Commit 333c515d authored by Paolo Abeni's avatar Paolo Abeni
Browse files

vhost-net: allow configuring extended features 



Use the extended feature type for 'acked_features' and implement
two new ioctls operation allowing the user-space to set/query an
unbounded amount of features.

The actual number of processed features is limited by VIRTIO_FEATURES_MAX
and attempts to set features above such limit fail with
EOPNOTSUPP.

Note that: the legacy ioctls implicitly truncate the negotiated
features to the lower 64 bits range and the 'acked_backend_features'
field don't need conversion, as the only negotiated feature there
is in the low 64 bit range.

Acked-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 69b94615

drivers/vhost/net.c

+67 −20
Original line number Diff line number Diff line
@@ -69,12 +69,12 @@ MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;" 


#define VHOST_DMA_IS_DONE(len) ((__force u32)(len) >= (__force u32)VHOST_DMA_DONE_LEN)



enum {

	VHOST_NET_FEATURES = VHOST_FEATURES |

static const u64 vhost_net_features[VIRTIO_FEATURES_DWORDS] = {

	VHOST_FEATURES |

	(1ULL << VHOST_NET_F_VIRTIO_NET_HDR) |

	(1ULL << VIRTIO_NET_F_MRG_RXBUF) |

	(1ULL << VIRTIO_F_ACCESS_PLATFORM) |

			 (1ULL << VIRTIO_F_RING_RESET)

	(1ULL << VIRTIO_F_RING_RESET),

};



enum {
@@ -1614,16 +1614,17 @@ static long vhost_net_reset_owner(struct vhost_net *n) 
	return err;

}



static int vhost_net_set_features(struct vhost_net *n, u64 features)

static int vhost_net_set_features(struct vhost_net *n, const u64 *features)

{

	size_t vhost_hlen, sock_hlen, hdr_len;

	int i;



	hdr_len = (features & ((1ULL << VIRTIO_NET_F_MRG_RXBUF) |

			       (1ULL << VIRTIO_F_VERSION_1))) ?

	hdr_len = virtio_features_test_bit(features, VIRTIO_NET_F_MRG_RXBUF) ||

		  virtio_features_test_bit(features, VIRTIO_F_VERSION_1) ?

		  sizeof(struct virtio_net_hdr_mrg_rxbuf) :

		  sizeof(struct virtio_net_hdr);

	if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) {



	if (virtio_features_test_bit(features, VHOST_NET_F_VIRTIO_NET_HDR)) {

		/* vhost provides vnet_hdr */

		vhost_hlen = hdr_len;

		sock_hlen = 0;
@@ -1633,18 +1634,19 @@ static int vhost_net_set_features(struct vhost_net *n, u64 features) 
		sock_hlen = hdr_len;

	}

	mutex_lock(&n->dev.mutex);

	if ((features & (1 << VHOST_F_LOG_ALL)) &&

	if (virtio_features_test_bit(features, VHOST_F_LOG_ALL) &&

	    !vhost_log_access_ok(&n->dev))

		goto out_unlock;



	if ((features & (1ULL << VIRTIO_F_ACCESS_PLATFORM))) {

	if (virtio_features_test_bit(features, VIRTIO_F_ACCESS_PLATFORM)) {

		if (vhost_init_device_iotlb(&n->dev))

			goto out_unlock;

	}



	for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {

		mutex_lock(&n->vqs[i].vq.mutex);

		n->vqs[i].vq.acked_features = features;

		virtio_features_copy(n->vqs[i].vq.acked_features_array,

				     features);

		n->vqs[i].vhost_hlen = vhost_hlen;

		n->vqs[i].sock_hlen = sock_hlen;

		mutex_unlock(&n->vqs[i].vq.mutex);
@@ -1681,12 +1683,13 @@ static long vhost_net_set_owner(struct vhost_net *n) 
static long vhost_net_ioctl(struct file *f, unsigned int ioctl,

			    unsigned long arg)

{

	u64 all_features[VIRTIO_FEATURES_DWORDS];

	struct vhost_net *n = f->private_data;

	void __user *argp = (void __user *)arg;

	u64 __user *featurep = argp;

	struct vhost_vring_file backend;

	u64 features;

	int r;

	u64 features, count, copied;

	int r, i;



	switch (ioctl) {

	case VHOST_NET_SET_BACKEND:
@@ -1694,16 +1697,60 @@ static long vhost_net_ioctl(struct file *f, unsigned int ioctl, 
			return -EFAULT;

		return vhost_net_set_backend(n, backend.index, backend.fd);

	case VHOST_GET_FEATURES:

		features = VHOST_NET_FEATURES;

		features = vhost_net_features[0];

		if (copy_to_user(featurep, &features, sizeof features))

			return -EFAULT;

		return 0;

	case VHOST_SET_FEATURES:

		if (copy_from_user(&features, featurep, sizeof features))

			return -EFAULT;

		if (features & ~VHOST_NET_FEATURES)

		if (features & ~vhost_net_features[0])

			return -EOPNOTSUPP;



		virtio_features_from_u64(all_features, features);

		return vhost_net_set_features(n, all_features);

	case VHOST_GET_FEATURES_ARRAY:

		if (copy_from_user(&count, featurep, sizeof(count)))

			return -EFAULT;



