diff options
author | Jason Wang <jasowang@redhat.com> | 2012-08-31 13:32:44 +0800 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-09-04 15:55:34 -0700 |
commit | 1f94ea8181a9305a5d5cf635a6a4e9ac8ee3d2c3 (patch) | |
tree | 995ce59ace664ddcbab58a4042dac1b8e8e346f4 /drivers | |
parent | 82aceae4f0d42f03d9ad7d1e90389e731153898f (diff) | |
download | lwn-1f94ea8181a9305a5d5cf635a6a4e9ac8ee3d2c3.tar.gz lwn-1f94ea8181a9305a5d5cf635a6a4e9ac8ee3d2c3.zip |
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 <jasowang@redhat.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Acked-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/hv/vmbus_drv.c | 25 |
1 files changed, 2 insertions, 23 deletions
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index f40dd57bbec1..8e1a9ec53003 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -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); |