Commit ebcff9da authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Michael S. Tsirkin
Browse files

vduse: avoid adding implicit padding 



The vduse_iova_range_v2 and vduse_iotlb_entry_v2 structures are both
defined in a way that adds implicit padding and is incompatible between
i386 and x86_64 userspace because of the different structure alignment
requirements. Building the header with -Wpadded shows these new warnings:

vduse.h:305:1: error: padding struct size to alignment boundary with 4 bytes [-Werror=padded]
vduse.h:374:1: error: padding struct size to alignment boundary with 4 bytes [-Werror=padded]

Change the amount of padding in these two structures to align them to
64 bit words and avoid those problems. Since the v1 vduse_iotlb_entry
already has an inconsistent size, do not attempt to reuse the structure
but rather list the members indiviudally, with a fixed amount of
padding.

Fixes: 079212f6 ("vduse: add vq group asid support")
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Message-Id: <20260202224835.559538-1-arnd@kernel.org>
parent 5145b277

drivers/vdpa/vdpa_user/vduse_dev.c

+14 −26
Original line number Diff line number Diff line
@@ -1301,7 +1301,7 @@ static int vduse_dev_iotlb_entry(struct vduse_dev *dev, 
	int r = -EINVAL;

	struct vhost_iotlb_map *map;



	if (entry->v1.start > entry->v1.last || entry->asid >= dev->nas)

	if (entry->start > entry->last || entry->asid >= dev->nas)

		return -EINVAL;



	asid = array_index_nospec(entry->asid, dev->nas);
@@ -1312,18 +1312,18 @@ static int vduse_dev_iotlb_entry(struct vduse_dev *dev, 


	spin_lock(&dev->as[asid].domain->iotlb_lock);

	map = vhost_iotlb_itree_first(dev->as[asid].domain->iotlb,

				      entry->v1.start, entry->v1.last);

				      entry->start, entry->last);

	if (map) {

		if (f) {

			const struct vdpa_map_file *map_file;



			map_file = (struct vdpa_map_file *)map->opaque;

			entry->v1.offset = map_file->offset;

			entry->offset = map_file->offset;

			*f = get_file(map_file->file);

		}

		entry->v1.start = map->start;

		entry->v1.last = map->last;

		entry->v1.perm = map->perm;

		entry->start = map->start;

		entry->last = map->last;

		entry->perm = map->perm;

		if (capability) {

			*capability = 0;
@@ -1363,14 +1363,8 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd, 
			break;



		ret = -EFAULT;

		if (cmd == VDUSE_IOTLB_GET_FD2) {

			if (copy_from_user(&entry, argp, sizeof(entry)))

		if (copy_from_user(&entry, argp, _IOC_SIZE(cmd)))

			break;

		} else {

			if (copy_from_user(&entry.v1, argp,

					   sizeof(entry.v1)))

				break;

		}



		ret = -EINVAL;

		if (!is_mem_zero((const char *)entry.reserved,
@@ -1385,19 +1379,13 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd, 
		if (!f)

			break;



		if (cmd == VDUSE_IOTLB_GET_FD2)

			ret = copy_to_user(argp, &entry,

					   sizeof(entry));

		else

			ret = copy_to_user(argp, &entry.v1,

					   sizeof(entry.v1));



		ret = copy_to_user(argp, &entry, _IOC_SIZE(cmd));

		if (ret) {

			ret = -EFAULT;

			fput(f);

			break;

		}

		ret = receive_fd(f, NULL, perm_to_file_flags(entry.v1.perm));

		ret = receive_fd(f, NULL, perm_to_file_flags(entry.perm));

		fput(f);

		break;

	}
@@ -1603,16 +1591,16 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd, 
		} else if (info.asid >= dev->nas)

			break;



		entry.v1.start = info.start;

		entry.v1.last = info.last;

		entry.start = info.start;

		entry.last = info.last;

		entry.asid = info.asid;

		ret = vduse_dev_iotlb_entry(dev, &entry, NULL,

					    &info.capability);

		if (ret < 0)

			break;



		info.start = entry.v1.start;

		info.last = entry.v1.last;

		info.start = entry.start;

		info.last = entry.last;

		info.asid = entry.asid;



		ret = -EFAULT;

include/uapi/linux/vduse.h

+7 −2
Original line number Diff line number Diff line
@@ -293,9 +293,13 @@ struct vduse_iova_info { 
 * Structure used by VDUSE_IOTLB_GET_FD2 ioctl to find an overlapped IOVA region.

 */

struct vduse_iotlb_entry_v2 {

	struct vduse_iotlb_entry v1;

	__u64 offset;

	__u64 start;

	__u64 last;

	__u8 perm;

	__u8 padding[7];

	__u32 asid;

	__u32 reserved[12];

	__u32 reserved[11];

};



/*
@@ -365,6 +369,7 @@ struct vduse_iova_range_v2 { 
	__u64 start;

	__u64 last;

	__u32 asid;

	__u32 padding;

};



/**