KVM: PPC: Move xics_debugfs_init out of create

chazy · rkrcmar · commit 023e9fddc361 · 2016-08-12T12:01:26.000+02:00
As we are about to hold the kvm-&gt;lock during the create operation on KVM
devices, we should move the call to xics_debugfs_init into its own
function, since holding a mutex over extended amounts of time might not
be a good idea.

Introduce an init operation on the kvm_device_ops struct which cannot
fail and call this, if configured, after the device has been created.

Signed-off-by: Christoffer Dall &lt;christoffer.dall@linaro.org&gt;
Reviewed-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Signed-off-by: Radim Krčmář &lt;rkrcmar@redhat.com&gt;
diff --git a/arch/powerpc/kvm/book3s_xics.c b/arch/powerpc/kvm/book3s_xics.c
@@ -1341,8 +1341,6 @@ static int kvmppc_xics_create(struct kvm_device *dev, u32 type)
 		return ret;
 	}
 
-	xics_debugfs_init(xics);
-
 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
 	if (cpu_has_feature(CPU_FTR_ARCH_206)) {
 		/* Enable real mode support */
@@ -1354,9 +1352,17 @@ static int kvmppc_xics_create(struct kvm_device *dev, u32 type)
 	return 0;
 }
 
+static void kvmppc_xics_init(struct kvm_device *dev)
+{
+	struct kvmppc_xics *xics = (struct kvmppc_xics *)dev->private;
+
+	xics_debugfs_init(xics);
+}
+
 struct kvm_device_ops kvm_xics_ops = {
 	.name = "kvm-xics",
 	.create = kvmppc_xics_create,
+	.init = kvmppc_xics_init,
 	.destroy = kvmppc_xics_free,
 	.set_attr = xics_set_attr,
 	.get_attr = xics_get_attr,
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
@@ -1115,6 +1115,12 @@ struct kvm_device_ops {
 	const char *name;
 	int (*create)(struct kvm_device *dev, u32 type);
 
+	/*
+	 * init is called after create if create is successful and is called
+	 * outside of holding kvm->lock.
+	 */
+	void (*init)(struct kvm_device *dev);
+
 	/*
 	 * Destroy is responsible for freeing dev.
 	 *
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
@@ -2838,6 +2838,9 @@ static int kvm_ioctl_create_device(struct kvm *kvm,
 		return ret;
 	}
 
+	if (ops->init)
+		ops->init(dev);
+
 	ret = anon_inode_getfd(ops->name, &kvm_device_fops, dev, O_RDWR | O_CLOEXEC);
 	if (ret < 0) {
 		ops->destroy(dev);

Original file line number	Diff line number	Diff line change
`@@ -2838,6 +2838,9 @@ static int kvm_ioctl_create_device(struct kvm *kvm,`
`2838`	`2838`	`return ret;`
`2839`	`2839`	`}`
`2840`	`2840`
	`2841`	`+ if (ops->init)`
	`2842`	`+ ops->init(dev);`
	`2843`	`+`
`2841`	`2844`	`ret = anon_inode_getfd(ops->name, &kvm_device_fops, dev, O_RDWR \| O_CLOEXEC);`
`2842`	`2845`	`if (ret < 0) {`
`2843`	`2846`	`ops->destroy(dev);`