> -----Original Message----- > From: devel [mailto:driverdev-devel-bounces@xxxxxxxxxxxxxxxxxxxxxx] On > Behalf Of Greg Kroah-Hartman > Sent: Thursday, November 27, 2014 11:03 AM > To: Vitaly Kuznetsov > Cc: devel@xxxxxxxxxxxxxxxxxxxxxx; Haiyang Zhang; linux- > kernel@xxxxxxxxxxxxxxx > Subject: Re: [PATCH] Drivers: hv: vmbus: prevent cpu offlining on newer > hypervisors > > On Wed, Nov 26, 2014 at 02:52:22PM +0100, Vitaly Kuznetsov wrote: > > When an SMP Hyper-V guest is running on top of 2012R2 Server and > secondary > > cpus are sent offline (with echo 0 > > /sys/devices/system/cpu/cpu$cpu/online) > > the system freeze is observed. This happens due to the fact that on newer > > hypervisors (Win8, WS2012R2, ...) vmbus channel handlers are > distributed > > across all cpus (see init_vp_index() function in > drivers/hv/channel_mgmt.c) > > and on cpu offlining nobody reassigns them to CPU0. Prevent cpu > offlining > > when vmbus is loaded until the issue is fixed host-side. > > > > This patch also disables hibernation but it is OK as it is also broken (MCE > > error is hit on resume). Suspend still works. > > > > Tested with WS2008R2 and WS2012R2. > > > > Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> > > --- > > drivers/hv/vmbus_drv.c | 19 +++++++++++++++++++ > > 1 file changed, 19 insertions(+) > > > > diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c > > index 4d6b269..9a82249 100644 > > --- a/drivers/hv/vmbus_drv.c > > +++ b/drivers/hv/vmbus_drv.c > > @@ -32,6 +32,7 @@ > > #include <linux/completion.h> > > #include <linux/hyperv.h> > > #include <linux/kernel_stat.h> > > +#include <linux/cpu.h> > > #include <asm/hyperv.h> > > #include <asm/hypervisor.h> > > #include <asm/mshyperv.h> > > @@ -671,6 +672,13 @@ static void vmbus_isr(void) > > tasklet_schedule(&msg_dpc); > > } > > > > +#ifdef CONFIG_HOTPLUG_CPU > > +static int hyperv_cpu_disable(void) > > +{ > > + return -1; > > +} > > +#endif > > + > > /* > > * vmbus_bus_init -Main vmbus driver initialization routine. > > * > > @@ -711,6 +719,12 @@ static int vmbus_bus_init(int irq) > > if (ret) > > goto err_alloc; > > > > +#ifdef CONFIG_HOTPLUG_CPU > > + if ((vmbus_proto_version != VERSION_WS2008) && > > + (vmbus_proto_version != VERSION_WIN7)) > > + smp_ops.cpu_disable = hyperv_cpu_disable; > > +#endif > > + > > vmbus_request_offers(); > > > > return 0; > > @@ -964,6 +978,11 @@ static void __exit vmbus_exit(void) > > bus_unregister(&hv_bus); > > hv_cleanup(); > > acpi_bus_unregister_driver(&vmbus_acpi_driver); > > +#ifdef CONFIG_HOTPLUG_CPU > > + if ((vmbus_proto_version != VERSION_WS2008) && > > + (vmbus_proto_version != VERSION_WIN7)) > > + smp_ops.cpu_disable = native_cpu_disable; > > +#endif > > } > > #ifdef in a .c file is not a good idea to do if at all possible, please > only put this in one place, using a function call to "hide" the mess. > > greg k-h Hi Vitaly, The idea of the patch is good to me. I agree with Greg. BTW, maybe hv_cpu_hotplug_quirk() is a better name? Thanks, -- Dexuan _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
