From 1f94ea8181a9305a5d5cf635a6a4e9ac8ee3d2c3 Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Fri, 31 Aug 2012 13:32:44 +0800 Subject: [PATCH] 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 Cc: Haiyang Zhang Acked-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman --- drivers/hv/vmbus_drv.c | 25 ++----------------------- 1 file changed, 2 insertions(+), 23 deletions(-) diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index f40dd57bbec..8e1a9ec5300 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -34,6 +34,7 @@ #include #include #include +#include #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); -- 2.20.1