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KVM: s390: make use of ipte lock

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Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This commit is contained in:
Heiko Carstens 2014-01-10 14:33:28 +01:00 committed by Christian Borntraeger
parent 217a440683
commit 8a242234b4
5 changed files with 142 additions and 1 deletions
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12
arch/s390/include/asm/kvm_host.h
View File

@ -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)

109
arch/s390/kvm/gaccess.c
View File

@ -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;

2
arch/s390/kvm/gaccess.h
View File

@ -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 */

2
arch/s390/kvm/kvm-s390.c
View File

@ -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");

18
arch/s390/kvm/priv.c
View File

@ -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,
};