From 8a242234b4bfed37f7fbd9b0b16f8088f31ca140 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Fri, 10 Jan 2014 14:33:28 +0100 Subject: [PATCH] KVM: s390: make use of ipte lock Signed-off-by: Heiko Carstens Reviewed-by: Thomas Huth Signed-off-by: Christian Borntraeger --- arch/s390/include/asm/kvm_host.h | 12 +++- arch/s390/kvm/gaccess.c | 109 +++++++++++++++++++++++++++++++ arch/s390/kvm/gaccess.h | 2 + arch/s390/kvm/kvm-s390.c | 2 + arch/s390/kvm/priv.c | 18 +++++ 5 files changed, 142 insertions(+), 1 deletion(-) diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index c290d443d2c1..f1ed7bdba733 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -39,9 +39,17 @@ struct sca_entry { __u64 reserved2[2]; } __attribute__((packed)); +union ipte_control { + unsigned long val; + struct { + unsigned long k : 1; + unsigned long kh : 31; + unsigned long kg : 32; + }; +}; struct sca_block { - __u64 ipte_control; + union ipte_control ipte_control; __u64 reserved[5]; __u64 mcn; __u64 reserved2; @@ -167,6 +175,7 @@ struct kvm_vcpu_stat { u32 instruction_stpx; u32 instruction_stap; u32 instruction_storage_key; + u32 instruction_ipte_interlock; u32 instruction_stsch; u32 instruction_chsc; u32 instruction_stsi; @@ -336,6 +345,7 @@ struct kvm_arch{ int use_irqchip; int use_cmma; struct s390_io_adapter *adapters[MAX_S390_IO_ADAPTERS]; + wait_queue_head_t ipte_wq; }; #define KVM_HVA_ERR_BAD (-1UL) diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c index 916e1ee1f8c9..691fdb776c90 100644 --- a/arch/s390/kvm/gaccess.c +++ b/arch/s390/kvm/gaccess.c @@ -207,6 +207,107 @@ union raddress { unsigned long pfra : 52; /* Page-Frame Real Address */ }; +static int ipte_lock_count; +static DEFINE_MUTEX(ipte_mutex); + +int ipte_lock_held(struct kvm_vcpu *vcpu) +{ + union ipte_control *ic = &vcpu->kvm->arch.sca->ipte_control; + + if (vcpu->arch.sie_block->eca & 1) + return ic->kh != 0; + return ipte_lock_count != 0; +} + +static void ipte_lock_simple(struct kvm_vcpu *vcpu) +{ + union ipte_control old, new, *ic; + + mutex_lock(&ipte_mutex); + ipte_lock_count++; + if (ipte_lock_count > 1) + goto out; + ic = &vcpu->kvm->arch.sca->ipte_control; + do { + old = ACCESS_ONCE(*ic); + while (old.k) { + cond_resched(); + old = ACCESS_ONCE(*ic); + } + new = old; + new.k = 1; + } while (cmpxchg(&ic->val, old.val, new.val) != old.val); +out: + mutex_unlock(&ipte_mutex); +} + +static void ipte_unlock_simple(struct kvm_vcpu *vcpu) +{ + union ipte_control old, new, *ic; + + mutex_lock(&ipte_mutex); + ipte_lock_count--; + if (ipte_lock_count) + goto out; + ic = &vcpu->kvm->arch.sca->ipte_control; + do { + new = old = ACCESS_ONCE(*ic); + new.k = 0; + } while (cmpxchg(&ic->val, old.val, new.val) != old.val); + if (!ipte_lock_count) + wake_up(&vcpu->kvm->arch.ipte_wq); +out: + mutex_unlock(&ipte_mutex); +} + +static void ipte_lock_siif(struct kvm_vcpu *vcpu) +{ + union ipte_control old, new, *ic; + + ic = &vcpu->kvm->arch.sca->ipte_control; + do { + old = ACCESS_ONCE(*ic); + while (old.kg) { + cond_resched(); + old = ACCESS_ONCE(*ic); + } + new = old; + new.k = 1; + new.kh++; + } while (cmpxchg(&ic->val, old.val, new.val) != old.val); +} + +static void ipte_unlock_siif(struct kvm_vcpu *vcpu) +{ + union ipte_control old, new, *ic; + + ic = &vcpu->kvm->arch.sca->ipte_control; + do { + new = old = ACCESS_ONCE(*ic); + new.kh--; + if (!new.kh) + new.k = 0; + } while (cmpxchg(&ic->val, old.val, new.val) != old.val); + if (!new.kh) + wake_up(&vcpu->kvm->arch.ipte_wq); +} + +static void ipte_lock(struct kvm_vcpu *vcpu) +{ + if (vcpu->arch.sie_block->eca & 1) + ipte_lock_siif(vcpu); + else + ipte_lock_simple(vcpu); +} + +static void ipte_unlock(struct kvm_vcpu *vcpu) +{ + if (vcpu->arch.sie_block->eca & 1) + ipte_unlock_siif(vcpu); + else + ipte_unlock_simple(vcpu); +} + static unsigned long