diff options
| -rw-r--r-- | arch/s390/kvm/kvm-s390.c | 19 | ||||
| -rw-r--r-- | arch/s390/kvm/kvm-s390.h | 4 | ||||
| -rw-r--r-- | arch/s390/kvm/priv.c | 15 |
3 files changed, 32 insertions, 6 deletions
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index b5ea95cf8686..b53ff693b66e 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -3961,14 +3961,12 @@ retry: return 0; } -void kvm_s390_set_tod_clock(struct kvm *kvm, - const struct kvm_s390_vm_tod_clock *gtod) +static void __kvm_s390_set_tod_clock(struct kvm *kvm, const struct kvm_s390_vm_tod_clock *gtod) { struct kvm_vcpu *vcpu; union tod_clock clk; unsigned long i; - mutex_lock(&kvm->lock); preempt_disable(); store_tod_clock_ext(&clk); @@ -3989,7 +3987,22 @@ void kvm_s390_set_tod_clock(struct kvm *kvm, kvm_s390_vcpu_unblock_all(kvm); preempt_enable(); +} + +void kvm_s390_set_tod_clock(struct kvm *kvm, const struct kvm_s390_vm_tod_clock *gtod) +{ + mutex_lock(&kvm->lock); + __kvm_s390_set_tod_clock(kvm, gtod); + mutex_unlock(&kvm->lock); +} + +int kvm_s390_try_set_tod_clock(struct kvm *kvm, const struct kvm_s390_vm_tod_clock *gtod) +{ + if (!mutex_trylock(&kvm->lock)) + return 0; + __kvm_s390_set_tod_clock(kvm, gtod); mutex_unlock(&kvm->lock); + return 1; } /** diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h index 4ba8fc30d87a..798955b62fa3 100644 --- a/arch/s390/kvm/kvm-s390.h +++ b/arch/s390/kvm/kvm-s390.h @@ -358,8 +358,8 @@ int kvm_s390_handle_sigp(struct kvm_vcpu *vcpu); int kvm_s390_handle_sigp_pei(struct kvm_vcpu *vcpu); /* implemented in kvm-s390.c */ -void kvm_s390_set_tod_clock(struct kvm *kvm, - const struct kvm_s390_vm_tod_clock *gtod); +void kvm_s390_set_tod_clock(struct kvm *kvm, const struct kvm_s390_vm_tod_clock *gtod); +int kvm_s390_try_set_tod_clock(struct kvm *kvm, const struct kvm_s390_vm_tod_clock *gtod); long kvm_arch_fault_in_page(struct kvm_vcpu *vcpu, gpa_t gpa, int writable); int kvm_s390_store_status_unloaded(struct kvm_vcpu *vcpu, unsigned long addr); int kvm_s390_vcpu_store_status(struct kvm_vcpu *vcpu, unsigned long addr); diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c index 30b24c42ef99..5beb7a4a11b3 100644 --- a/arch/s390/kvm/priv.c +++ b/arch/s390/kvm/priv.c @@ -102,7 +102,20 @@ static int handle_set_clock(struct kvm_vcpu *vcpu) return kvm_s390_inject_prog_cond(vcpu, rc); VCPU_EVENT(vcpu, 3, "SCK: setting guest TOD to 0x%llx", gtod.tod); - kvm_s390_set_tod_clock(vcpu->kvm, >od); + /* + * To set the TOD clock the kvm lock must be taken, but the vcpu lock + * is already held in handle_set_clock. The usual lock order is the + * opposite. As SCK is deprecated and should not be used in several + * cases, for example when the multiple epoch facility or TOD clock + * steering facility is installed (see Principles of Operation), a + * slow path can be used. If the lock can not be taken via try_lock, + * the instruction will be retried via -EAGAIN at a later point in + * time. + */ + if (!kvm_s390_try_set_tod_clock(vcpu->kvm, >od)) { + kvm_s390_retry_instr(vcpu); + return -EAGAIN; + } kvm_s390_set_psw_cc(vcpu, 0); return 0; |