diff options
| -rw-r--r-- | arch/s390/include/asm/kvm_host.h | 1 | ||||
| -rw-r--r-- | arch/s390/kernel/sthyi.c | 84 | ||||
| -rw-r--r-- | arch/s390/kvm/intercept.c | 10 | ||||
| -rw-r--r-- | arch/s390/kvm/kvm-s390.c | 2 |
4 files changed, 71 insertions, 26 deletions
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index 51375e766e90..fd006a272024 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -736,7 +736,6 @@ struct kvm_arch{ wait_queue_head_t ipte_wq; int ipte_lock_count; struct mutex ipte_mutex; - struct ratelimit_state sthyi_limit; spinlock_t start_stop_lock; struct sie_page2 *sie_page2; struct kvm_s390_cpu_model model; diff --git a/arch/s390/kernel/sthyi.c b/arch/s390/kernel/sthyi.c index 3d51f86f9dec..27e3c3d87379 100644 --- a/arch/s390/kernel/sthyi.c +++ b/arch/s390/kernel/sthyi.c @@ -11,7 +11,6 @@ #include <linux/errno.h> #include <linux/pagemap.h> #include <linux/vmalloc.h> -#include <linux/ratelimit.h> #include <asm/asm-offsets.h> #include <asm/sclp.h> @@ -139,6 +138,21 @@ struct lpar_cpu_inf { struct cpu_inf ifl; }; +/* + * STHYI requires extensive locking in the higher hypervisors + * and is very computational/memory expensive. Therefore we + * cache the retrieved data whose valid period is 1s. + */ +#define CACHE_VALID_JIFFIES HZ + +struct sthyi_info { + void *info; + unsigned long end; +}; + +static DEFINE_MUTEX(sthyi_mutex); +static struct sthyi_info sthyi_cache; + static inline u64 cpu_id(u8 ctidx, void *diag224_buf) { return *((u64 *)(diag224_buf + (ctidx + 1) * DIAG204_CPU_NAME_LEN)); @@ -395,6 +409,47 @@ static int sthyi(u64 vaddr, u64 *rc) return cc; } +static int fill_dst(void *dst, u64 *rc) +{ + struct sthyi_sctns *sctns = (struct sthyi_sctns *)dst; + + /* + * If the facility is on, we don't want to emulate the instruction. + * We ask the hypervisor to provide the data. + */ + if (test_facility(74)) + return sthyi((u64)dst, rc); + + fill_hdr(sctns); + fill_stsi(sctns); + fill_diag(sctns); + *rc = 0; + return 0; +} + +static int sthyi_init_cache(void) +{ + if (sthyi_cache.info) + return 0; + sthyi_cache.info = (void *)get_zeroed_page(GFP_KERNEL); + if (!sthyi_cache.info) + return -ENOMEM; + sthyi_cache.end = jiffies - 1; /* expired */ + return 0; +} + +static int sthyi_update_cache(u64 *rc) +{ + int r; + + memset(sthyi_cache.info, 0, PAGE_SIZE); + r = fill_dst(sthyi_cache.info, rc); + if (r) + return r; + sthyi_cache.end = jiffies + CACHE_VALID_JIFFIES; + return r; +} + /* * sthyi_fill - Fill page with data returned by the STHYI instruction * @@ -409,20 +464,23 @@ static int sthyi(u64 vaddr, u64 *rc) */ int sthyi_fill(void *dst, u64 *rc) { - struct sthyi_sctns *sctns = (struct sthyi_sctns *)dst; - - /* - * If the facility is on, we don't want to emulate the instruction. - * We ask the hypervisor to provide the data. - */ - if (test_facility(74)) - return sthyi((u64)dst, rc); + int r; - fill_hdr(sctns); - fill_stsi(sctns); - fill_diag(sctns); + mutex_lock(&sthyi_mutex); + r = sthyi_init_cache(); + if (r) + goto out; + if (time_is_before_jiffies(sthyi_cache.end)) { + /* cache expired */ + r = sthyi_update_cache(rc); + if (r) + goto out; + } *rc = 0; - return 0; + memcpy(dst, sthyi_cache.info, PAGE_SIZE); +out: + mutex_unlock(&sthyi_mutex); + return r; } EXPORT_SYMBOL_GPL(sthyi_fill); diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c index 46adda5e2b2c..8fe034beb623 100644 --- a/arch/s390/kvm/intercept.c +++ b/arch/s390/kvm/intercept.c @@ -375,16 +375,6 @@ int handle_sthyi(struct kvm_vcpu *vcpu) if (!test_kvm_facility(vcpu->kvm, 74)) return kvm_s390_inject_program_int(vcpu, PGM_OPERATION); - /* - * STHYI requires extensive locking in the higher hypervisors - * and is very computational/memory expensive. Therefore we - * ratelimit the executions per VM. - */ - if (!__ratelimit(&vcpu->kvm->arch.sthyi_limit)) { - kvm_s390_retry_instr(vcpu); - return 0; - } - kvm_s390_get_regs_rre(vcpu, ®1, ®2); code = vcpu->run->s.regs.gprs[reg1]; addr = vcpu->run->s.regs.gprs[reg2]; diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 40d0a1a97889..de6a5b790da0 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -1884,8 +1884,6 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) rc = -ENOMEM; - ratelimit_state_init(&kvm->arch.sthyi_limit, 5 * HZ, 500); - kvm->arch.use_esca = 0; /* start with basic SCA */ if (!sclp.has_64bscao) alloc_flags |= GFP_DMA; |