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Commit 1f94ea81 authored by Jason Wang's avatar Jason Wang Committed by Greg Kroah-Hartman
Browse files

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: default avatarJason Wang <jasowang@redhat.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Acked-by: default avatarK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 82aceae4

drivers/hv/vmbus_drv.c

+2 −23
Original line number Diff line number Diff line
@@ -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);