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: Jason Wang Signed-off-by: Paolo Abeni --- v6 -> v7: - revert back to copy_from_user() to avoid a csky arch warning v5 -> v6: - deal with overflows with size_mul() v4 -> v5: - simpler VHOST_GET_FEATURES_ARRAY impl && fix - use get_user() when possible v3 -> v4: - use a single static (lower case) constant instead of enum and old def - simpler VHOST_GET_FEATURES_ARRAY impl - avoid using virtio_features_and_not v2 -> v3: - virtio_features_t -> u64[2] - add __counted_by annotation to vhost_features_array v1 -> v2: - change the ioctl to use an extensible API --- drivers/vhost/net.c | 87 ++++++++++++++++++++++++-------- drivers/vhost/vhost.c | 2 +- drivers/vhost/vhost.h | 4 +- include/uapi/linux/vhost.h | 7 +++ include/uapi/linux/vhost_types.h | 5 ++ 5 files changed, 82 insertions(+), 23 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 9dbd88eb9ff4..4aa2930382ad 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -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 | - (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) | - (1ULL << VIRTIO_NET_F_MRG_RXBUF) | - (1ULL << VIRTIO_F_ACCESS_PLATFORM) | - (1ULL << VIRTIO_F_RING_RESET) +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), }; enum { @@ -1606,16 +1606,17 @@ 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))) ? - sizeof(struct virtio_net_hdr_mrg_rxbuf) : - sizeof(struct virtio_net_hdr); - if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) { + 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 (virtio_features_test_bit(features, VHOST_NET_F_VIRTIO_NET_HDR)) { /* vhost provides vnet_hdr */ vhost_hlen = hdr_len; sock_hlen = 0; @@ -1625,18 +1626,19 @@ 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); @@ -1673,12 +1675,13 @@ 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: @@ -1686,16 +1689,60 @@ 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; - return vhost_net_set_features(n, features); + + 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; + } + + 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))) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 3a5ebb973dba..1094256a943c 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -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; diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index bb75a292d50c..d1aed35c4b07 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -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) diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h index d4b3e2ae1314..d6ad01fbb8d2 100644 --- a/include/uapi/linux/vhost.h +++ b/include/uapi/linux/vhost.h @@ -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 diff --git a/include/uapi/linux/vhost_types.h b/include/uapi/linux/vhost_types.h index d7656908f730..1c39cc5f5a31 100644 --- a/include/uapi/linux/vhost_types.h +++ b/include/uapi/linux/vhost_types.h @@ -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 */ -- 2.49.0