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| author | Vitaly Kuznetsov <vkuznets@redhat.com> | 2015-02-27 11:25:51 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-03-01 19:29:05 -0800 |
| commit | e513229b4c386e6c9f66298c13fde92f73e6e1ac (patch) | |
| tree | aff1c8f388eb5260f1c91f6acaee54129c53a315 | |
| parent | c517d838eb7d07bbe9507871fab3931deccff539 (diff) | |
| download | linux-e513229b4c386e6c9f66298c13fde92f73e6e1ac.tar.bz2 | |
Drivers: hv: vmbus: prevent cpu offlining on newer hypervisors
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@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/hv/vmbus_drv.c | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index f518b8d7a5b5..3b18a665ef4c 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -33,6 +33,7 @@ #include <linux/hyperv.h> #include <linux/kernel_stat.h> #include <linux/clockchips.h> +#include <linux/cpu.h> #include <asm/hyperv.h> #include <asm/hypervisor.h> #include <asm/mshyperv.h> @@ -704,6 +705,39 @@ static void vmbus_isr(void) } } +#ifdef CONFIG_HOTPLUG_CPU +static int hyperv_cpu_disable(void) +{ + return -ENOSYS; +} + +static void hv_cpu_hotplug_quirk(bool vmbus_loaded) +{ + static void *previous_cpu_disable; + + /* + * Offlining a CPU when running on newer hypervisors (WS2012R2, Win8, + * ...) is not supported at this moment as channel interrupts are + * distributed across all of them. + */ + + if ((vmbus_proto_version == VERSION_WS2008) || + (vmbus_proto_version == VERSION_WIN7)) + return; + + if (vmbus_loaded) { + previous_cpu_disable = smp_ops.cpu_disable; + smp_ops.cpu_disable = hyperv_cpu_disable; + pr_notice("CPU offlining is not supported by hypervisor\n"); + } else if (previous_cpu_disable) + smp_ops.cpu_disable = previous_cpu_disable; +} +#else +static void hv_cpu_hotplug_quirk(bool vmbus_loaded) +{ +} +#endif + /* * vmbus_bus_init -Main vmbus driver initialization routine. * @@ -744,6 +778,7 @@ static int vmbus_bus_init(int irq) if (ret) goto err_alloc; + hv_cpu_hotplug_quirk(true); vmbus_request_offers(); return 0; @@ -997,6 +1032,7 @@ static void __exit vmbus_exit(void) bus_unregister(&hv_bus); hv_cleanup(); acpi_bus_unregister_driver(&vmbus_acpi_driver); + hv_cpu_hotplug_quirk(false); } |