diff options
Diffstat (limited to 'drivers/kvm/kvm_main.c')
| -rw-r--r-- | drivers/kvm/kvm_main.c | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c index a6cd1c1fe29..291d298868f 100644 --- a/drivers/kvm/kvm_main.c +++ b/drivers/kvm/kvm_main.c @@ -34,6 +34,7 @@ #include <linux/highmem.h> #include <linux/file.h> #include <asm/desc.h> +#include <linux/cpu.h> #include "x86_emulate.h" #include "segment_descriptor.h" @@ -2039,6 +2040,64 @@ static struct notifier_block kvm_reboot_notifier = { .priority = 0, }; +/* + * Make sure that a cpu that is being hot-unplugged does not have any vcpus + * cached on it. + */ +static void decache_vcpus_on_cpu(int cpu) +{ + struct kvm *vm; + struct kvm_vcpu *vcpu; + int i; + + spin_lock(&kvm_lock); + list_for_each_entry(vm, &vm_list, vm_list) + for (i = 0; i < KVM_MAX_VCPUS; ++i) { + vcpu = &vm->vcpus[i]; + /* + * If the vcpu is locked, then it is running on some + * other cpu and therefore it is not cached on the + * cpu in question. + * + * If it's not locked, check the last cpu it executed + * on. + */ + if (mutex_trylock(&vcpu->mutex)) { + if (vcpu->cpu == cpu) { + kvm_arch_ops->vcpu_decache(vcpu); + vcpu->cpu = -1; + } + mutex_unlock(&vcpu->mutex); + } + } + spin_unlock(&kvm_lock); +} + +static int kvm_cpu_hotplug(struct notifier_block *notifier, unsigned long val, + void *v) +{ + int cpu = (long)v; + + switch (val) { + case CPU_DEAD: + case CPU_UP_CANCELED: + decache_vcpus_on_cpu(cpu); + smp_call_function_single(cpu, kvm_arch_ops->hardware_disable, + NULL, 0, 1); + break; + case CPU_UP_PREPARE: + smp_call_function_single(cpu, kvm_arch_ops->hardware_enable, + NULL, 0, 1); + break; + } + return NOTIFY_OK; +} + +static struct notifier_block kvm_cpu_notifier = { + .notifier_call = kvm_cpu_hotplug, + .priority = 20, /* must be > scheduler priority */ +}; + static __init void kvm_init_debug(void) { struct kvm_stats_debugfs_item *p; @@ -2085,6 +2144,9 @@ int kvm_init_arch(struct kvm_arch_ops *ops, struct module *module) return r; on_each_cpu(kvm_arch_ops->hardware_enable, NULL, 0, 1); + r = register_cpu_notifier(&kvm_cpu_notifier); + if (r) + goto out_free_1; register_reboot_notifier(&kvm_reboot_notifier); kvm_chardev_ops.owner = module; @@ -2099,6 +2161,8 @@ int kvm_init_arch(struct kvm_arch_ops *ops, struct module *module) out_free: unregister_reboot_notifier(&kvm_reboot_notifier); + unregister_cpu_notifier(&kvm_cpu_notifier); +out_free_1: on_each_cpu(kvm_arch_ops->hardware_disable, NULL, 0, 1); kvm_arch_ops->hardware_unsetup(); return r; |