From 0592969e73ae50ce6852d1aff3d222a335289094 Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Fri, 17 Aug 2012 18:52:43 +0800 Subject: hv: fail the probing immediately when we are not in hyperv platform We wait for about 5 seconds for the success of the hyperv registration even if we were not in hyperv platform. This is suboptimal, so the patch check the cpuid in the beginning of hv_acpi_init() instead of in vmbus_bus_init() to fail the probing immediately. 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, 25 insertions(+) (limited to 'drivers/hv/vmbus_drv.c') diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index b76e8b321266..f40dd57bbec1 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -719,10 +719,35 @@ 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()) + return -ENODEV; + init_completion(&probe_event); /* -- cgit v1.2.3