> -----Original Message----- > From: Greg Kroah-Hartman [mailto:gregkh@xxxxxxxxxxxxxxxxxxx] > Sent: Monday, January 26, 2015 2:54 PM > To: Vitaly Kuznetsov > Cc: KY Srinivasan; devel@xxxxxxxxxxxxxxxxxxxxxx; Haiyang Zhang; linux- > kernel@xxxxxxxxxxxxxxx; Dexuan Cui > Subject: Re: [PATCH v3] Drivers: hv: vmbus: prevent cpu offlining on newer > hypervisors > > On Mon, Jan 26, 2015 at 11:38:54AM +0100, Vitaly Kuznetsov wrote: > > Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> writes: > > > > > On Mon, Jan 12, 2015 at 05:50:11PM +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> > > >> Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx> > > >> --- > > >> Changes since v2: > > >> - repair the build when vmbus is builded as a module [Greg KH] by > saving > > >> current cpu_disable pointer to previous_cpu_disable and restoring it > on > > >> unload; > > >> - return -ENOSYS (same as native_cpu_disable when > !CONFIG_HOTPLUG_CPU) instead > > >> of -1 in hyperv_cpu_disable(). > > >> > > >> Changes since v1: > > >> - introduce hv_cpu_hotplug_quirk() function to not spread #ifdefs > > >> [Greg KH]; > > >> - add pr_notice() message "hv_vmbus: CPU offlining is not supported by > > >> hypervisor". > > >> --- > > >> drivers/hv/vmbus_drv.c | 36 > ++++++++++++++++++++++++++++++++++++ > > >> 1 file changed, 36 insertions(+) > > > > > > Doesn't apply to my char-misc-test branch at all :( > > > > Another mid-air collision with K.Y's "Drivers: hv: vmbus: Implement a > > clockevent device", please use the attached version. No functional > > changes are required, I just fixed the merge conflict (includes). > > > > Othere than that (and sorry for meddling), would it it be better if > > you switch to 'pull requests' workflow with K.Y? There is a lot of > > ongoing work in hyperv nowdays and such collisions seem otherwise > > inevitable ... > > This is a trivial number of patches for this subsystem, so no, a git workflow > isn't needed. But if KY would collect the patches up and send them to me for > all hyperv patches from now on, that would make these types of issues go > away, KY, can you do that from now on? Will do. Thanks, K. Y > > thanks, > > greg k-h _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