		/* Copy the net features, up to the user-provided buffer size */

		argp += sizeof(u64);

		copied = min(count, VIRTIO_FEATURES_DWORDS);

		if (copy_to_user(argp, vhost_net_features,

				 copied * sizeof(u64)))

			return -EFAULT;



		/* Zero the trailing space provided by user-space, if any */

		if (clear_user(argp, size_mul(count - copied, sizeof(u64))))

			return -EFAULT;

		return 0;

	case VHOST_SET_FEATURES_ARRAY:

		if (copy_from_user(&count, featurep, sizeof(count)))

			return -EFAULT;



		virtio_features_zero(all_features);

		argp += sizeof(u64);

		copied = min(count, VIRTIO_FEATURES_DWORDS);

		if (copy_from_user(all_features, argp, copied * sizeof(u64)))

			return -EFAULT;



		/*

		 * Any feature specified by user-space above

		 * VIRTIO_FEATURES_MAX is not supported by definition.

		 */

		for (i = copied; i < count; ++i) {

			if (copy_from_user(&features, featurep + 1 + i,

					   sizeof(features)))

				return -EFAULT;

			if (features)

				return -EOPNOTSUPP;

		return vhost_net_set_features(n, features);

		}



		for (i = 0; i < VIRTIO_FEATURES_DWORDS; i++)

			if (all_features[i] & ~vhost_net_features[i])

				return -EOPNOTSUPP;



		return vhost_net_set_features(n, all_features);

	case VHOST_GET_BACKEND_FEATURES:

		features = VHOST_NET_BACKEND_FEATURES;

		if (copy_to_user(featurep, &features, sizeof(features)))

drivers/vhost/vhost.c

+1 −1
Original line number Diff line number Diff line
@@ -372,7 +372,7 @@ static void vhost_vq_reset(struct vhost_dev *dev, 
	vq->log_used = false;

	vq->log_addr = -1ull;

	vq->private_data = NULL;

	vq->acked_features = 0;

	virtio_features_zero(vq->acked_features_array);

	vq->acked_backend_features = 0;

	vq->log_base = NULL;

	vq->error_ctx = NULL;

drivers/vhost/vhost.h

+2 −2
Original line number Diff line number Diff line
@@ -133,7 +133,7 @@ struct vhost_virtqueue { 
	struct vhost_iotlb *umem;

	struct vhost_iotlb *iotlb;

	void *private_data;

	u64 acked_features;

	VIRTIO_DECLARE_FEATURES(acked_features);

	u64 acked_backend_features;

	/* Log write descriptors */

	void __user *log_base;
@@ -291,7 +291,7 @@ static inline void *vhost_vq_get_backend(struct vhost_virtqueue *vq) 


static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit)

{

	return vq->acked_features & (1ULL << bit);

	return virtio_features_test_bit(vq->acked_features_array, bit);

}



static inline bool vhost_backend_has_feature(struct vhost_virtqueue *vq, int bit)

include/uapi/linux/vhost.h

+7 −0
Original line number Diff line number Diff line
@@ -235,4 +235,11 @@ 
 */

#define VHOST_VDPA_GET_VRING_SIZE	_IOWR(VHOST_VIRTIO, 0x82,	\

					      struct vhost_vring_state)



/* Extended features manipulation */

#define VHOST_GET_FEATURES_ARRAY _IOR(VHOST_VIRTIO, 0x83, \

				       struct vhost_features_array)

#define VHOST_SET_FEATURES_ARRAY _IOW(VHOST_VIRTIO, 0x83, \

				       struct vhost_features_array)



#endif

include/uapi/linux/vhost_types.h

+5 −0
Original line number Diff line number Diff line
@@ -110,6 +110,11 @@ struct vhost_msg_v2 { 
	};

};



struct vhost_features_array {

	__u64 count; /* number of entries present in features array */

	__u64 features[] __counted_by(count);

};



struct vhost_memory_region {

	__u64 guest_phys_addr;

	__u64 memory_size; /* bytes */