hv/vmbus_drv.c | 25 ++-----------------------
1 files changed, 2 insertions(+), 23 deletions(-)
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index f40dd57..8e1a9ec 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);
--
1.7.1
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