KVM: s390: make use of ipte lock
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>
diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c
index 916e1ee..691fdb7 100644
--- a/arch/s390/kvm/gaccess.c
+++ b/arch/s390/kvm/gaccess.c
@@ -207,6 +207,107 @@
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 @@
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 @@
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 @@
ga += _len;
data += _len;
}
+ if (need_ipte_lock)
+ ipte_unlock(vcpu);
if (nr_pages > ARRAY_SIZE(pages_array))
vfree(pages);
return rc;