get_vcpu_asce(struct kvm_vcpu *vcpu) { switch (psw_bits(vcpu->arch.sie_block->gpsw).as) { @@ -485,6 +586,8 @@ int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, void *data, unsigned long _len, nr_pages, gpa, idx; unsigned long pages_array[2]; unsigned long *pages; + int need_ipte_lock; + union asce asce; int rc; if (!len) @@ -498,6 +601,10 @@ int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, void *data, pages = vmalloc(nr_pages * sizeof(unsigned long)); if (!pages) return -ENOMEM; + asce.val = get_vcpu_asce(vcpu); + need_ipte_lock = psw_bits(*psw).t && !asce.r; + if (need_ipte_lock) + ipte_lock(vcpu); rc = guest_page_range(vcpu, ga, pages, nr_pages, write); for (idx = 0; idx < nr_pages && !rc; idx++) { gpa = *(pages + idx) + (ga & ~PAGE_MASK); @@ -510,6 +617,8 @@ int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, void *data, ga += _len; data += _len; } + if (need_ipte_lock) + ipte_unlock(vcpu); if (nr_pages > ARRAY_SIZE(pages_array)) vfree(pages); return rc; diff --git a/arch/s390/kvm/gaccess.h b/arch/s390/kvm/gaccess.h index 21ee62cd948e..f46e764c5b43 100644 --- a/arch/s390/kvm/gaccess.h +++ b/arch/s390/kvm/gaccess.h @@ -397,4 +397,6 @@ int read_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data, return access_guest_real(vcpu, gra, data, len, 0); } +int ipte_lock_held(struct kvm_vcpu *vcpu); + #endif /* __KVM_S390_GACCESS_H */ diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 927ba7361da9..e1dfe2461d4b 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -67,6 +67,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { { "instruction_stpx", VCPU_STAT(instruction_stpx) }, { "instruction_stap", VCPU_STAT(instruction_stap) }, { "instruction_storage_key", VCPU_STAT(instruction_storage_key) }, + { "instruction_ipte_interlock", VCPU_STAT(instruction_ipte_interlock) }, { "instruction_stsch", VCPU_STAT(instruction_stsch) }, { "instruction_chsc", VCPU_STAT(instruction_chsc) }, { "instruction_essa", VCPU_STAT(instruction_essa) }, @@ -437,6 +438,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) spin_lock_init(&kvm->arch.float_int.lock); INIT_LIST_HEAD(&kvm->arch.float_int.list); + init_waitqueue_head(&kvm->arch.ipte_wq); debug_register_view(kvm->arch.dbf, &debug_sprintf_view); VM_EVENT(kvm, 3, "%s", "vm created"); diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c index 9a04d74c5fb4..4792f1df921a 100644 --- a/arch/s390/kvm/priv.c +++ b/arch/s390/kvm/priv.c @@ -173,6 +173,19 @@ static int handle_skey(struct kvm_vcpu *vcpu) return 0; } +static int handle_ipte_interlock(struct kvm_vcpu *vcpu) +{ + psw_t *psw = &vcpu->arch.sie_block->gpsw; + + vcpu->stat.instruction_ipte_interlock++; + if (psw_bits(*psw).p) + return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP); + wait_event(vcpu->kvm->arch.ipte_wq, !ipte_lock_held(vcpu)); + psw->addr = __rewind_psw(*psw, 4); + VCPU_EVENT(vcpu, 4, "%s", "retrying ipte interlock operation"); + return 0; +} + static int handle_test_block(struct kvm_vcpu *vcpu) { unsigned long hva; @@ -509,6 +522,7 @@ static const intercept_handler_t b2_handlers[256] = { [0x10] = handle_set_prefix, [0x11] = handle_store_prefix, [0x12] = handle_store_cpu_address, + [0x21] = handle_ipte_interlock, [0x29] = handle_skey, [0x2a] = handle_skey, [0x2b] = handle_skey, @@ -526,6 +540,7 @@ static const intercept_handler_t b2_handlers[256] = { [0x3a] = handle_io_inst, [0x3b] = handle_io_inst, [0x3c] = handle_io_inst, + [0x50] = handle_ipte_interlock, [0x5f] = handle_io_inst, [0x74] = handle_io_inst, [0x76] = handle_io_inst, @@ -686,7 +701,10 @@ static int handle_essa(struct kvm_vcpu *vcpu) } static const intercept_handler_t b9_handlers[256] = { + [0x8a] = handle_ipte_interlock, [0x8d] = handle_epsw, + [0x8e] = handle_ipte_interlock, + [0x8f] = handle_ipte_interlock, [0xab] = handle_essa, [0xaf] = handle_pfmf, }; -- 2.20.1