Commit a6b7e459 authored by Thomas Huth's avatar Thomas Huth Committed by Christian Borntraeger
Browse files

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



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: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarThomas Huth <thuth@linux.vnet.ibm.com>
Acked-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent cac7f242

arch/s390/include/asm/kvm_host.h

+2 −0
Original line number Diff line number Diff line
@@ -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;

};

arch/s390/kvm/gaccess.c

+9 −11
Original line number Diff line number Diff line
@@ -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)

arch/s390/kvm/kvm-s390.c

+1 −0
Original line number Diff line number Diff line
@@ -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");

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