diff options
Diffstat (limited to 'drivers/hv/vmbus_drv.c')
| -rw-r--r-- | drivers/hv/vmbus_drv.c | 25 |
1 files changed, 25 insertions, 0 deletions
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); /* |