diff options
Diffstat (limited to 'arch/s390/kvm/kvm-s390.c')
| -rw-r--r-- | arch/s390/kvm/kvm-s390.c | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 924b1ae86caf..4bdb860b5c49 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -28,6 +28,7 @@ #include <linux/vmalloc.h> #include <asm/asm-offsets.h> #include <asm/lowcore.h> +#include <asm/etr.h> #include <asm/pgtable.h> #include <asm/nmi.h> #include <asm/switch_to.h> @@ -138,16 +139,47 @@ int kvm_arch_hardware_enable(void) static void kvm_gmap_notifier(struct gmap *gmap, unsigned long address); +/* + * This callback is executed during stop_machine(). All CPUs are therefore + * temporarily stopped. In order not to change guest behavior, we have to + * disable preemption whenever we touch the epoch of kvm and the VCPUs, + * so a CPU won't be stopped while calculating with the epoch. + */ +static int kvm_clock_sync(struct notifier_block *notifier, unsigned long val, + void *v) +{ + struct kvm *kvm; + struct kvm_vcpu *vcpu; + int i; + unsigned long long *delta = v; + + list_for_each_entry(kvm, &vm_list, vm_list) { + kvm->arch.epoch -= *delta; + kvm_for_each_vcpu(i, vcpu, kvm) { + vcpu->arch.sie_block->epoch -= *delta; + } + } + return NOTIFY_OK; +} + +static struct notifier_block kvm_clock_notifier = { + .notifier_call = kvm_clock_sync, +}; + int kvm_arch_hardware_setup(void) { gmap_notifier.notifier_call = kvm_gmap_notifier; gmap_register_ipte_notifier(&gmap_notifier); + atomic_notifier_chain_register(&s390_epoch_delta_notifier, + &kvm_clock_notifier); return 0; } void kvm_arch_hardware_unsetup(void) { gmap_unregister_ipte_notifier(&gmap_notifier); + atomic_notifier_chain_unregister(&s390_epoch_delta_notifier, + &kvm_clock_notifier); } int kvm_arch_init(void *opaque) @@ -501,11 +533,13 @@ static int kvm_s390_set_tod_low(struct kvm *kvm, struct kvm_device_attr *attr) return r; mutex_lock(&kvm->lock); + preempt_disable(); kvm->arch.epoch = gtod - host_tod; kvm_s390_vcpu_block_all(kvm); kvm_for_each_vcpu(vcpu_idx, cur_vcpu, kvm) cur_vcpu->arch.sie_block->epoch = kvm->arch.epoch; kvm_s390_vcpu_unblock_all(kvm); + preempt_enable(); mutex_unlock(&kvm->lock); VM_EVENT(kvm, 3, "SET: TOD base: 0x%llx\n", gtod); return 0; @@ -553,7 +587,9 @@ static int kvm_s390_get_tod_low(struct kvm *kvm, struct kvm_device_attr *attr) if (r) return r; + preempt_disable(); gtod = host_tod + kvm->arch.epoch; + preempt_enable(); if (copy_to_user((void __user *)attr->addr, >od, sizeof(gtod))) return -EFAULT; VM_EVENT(kvm, 3, "QUERY: TOD base: 0x%llx\n", gtod); @@ -1314,7 +1350,9 @@ static void kvm_s390_vcpu_initial_reset(struct kvm_vcpu *vcpu) void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu) { mutex_lock(&vcpu->kvm->lock); + preempt_disable(); vcpu->arch.sie_block->epoch = vcpu->kvm->arch.epoch; + preempt_enable(); mutex_unlock(&vcpu->kvm->lock); if (!kvm_is_ucontrol(vcpu->kvm)) vcpu->arch.gmap = vcpu->kvm->arch.gmap; |