1 files changed, 77 insertions, 7 deletions

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 69782df3617f..222f0e894a0c 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1368,6 +1368,65 @@ static int kvm_vm_release(struct inode *inode, struct file *filp)
 	return 0;
 }
 
+int kvm_trylock_all_vcpus(struct kvm *kvm)
+{
+	struct kvm_vcpu *vcpu;
+	unsigned long i, j;
+
+	lockdep_assert_held(&kvm->lock);
+
+	kvm_for_each_vcpu(i, vcpu, kvm)
+		if (!mutex_trylock_nest_lock(&vcpu->mutex, &kvm->lock))
+			goto out_unlock;
+	return 0;
+
+out_unlock:
+	kvm_for_each_vcpu(j, vcpu, kvm) {
+		if (i == j)
+			break;
+		mutex_unlock(&vcpu->mutex);
+	}
+	return -EINTR;
+}
+EXPORT_SYMBOL_GPL(kvm_trylock_all_vcpus);
+
+int kvm_lock_all_vcpus(struct kvm *kvm)
+{
+	struct kvm_vcpu *vcpu;
+	unsigned long i, j;
+	int r;
+
+	lockdep_assert_held(&kvm->lock);
+
+	kvm_for_each_vcpu(i, vcpu, kvm) {
+		r = mutex_lock_killable_nest_lock(&vcpu->mutex, &kvm->lock);
+		if (r)
+			goto out_unlock;
+	}
+	return 0;
+
+out_unlock:
+	kvm_for_each_vcpu(j, vcpu, kvm) {
+		if (i == j)
+			break;
+		mutex_unlock(&vcpu->mutex);
+	}
+	return r;
+}
+EXPORT_SYMBOL_GPL(kvm_lock_all_vcpus);
+
+void kvm_unlock_all_vcpus(struct kvm *kvm)
+{
+	struct kvm_vcpu *vcpu;
+	unsigned long i;
+
+	lockdep_assert_held(&kvm->lock);
+
+	kvm_for_each_vcpu(i, vcpu, kvm)
+		mutex_unlock(&vcpu->mutex);
+}
+EXPORT_SYMBOL_GPL(kvm_unlock_all_vcpus);
+
 /*
  * Allocation size is twice as large as the actual dirty bitmap size.
  * See kvm_vm_ioctl_get_dirty_log() why this is needed.
@@ -2513,6 +2572,8 @@ static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
 		r = xa_reserve(&kvm->mem_attr_array, i, GFP_KERNEL_ACCOUNT);
 		if (r)
 			goto out_unlock;
+
+		cond_resched();
 	}
 
 	kvm_handle_gfn_range(kvm, &pre_set_range);
@@ -2521,6 +2582,7 @@ static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
 		r = xa_err(xa_store(&kvm->mem_attr_array, i, entry,
 				    GFP_KERNEL_ACCOUNT));
 		KVM_BUG_ON(r, kvm);
+		cond_resched();
 	}
 
 	kvm_handle_gfn_range(kvm, &post_set_range);
@@ -3739,7 +3801,7 @@ EXPORT_SYMBOL_GPL(kvm_vcpu_wake_up);
 /*
  * Kick a sleeping VCPU, or a guest VCPU in guest mode, into host kernel mode.
  */
-void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
+void __kvm_vcpu_kick(struct kvm_vcpu *vcpu, bool wait)
 {
 	int me, cpu;
 
@@ -3768,13 +3830,24 @@ void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
 	 */
 	if (kvm_arch_vcpu_should_kick(vcpu)) {
 		cpu = READ_ONCE(vcpu->cpu);
-		if (cpu != me && (unsigned)cpu < nr_cpu_ids && cpu_online(cpu))
-			smp_send_reschedule(cpu);
+		if (cpu != me && (unsigned int)cpu < nr_cpu_ids && cpu_online(cpu)) {
+			/*
+			 * Use a reschedule IPI to kick the vCPU if the caller
+			 * doesn't need to wait for a response, as KVM allows
+			 * kicking vCPUs while IRQs are disabled, but using the
+			 * SMP function call framework with IRQs disabled can
+			 * deadlock due to taking cross-CPU locks.
+			 */
+			if (wait)
+				smp_call_function_single(cpu, ack_kick, NULL, wait);
+			else
+				smp_send_reschedule(cpu);
+		}
 	}
 out:
 	put_cpu();
 }
-EXPORT_SYMBOL_GPL(kvm_vcpu_kick);
+EXPORT_SYMBOL_GPL(__kvm_vcpu_kick);
 #endif /* !CONFIG_S390 */
 
 int kvm_vcpu_yield_to(struct kvm_vcpu *target)
@@ -5765,7 +5838,6 @@ static int __kvm_io_bus_write(struct kvm_vcpu *vcpu, struct kvm_io_bus *bus,
 	return -EOPNOTSUPP;
 }
 
-/* kvm_io_bus_write - called under kvm->slots_lock */
 int kvm_io_bus_write(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx, gpa_t addr,
 		     int len, const void *val)
 {
@@ -5786,7 +5858,6 @@ int kvm_io_bus_write(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx, gpa_t addr,
 }
 EXPORT_SYMBOL_GPL(kvm_io_bus_write);
 
-/* kvm_io_bus_write_cookie - called under kvm->slots_lock */
 int kvm_io_bus_write_cookie(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx,
 			    gpa_t addr, int len, const void *val, long cookie)
 {
@@ -5836,7 +5907,6 @@ static int __kvm_io_bus_read(struct kvm_vcpu *vcpu, struct kvm_io_bus *bus,
 	return -EOPNOTSUPP;
 }
 
-/* kvm_io_bus_read - called under kvm->slots_lock */
 int kvm_io_bus_read(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx, gpa_t addr,
 		    int len, void *val)
 {