4 files changed, 53 insertions, 37 deletions

diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 1fc68d97be9d..1d0ad7d2d29a 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -739,6 +739,7 @@ struct gmap {
         struct mm_struct *mm;
         unsigned long *table;
         unsigned long asce;
+        void *private;
         struct list_head crst_list;
 };
 
diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
index b7d1b2edeeb3..f0b8be0cc08d 100644
--- a/arch/s390/kvm/intercept.c
+++ b/arch/s390/kvm/intercept.c
@@ -174,47 +174,12 @@ static int handle_stop(struct kvm_vcpu *vcpu)
 
 static int handle_validity(struct kvm_vcpu *vcpu)
 {
-        unsigned long vmaddr;
         int viwhy = vcpu->arch.sie_block->ipb >> 16;
-        int rc;
 
         vcpu->stat.exit_validity++;
         trace_kvm_s390_intercept_validity(vcpu, viwhy);
-        if (viwhy == 0x37) {
-                vmaddr = gmap_fault(vcpu->arch.sie_block->prefix,
-                                    vcpu->arch.gmap);
-                if (IS_ERR_VALUE(vmaddr)) {
-                        rc = -EOPNOTSUPP;
-                        goto out;
-                }
-                rc = fault_in_pages_writeable((char __user *) vmaddr,
-                         PAGE_SIZE);
-                if (rc) {
-                        /* user will receive sigsegv, exit to user */
-                        rc = -EOPNOTSUPP;
-                        goto out;
-                }
-                vmaddr = gmap_fault(vcpu->arch.sie_block->prefix + PAGE_SIZE,
-                                    vcpu->arch.gmap);
-                if (IS_ERR_VALUE(vmaddr)) {
-                        rc = -EOPNOTSUPP;
-                        goto out;
-                }
-                rc = fault_in_pages_writeable((char __user *) vmaddr,
-                         PAGE_SIZE);
-                if (rc) {
-                        /* user will receive sigsegv, exit to user */
-                        rc = -EOPNOTSUPP;
-                        goto out;
-                }
-        } else
-                rc = -EOPNOTSUPP;
-
-out:
-        if (rc)
-                VCPU_EVENT(vcpu, 2, "unhandled validity intercept code %d",
-                           viwhy);
-        return rc;
+        WARN_ONCE(true, "kvm: unhandled validity intercept 0x%x\n", viwhy);
+        return -EOPNOTSUPP;
 }
 
 static int handle_instruction(struct kvm_vcpu *vcpu)
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index ef4ef21f2c73..08227c1e816f 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -84,6 +84,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
 };
 
 static unsigned long long *facilities;
+static struct gmap_notifier gmap_notifier;
 
 /* Section: not file related */
 int kvm_arch_hardware_enable(void *garbage)
@@ -96,13 +97,18 @@ void kvm_arch_hardware_disable(void *garbage)
 {
 }
 
+static void kvm_gmap_notifier(struct gmap *gmap, unsigned long address);
+
 int kvm_arch_hardware_setup(void)
 {
+        gmap_notifier.notifier_call = kvm_gmap_notifier;
+        gmap_register_ipte_notifier(&gmap_notifier);
         return 0;
 }
 
 void kvm_arch_hardware_unsetup(void)
 {
+        gmap_unregister_ipte_notifier(&gmap_notifier);
 }
 
 void kvm_arch_check_processor_compat(void *rtn)
@@ -239,6 +245,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
                 kvm->arch.gmap = gmap_alloc(current->mm);
                 if (!kvm->arch.gmap)
                         goto out_nogmap;
+                kvm->arch.gmap->private = kvm;
         }
 
         kvm->arch.css_support = 0;
@@ -309,6 +316,7 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
                 vcpu->arch.gmap = gmap_alloc(current->mm);
                 if (!vcpu->arch.gmap)
                         return -ENOMEM;
+                vcpu->arch.gmap->private = vcpu->kvm;
                 return 0;
         }
 
@@ -482,6 +490,22 @@ void exit_sie_sync(struct kvm_vcpu *vcpu)
         exit_sie(vcpu);
 }
 
+static void kvm_gmap_notifier(struct gmap *gmap, unsigned long address)
+{
+        int i;
+        struct kvm *kvm = gmap->private;
+        struct kvm_vcpu *vcpu;
+
+        kvm_for_each_vcpu(i, vcpu, kvm) {
+                /* match against both prefix pages */
+                if (vcpu->arch.sie_block->prefix == (address & ~0x1000UL)) {
+                        VCPU_EVENT(vcpu, 2, "gmap notifier for %lx", address);
+                        kvm_make_request(KVM_REQ_MMU_RELOAD, vcpu);
+                        exit_sie_sync(vcpu);
+                }
+        }
+}
+
 int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
 {
         /* kvm common code refers to this, but never calls it */
@@ -634,6 +658,27 @@ int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
         return -EINVAL; /* not implemented yet */
 }
 
+static int kvm_s390_handle_requests(struct kvm_vcpu *vcpu)
+{
+        /*
+         * We use MMU_RELOAD just to re-arm the ipte notifier for the
+         * guest prefix page. gmap_ipte_notify will wait on the ptl lock.
+         * This ensures that the ipte instruction for this request has
+         * already finished. We might race against a second unmapper that
+         * wants to set the blocking bit. Lets just retry the request loop.
+         */
+        while (kvm_check_request(KVM_REQ_MMU_RELOAD, vcpu)) {
+                int rc;
+                rc = gmap_ipte_notify(vcpu->arch.gmap,
+                                      vcpu->arch.sie_block->prefix,
+                                      PAGE_SIZE * 2);
+                if (rc)
+                        return rc;
+                s390_vcpu_unblock(vcpu);
+        }
+        return 0;
+}
+
 static int __vcpu_run(struct kvm_vcpu *vcpu)
 {
         int rc;
@@ -649,6 +694,10 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
         if (!kvm_is_ucontrol(vcpu->kvm))
                 kvm_s390_deliver_pending_interrupts(vcpu);
 
+        rc = kvm_s390_handle_requests(vcpu);
+        if (rc)
+                return rc;
+
         vcpu->arch.sie_block->icptcode = 0;
         preempt_disable();
         kvm_guest_enter();
diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 7a8abfd26a0f..269b523d0f6e 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -63,6 +63,7 @@ static inline void kvm_s390_set_prefix(struct kvm_vcpu *vcpu, u32 prefix)
 {
         vcpu->arch.sie_block->prefix = prefix & 0x7fffe000u;
         vcpu->arch.sie_block->ihcpu  = 0xffff;
+        kvm_make_request(KVM_REQ_MMU_RELOAD, vcpu);
 }
 
 static inline u64 kvm_s390_get_base_disp_s(struct kvm_vcpu *vcpu)