kernel/git/stable/linux.git/drivers/vhost/iotlb.c, branch master

vhost: fix inaccurate kdoc in iotlb helpers

2026-08-19T10:38:47+00:00

Correct missing "if" in the add_range_ctx return description, and align vhost_iotlb_alloc documentation with its NULL return on allocation failure. Signed-off-by: xiongweimin Signed-off-by: Michael S. Tsirkin Message-ID: <20260714024434.188302-1-15927021679@163.com>

vhost_iotlb: bound map allocation in add_range

2026-08-03T19:21:54+00:00

vhost_iotlb_add_range_ctx() only retires an old entry when the table has a non-zero limit, has exactly reached that limit and has VHOST_IOTLB_FLAG_RETIRE set. Non-retiring tables can keep allocating entries after reaching their configured limit. Existing vhost devices allocate their IOTLB with max_iotlb_entries from vhost.c, which defaults to 2048 and is tunable by module parameter. Use the caller-provided limit at the allocation point instead of adding a separate default in the common IOTLB helper, and reject non-positive values in vhost paths that can report an error. Other vhost IOTLB users should not create zero-limit tables when entries can be populated from userspace or guest-controlled requests. Add caller-side max_iotlb_entries parameters for mlx5 vDPA, VDUSE and vhost-vDPA. Reject non-positive VDUSE and vhost-vDPA values, and require at least two entries for vdpa_sim and mlx5 vDPA paths that install full-range mappings, since those mappings are split into two IOTLB entries. Handle full-range mappings in the common helper by checking that the IOTLB can hold both split entries before inserting the first half. This avoids returning an error after leaving a half mapping behind. When the table is full, keep the existing retire behavior for retiring tables and return -ENOSPC for non-retiring tables. Reuse the retired map node instead of freeing it and allocating a replacement, so a stream of IOTLB updates cannot keep forcing GFP_ATOMIC allocations after the table has reached its limit. If a zero-limit IOTLB still reaches the common helper, treat it as a configuration error and return -EINVAL. I found this bug myself, though the patch was written with AI assistance. Fixes: 0bbe30668d89 ("vhost: factor out IOTLB") Assisted-by: OpenAI-Codex:GPT-5 Signed-off-by: Linfeng Sun Message-ID: Signed-off-by: Michael S. Tsirkin

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

vhost_iotlb: split out IOTLB initialization

2022-05-31T16:44:28+00:00

This patch splits out IOTLB initialization to make sure it could be reused by external modules. Signed-off-by: Jason Wang Signed-off-by: Gautam Dawar Message-Id: <20220330180436.24644-9-gdawar@xilinx.com> Signed-off-by: Michael S. Tsirkin

vhost: handle error while adding split ranges to iotlb

2022-03-28T20:53:00+00:00

vhost_iotlb_add_range_ctx() handles the range [0, ULONG_MAX] by splitting it into two ranges and adding them separately. The return value of adding the first range to the iotlb is currently ignored. Check the return value and bail out in case of an error. Signed-off-by: Anirudh Rayabharam Link: https://lore.kernel.org/r/20220312141121.4981-1-mail@anirudhrb.com Signed-off-by: Michael S. Tsirkin Fixes: e2ae38cf3d91 ("vhost: fix hung thread due to erroneous iotlb entries") Reviewed-by: Stefano Garzarella

vhost: fix hung thread due to erroneous iotlb entries

2022-03-06T11:05:45+00:00

In vhost_iotlb_add_range_ctx(), range size can overflow to 0 when start is 0 and last is ULONG_MAX. One instance where it can happen is when userspace sends an IOTLB message with iova=size=uaddr=0 (vhost_process_iotlb_msg). So, an entry with size = 0, start = 0, last = ULONG_MAX ends up in the iotlb. Next time a packet is sent, iotlb_access_ok() loops indefinitely due to that erroneous entry. Call Trace: iotlb_access_ok+0x21b/0x3e0 drivers/vhost/vhost.c:1340 vq_meta_prefetch+0xbc/0x280 drivers/vhost/vhost.c:1366 vhost_transport_do_send_pkt+0xe0/0xfd0 drivers/vhost/vsock.c:104 vhost_worker+0x23d/0x3d0 drivers/vhost/vhost.c:372 kthread+0x2e9/0x3a0 kernel/kthread.c:377 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Reported by syzbot at: https://syzkaller.appspot.com/bug?extid=0abd373e2e50d704db87 To fix this, do two things: 1. Return -EINVAL in vhost_chr_write_iter() when userspace asks to map a range with size 0. 2. Fix vhost_iotlb_add_range_ctx() to handle the range [0, ULONG_MAX] by splitting it into two entries. Fixes: 0bbe30668d89e ("vhost: factor out IOTLB") Reported-by: syzbot+0abd373e2e50d704db87@syzkaller.appspotmail.com Tested-by: syzbot+0abd373e2e50d704db87@syzkaller.appspotmail.com Signed-off-by: Anirudh Rayabharam Link: https://lore.kernel.org/r/20220305095525.5145-1-mail@anirudhrb.com Signed-off-by: Michael S. Tsirkin

vhost-iotlb: Add an opaque pointer for vhost IOTLB

2021-09-06T11:20:57+00:00

Add an opaque pointer for vhost IOTLB. And introduce vhost_iotlb_add_range_ctx() to accept it. Suggested-by: Jason Wang Signed-off-by: Xie Yongji Acked-by: Jason Wang Link: https://lore.kernel.org/r/20210831103634.33-8-xieyongji@bytedance.com Signed-off-by: Michael S. Tsirkin

vhost-iotlb: fix vhost_iotlb_del_range() documentation

2021-07-03T08:50:50+00:00

Trivial change for the vhost_iotlb_del_range() documentation, fixing the function name in the comment block. Discovered with `make C=2 M=drivers/vhost`: ../drivers/vhost/iotlb.c:92: warning: expecting prototype for vring_iotlb_del_range(). Prototype was for vhost_iotlb_del_range() instead Signed-off-by: Stefano Garzarella Link: https://lore.kernel.org/r/20210504135444.158716-1-sgarzare@redhat.com Acked-by: Jason Wang Signed-off-by: Michael S. Tsirkin

vhost: Fix documentation

2020-09-24T09:54:36+00:00

Fix documentation to match actual function prototypes "end" used instead of "last". Fix that. Signed-off-by: Eli Cohen Link: https://lore.kernel.org/r/20200630052925.GA157062@mtl-vdi-166.wap.labs.mlnx Signed-off-by: Michael S. Tsirkin