diff options
| author | Vitaly Kuznetsov <vkuznets@redhat.com> | 2015-02-27 22:25:51 +0300 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2016-05-03 08:45:09 +0300 |
| commit | 76be64a958b56361329e41c61f6dda30c2af96f7 (patch) | |
| tree | 3cadf92c1f738d1394df7bbcb6157d82cc9f16ec | |
| parent | c7ecfa39d66c62ee662ae6906a2eec3d28a96e6a (diff) | |
| download | linux-76be64a958b56361329e41c61f6dda30c2af96f7.tar.xz | |
Drivers: hv: vmbus: prevent cpu offlining on newer hypervisors
commit e513229b4c386e6c9f66298c13fde92f73e6e1ac upstream.
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>
[ 3chas3@gmail.com: rebase to 3.14-stable ]
Signed-off-by: Chas Williams <3chas3@gmail.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
| -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 f9fe46f52cfa..d13f3dda6769 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -32,6 +32,7 @@ #include <linux/acpi.h> #include <acpi/acpi_bus.h> #include <linux/completion.h> +#include <linux/cpu.h> #include <linux/hyperv.h> #include <linux/kernel_stat.h> #include <asm/hyperv.h> @@ -517,6 +518,39 @@ static void vmbus_flow_handler(unsigned int irq, struct irq_desc *desc) desc->action->handler(irq, desc->action->dev_id); } +#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. * @@ -575,6 +609,7 @@ static int vmbus_bus_init(int irq) if (ret) goto err_alloc; + hv_cpu_hotplug_quirk(true); vmbus_request_offers(); return 0; @@ -812,6 +847,7 @@ static void __exit vmbus_exit(void) bus_unregister(&hv_bus); hv_cleanup(); acpi_bus_unregister_driver(&vmbus_acpi_driver); + hv_cpu_hotplug_quirk(false); } |