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: 079212f6877e ("vduse: add vq group asid support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20260202224835.559538-1-arnd@kernel.org>
diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 73d1d51..405d596 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -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)))
- break;
- } else {
- if (copy_from_user(&entry.v1, argp,
- sizeof(entry.v1)))
- break;
- }
+ if (copy_from_user(&entry, argp, _IOC_SIZE(cmd)))
+ 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;
diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
index 68b4287..361eea5 100644
--- a/include/uapi/linux/vduse.h
+++ b/include/uapi/linux/vduse.h
@@ -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;
};
/**
