KVM: Prepare for moving vcpu_load/vcpu_put into arch specific code

In preparation for moving calls to vcpu_load() and vcpu_put() into the
architecture specific implementations of the KVM vcpu ioctls, move the
calls in the main kvm_vcpu_ioctl() dispatcher function to each case
of the ioctl select statement.  This allows us to move the vcpu_load()
and vcpu_put() calls into architecture specific implementations of vcpu
ioctls, one by one.
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

virt/kvm/kvm_main.c

@@ -2556,13 +2556,13 @@ static long kvm_vcpu_ioctl(struct file *filp,
 
 	if (mutex_lock_killable(&vcpu->mutex))
 		return -EINTR;
-	vcpu_load(vcpu);
 	switch (ioctl) {
 	case KVM_RUN: {
 		struct pid *oldpid;
 		r = -EINVAL;
 		if (arg)
 			goto out;
+		vcpu_load(vcpu);
 		oldpid = rcu_access_pointer(vcpu->pid);
 		if (unlikely(oldpid != current->pids[PIDTYPE_PID].pid)) {
 			/* The thread running this VCPU changed. */
@@ -2574,6 +2574,7 @@ static long kvm_vcpu_ioctl(struct file *filp,
 			put_pid(oldpid);
 		}
 		r = kvm_arch_vcpu_ioctl_run(vcpu, vcpu->run);
+		vcpu_put(vcpu);
 		trace_kvm_userspace_exit(vcpu->run->exit_reason, r);
 		break;
 	}
@@ -2584,7 +2585,9 @@ static long kvm_vcpu_ioctl(struct file *filp,
 		kvm_regs = kzalloc(sizeof(struct kvm_regs), GFP_KERNEL);
 		if (!kvm_regs)
 			goto out;
+		vcpu_load(vcpu);
 		r = kvm_arch_vcpu_ioctl_get_regs(vcpu, kvm_regs);
+		vcpu_put(vcpu);
 		if (r)
 			goto out_free1;
 		r = -EFAULT;
@@ -2604,7 +2607,9 @@ static long kvm_vcpu_ioctl(struct file *filp,
 			r = PTR_ERR(kvm_regs);
 			goto out;
 		}
+		vcpu_load(vcpu);
 		r = kvm_arch_vcpu_ioctl_set_regs(vcpu, kvm_regs);
+		vcpu_put(vcpu);
 		kfree(kvm_regs);
 		break;
 	}
@@ -2613,7 +2618,9 @@ static long kvm_vcpu_ioctl(struct file *filp,
 		r = -ENOMEM;
 		if (!kvm_sregs)
 			goto out;
+		vcpu_load(vcpu);
 		r = kvm_arch_vcpu_ioctl_get_sregs(vcpu, kvm_sregs);
+		vcpu_put(vcpu);
 		if (r)
 			goto out;
 		r = -EFAULT;
@@ -2629,13 +2636,17 @@ static long kvm_vcpu_ioctl(struct file *filp,
 			kvm_sregs = NULL;
 			goto out;
 		}
+		vcpu_load(vcpu);
 		r = kvm_arch_vcpu_ioctl_set_sregs(vcpu, kvm_sregs);
+		vcpu_put(vcpu);
 		break;
 	}
 	case KVM_GET_MP_STATE: {
 		struct kvm_mp_state mp_state;
 
+		vcpu_load(vcpu);
 		r = kvm_arch_vcpu_ioctl_get_mpstate(vcpu, &mp_state);
+		vcpu_put(vcpu);
 		if (r)
 			goto out;
 		r = -EFAULT;
@@ -2650,7 +2661,9 @@ static long kvm_vcpu_ioctl(struct file *filp,
 		r = -EFAULT;
 		if (copy_from_user(&mp_state, argp, sizeof(mp_state)))
 			goto out;
+		vcpu_load(vcpu);
 		r = kvm_arch_vcpu_ioctl_set_mpstate(vcpu, &mp_state);
+		vcpu_put(vcpu);
 		break;
 	}
 	case KVM_TRANSLATE: {
@@ -2659,7 +2672,9 @@ static long kvm_vcpu_ioctl(struct file *filp,
 		r = -EFAULT;
 		if (copy_from_user(&tr, argp, sizeof(tr)))
 			goto out;
+		vcpu_load(vcpu);
 		r = kvm_arch_vcpu_ioctl_translate(vcpu, &tr);
+		vcpu_put(vcpu);
 		if (r)
 			goto out;
 		r = -EFAULT;
@@ -2674,7 +2689,9 @@ static long kvm_vcpu_ioctl(struct file *filp,
 		r = -EFAULT;
 		if (copy_from_user(&dbg, argp, sizeof(dbg)))
 			goto out;
+		vcpu_load(vcpu);
 		r = kvm_arch_vcpu_ioctl_set_guest_debug(vcpu, &dbg);
+		vcpu_put(vcpu);
 		break;
 	}
 	case KVM_SET_SIGNAL_MASK: {
@@ -2705,7 +2722,9 @@ static long kvm_vcpu_ioctl(struct file *filp,
 		r = -ENOMEM;
 		if (!fpu)
 			goto out;
+		vcpu_load(vcpu);
 		r = kvm_arch_vcpu_ioctl_get_fpu(vcpu, fpu);
+		vcpu_put(vcpu);
 		if (r)
 			goto out;
 		r = -EFAULT;
@@ -2721,14 +2740,17 @@ static long kvm_vcpu_ioctl(struct file *filp,
 			fpu = NULL;
 			goto out;
 		}
+		vcpu_load(vcpu);
 		r = kvm_arch_vcpu_ioctl_set_fpu(vcpu, fpu);
+		vcpu_put(vcpu);
 		break;
 	}
 	default:
+		vcpu_load(vcpu);
 		r = kvm_arch_vcpu_ioctl(filp, ioctl, arg);
+		vcpu_put(vcpu);
 	}
 out:
-	vcpu_put(vcpu);
 	mutex_unlock(&vcpu->mutex);
 	kfree(fpu);
 	kfree(kvm_sregs);