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KVM: s390: Make the simple ipte mutex specific to a VM instead of global

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The ipte-locking should be done for each VM seperately, not globally.
This way we avoid possible congestions when the simple ipte-lock is used
and multiple VMs are running.

Suggested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This commit is contained in:
Thomas Huth 2014-10-01 14:48:42 +02:00 committed by Christian Borntraeger
parent cac7f24298
commit a6b7e459ff
3 changed files with 12 additions and 11 deletions
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2
arch/s390/include/asm/kvm_host.h
View file

@ -434,6 +434,8 @@ struct kvm_arch{
int user_cpu_state_ctrl;
struct s390_io_adapter *adapters[MAX_S390_IO_ADAPTERS];
wait_queue_head_t ipte_wq;
int ipte_lock_count;
struct mutex ipte_mutex;
spinlock_t start_stop_lock;
struct kvm_s390_crypto crypto;
};

20
arch/s390/kvm/gaccess.c
View file

@ -207,8 +207,6 @@ 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)
{
@ -216,16 +214,16 @@ int ipte_lock_held(struct kvm_vcpu *vcpu)
if (vcpu->arch.sie_block->eca & 1)
return ic->kh != 0;
return ipte_lock_count != 0;
return vcpu->kvm->arch.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)
mutex_lock(&vcpu->kvm->arch.ipte_mutex);
vcpu->kvm->arch.ipte_lock_count++;
if (vcpu->kvm->arch.ipte_lock_count > 1)
goto out;
ic = &vcpu->kvm->arch.sca->ipte_control;
do {
@ -238,16 +236,16 @@ static void ipte_lock_simple(struct kvm_vcpu *vcpu)
new.k = 1;
} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
out:
mutex_unlock(&ipte_mutex);
mutex_unlock(&vcpu->kvm->arch.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)
mutex_lock(&vcpu->kvm->arch.ipte_mutex);
vcpu->kvm->arch.ipte_lock_count--;
if (vcpu->kvm->arch.ipte_lock_count)
goto out;
ic = &vcpu->kvm->arch.sca->ipte_control;
do {
@ -256,7 +254,7 @@ static void ipte_unlock_simple(struct kvm_vcpu *vcpu)
} while (cmpxchg(&ic->val, old.val, new.val) != old.val);
wake_up(&vcpu->kvm->arch.ipte_wq);
out:
mutex_unlock(&ipte_mutex);
mutex_unlock(&vcpu->kvm->arch.ipte_mutex);
}
static void ipte_lock_siif(struct kvm_vcpu *vcpu)

1
arch/s390/kvm/kvm-s390.c
View file

@ -453,6 +453,7 @@ 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);
mutex_init(&kvm->arch.ipte_mutex);
debug_register_view(kvm->arch.dbf, &debug_sprintf_view);
VM_EVENT(kvm, 3, "%s", "vm created");