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 = { | |||
719 | }, | 719 | }, |
720 | }; | 720 | }; |
721 | 721 | ||
722 | /* | ||
723 | * query_hypervisor_presence | ||
724 | * - Query the cpuid for presence of windows hypervisor | ||
725 | */ | ||
726 | static int query_hypervisor_presence(void) | ||
727 | { | ||
728 | unsigned int eax; | ||
729 | unsigned int ebx; | ||
730 | unsigned int ecx; | ||
731 | unsigned int edx; | ||
732 | unsigned int op; | ||
733 | |||
734 | eax = 0; | ||
735 | ebx = 0; | ||
736 | ecx = 0; | ||
737 | edx = 0; | ||
738 | op = HVCPUID_VERSION_FEATURES; | ||
739 | cpuid(op, &eax, &ebx, &ecx, &edx); | ||
740 | |||
741 | return ecx & HV_PRESENT_BIT; | ||
742 | } | ||
743 | |||
722 | static int __init hv_acpi_init(void) | 744 | static int __init hv_acpi_init(void) |
723 | { | 745 | { |
724 | int ret, t; | 746 | int ret, t; |
725 | 747 | ||
748 | if (!query_hypervisor_presence()) | ||
749 | return -ENODEV; | ||
750 | |||
726 | init_completion(&probe_event); | 751 | init_completion(&probe_event); |
727 | 752 | ||
728 | /* | 753 | /* |