| Message ID | 20180116182700.1042-5-vkuznets@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, 16 Jan 2018, Vitaly Kuznetsov wrote: > It is very unlikely for CPUs to get offlined when we run on Hyper-V as > we have a protection in vmbus module which prevents it when we have any > VMBus devices assigned. This, however, may change in future if an option > to reassign an already active channel will be added. It is also possible > to run without any Hyper-V devices of have a CPU with no assigned channels. > > Reassign reenlightenment notifications to some other active CPU when > the CPU which is assigned to get them goes offline. > > Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index 712ac40081f7..e4377e2f2a10 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -191,6 +191,26 @@ void clear_hv_tscchange_cb(void) } EXPORT_SYMBOL_GPL(clear_hv_tscchange_cb); +static int hv_cpu_die(unsigned int cpu) +{ + struct hv_reenlightenment_control re_ctrl; + unsigned int new_cpu; + + if (hv_reenlightenment_cb == NULL) + return 0; + + rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl)); + if (re_ctrl.target_vp == hv_vp_index[cpu]) { + /* Reassign to some other online CPU */ + new_cpu = cpumask_any_but(cpu_online_mask, cpu); + + re_ctrl.target_vp = hv_vp_index[new_cpu]; + wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl)); + } + + return 0; +} + /* * This function is to be invoked early in the boot sequence after the * hypervisor has been detected. @@ -220,7 +240,7 @@ void hyperv_init(void) return; if (cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online", - hv_cpu_init, NULL) < 0) + hv_cpu_init, hv_cpu_die) < 0) goto free_vp_index; /*
It is very unlikely for CPUs to get offlined when we run on Hyper-V as we have a protection in vmbus module which prevents it when we have any VMBus devices assigned. This, however, may change in future if an option to reassign an already active channel will be added. It is also possible to run without any Hyper-V devices of have a CPU with no assigned channels. Reassign reenlightenment notifications to some other active CPU when the CPU which is assigned to get them goes offline. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> --- v2-> v3: - Drop spinlock protection from hv_cpu_die() as cpu hotplug is already serialized [Thomas Gleixner] - Use cpumask_any_but() in hv_cpu_die() [Thomas Gleixner] --- arch/x86/hyperv/hv_init.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-)