From: Michael S. Tsirkin <mst@redhat.com>
Date: Wed, 29 Mar 2017 16:06:20 +0000 (+0300)
Subject: virtio: allow drivers to validate features
X-Git-Tag: Ubuntu-5.13.0-19.19~13704^2~9
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=404123c2db798027e852480ed9c4accef9f1d9e6;p=mirror_ubuntu-jammy-kernel.git

virtio: allow drivers to validate features

Some drivers can't support all features in all configurations.  At the
moment we blindly set FEATURES_OK and later FAILED.  Support this better
by adding a callback drivers can use to do some early checks.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---

diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index 400d70b69379..48230a5e12f2 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -232,6 +232,12 @@ static int virtio_dev_probe(struct device *_d)
 		if (device_features & (1ULL << i))
 			__virtio_set_bit(dev, i);
 
+	if (drv->validate) {
+		err = drv->validate(dev);
+		if (err)
+			goto err;
+	}
+
 	err = virtio_finalize_features(dev);
 	if (err)
 		goto err;
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 04b0d3f95043..7edfbdb55a99 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -167,6 +167,7 @@ struct virtio_driver {
 	unsigned int feature_table_size;
 	const unsigned int *feature_table_legacy;
 	unsigned int feature_table_size_legacy;
+	int (*validate)(struct virtio_device *dev);
 	int (*probe)(struct virtio_device *dev);
 	void (*scan)(struct virtio_device *dev);
 	void (*remove)(struct virtio_device *dev);