> -----Original Message----- > From: Jason Wang [mailto:jasowang@xxxxxxxxxx] > Sent: Friday, August 31, 2012 1:33 AM > To: devel@xxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx > Cc: Jason Wang; KY Srinivasan; Haiyang Zhang > 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. > > Cc: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx> > Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> > Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx> Thanks Jason. Acked-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx> > --- > 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 f40dd57..8e1a9ec 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); > -- > 1.7.1 > > > _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
