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3 daysvhost-net: fix TX stall when vhost owns virtio-net headerEnrico Zanda1-3/+5
[ Upstream commit 3c0d10f233f19153f81fef685b5c6716776a5af3 ] When vhost owns the virtio-net header, i.e. when VHOST_NET_F_VIRTIO_NET_HDR is negotiated, sock_hlen is 0, meaning that no header will be forwarded to the TAP device. In the current vhost_net_build_xdp() implementation, when sock_hlen == 0, the gso pointer can point at the start of the Ethernet frame instead of a virtio-net header. This results in a wrong interpretation of the destination MAC address bytes as struct virtio_net_hdr fields. This can, for some MAC addresses, trigger -EINVAL and return early before the TX descriptor is completed, which can stall vhost-net TX. Before 97b2409f28e0, the gso pointer was set to the zeroed padding area, using it as a synthetic virtio-net header. Restore that behavior. Fixes: 97b2409f28e0 ("vhost-net: reduce one userspace copy when building XDP buff") Signed-off-by: Enrico Zanda <enrico.zanda@arm.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Link: https://patch.msgid.link/20260708152242.2268848-1-enrico.zanda@arm.com Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
13 daysvhost/net: complete zerocopy ubufs only onceQing Ming1-4/+11
[ Upstream commit 8f6898fe80794f2d7c3d38c1158c806e4074a1c4 ] vhost-net initializes one ubuf_info per outstanding zerocopy TX descriptor and hands it to the backend socket. The networking stack may then clone a zerocopy skb before all skb references are released. For example, batman-adv fragmentation reaches skb_split(), which calls skb_zerocopy_clone() and increments the same ubuf_info refcount. vhost_zerocopy_complete() currently treats every ubuf callback as a completed vhost descriptor. It dereferences ubuf->ctx, writes the descriptor completion state, and drops the vhost_net_ubuf_ref even when the callback only releases a cloned skb reference. A backend reset can therefore wait for and free the vhost_net_ubuf_ref while another cloned skb still carries the same ubuf_info. A later completion then dereferences the freed ubufs pointer. KASAN reports the stale completion as: BUG: KASAN: slab-use-after-free in vhost_zerocopy_complete+0x1d7/0x1f0 BUG: KASAN: slab-use-after-free in vhost_zerocopy_complete+0x101/0x1f0 vhost_zerocopy_complete skb_copy_ubufs __dev_forward_skb2 veth_xmit The freed object was allocated from vhost_net_ioctl() while setting the backend and freed through kfree_rcu()/kvfree_rcu_bulk after backend removal, while delayed skb completion still reached vhost_zerocopy_complete(). Honor the generic ubuf_info refcount before touching vhost state, and run the vhost descriptor completion only for the final ubuf reference. This matches the msg_zerocopy_complete() ownership rule for cloned zerocopy skbs. Fixes: bab632d69ee4 ("vhost: vhost TX zero-copy support") Signed-off-by: Qing Ming <a0yami@mailbox.org> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Message-ID: <20260601104300.197210-1-a0yami@mailbox.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
13 daysvhost/vdpa: validate virtqueue index in mmap and fault pathsQihang Tang1-7/+22
[ Upstream commit 929e4f044621c8cc30b612fb74e1410bef09e41b ] vhost_vdpa_mmap() and vhost_vdpa_fault() use vma->vm_pgoff as a virtqueue index for get_vq_notification(), but they do not validate that the index is smaller than v->nvqs. The ioctl path already performs both a bounds check and array_index_nospec(), but the mmap/fault path only checks that the index fits in u16. This allows an out-of-range queue index to reach driver-specific get_vq_notification() callbacks. Fix this by extracting a unified vhost_vdpa_get_vq_notification() helper that validates the queue index against v->nvqs and applies array_index_nospec() before calling the driver callback. Both the mmap and fault paths use this helper, and the bounds checking is consolidated into a single location. From source inspection, the most defensible impact is out-of-bounds access in the callback path, potentially leading to invalid PFN remaps and crash/DoS. Fixes: ddd89d0a059d ("vhost_vdpa: support doorbell mapping via mmap") Acked-by: Eugenio Pérez <eperezma@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Qihang Tang <q.h.hack.winter@gmail.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Message-ID: <20260508075821.92656-1-q.h.hack.winter@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
13 daysvhost: fix vhost_get_avail_idx for a non empty ringMichael S. Tsirkin1-4/+7
[ Upstream commit 09861858a68342f851f71c669ac0f69865c32151 ] vhost_get_avail_idx is supposed to report whether it has updated vq->avail_idx. Instead, it returns whether all entries have been consumed, which is usually the same. But not always - in drivers/vhost/net.c and when mergeable buffers have been enabled, the driver checks whether the combined entries are big enough to store an incoming packet. If not, the driver re-enables notifications with available entries still in the ring. The incorrect return value from vhost_get_avail_idx propagates through vhost_enable_notify and causes the host to livelock if the guest is not making progress, as vhost will immediately disable notifications and retry using the available entries. This goes back to commit d3bb267bbdcb ("vhost: cache avail index in vhost_enable_notify()") which changed vhost_enable_notify() to compare the freshly read avail index against vq->last_avail_idx instead of the previously cached vq->avail_idx. Commit 7ad472397667 ("vhost: move smp_rmb() into vhost_get_avail_idx()") then carried over the same comparison when refactoring vhost_enable_notify() to call the unified vhost_get_avail_idx(). The obvious fix is to make vhost_get_avail_idx do what the comment says it does and report whether new entries have been added. Reported-by: ShuangYu <shuangyu@yunyoo.cc> Fixes: d3bb267bbdcb ("vhost: cache avail index in vhost_enable_notify()") Cc: Stefan Hajnoczi <stefanha@redhat.com> Acked-by: Jason Wang <jasowang@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Message-Id: <559b04ae6ce52973c535dc47e461638b7f4c3d63.1772441455.git.mst@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-04-24Merge tag 'net-7.1-rc1' of ↵Linus Torvalds1-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net Pull networking fixes from Jakub Kicinski: "Including fixes from Netfilter. Steady stream of fixes. Last two weeks feel comparable to the two weeks before the merge window. Lots of AI-aided bug discovery. A newer big source is Sashiko/Gemini (Roman Gushchin's system), which points out issues in existing code during patch review (maybe 25% of fixes here likely originating from Sashiko). Nice thing is these are often fixed by the respective maintainers, not drive-bys. Current release - new code bugs: - kconfig: MDIO_PIC64HPSC should depend on ARCH_MICROCHIP Previous releases - regressions: - add async ndo_set_rx_mode and switch drivers which we promised to be called under the per-netdev mutex to it - dsa: remove duplicate netdev_lock_ops() for conduit ethtool ops - hv_sock: report EOF instead of -EIO for FIN - vsock/virtio: fix MSG_PEEK calculation on bytes to copy Previous releases - always broken: - ipv6: fix possible UAF in icmpv6_rcv() - icmp: validate reply type before using icmp_pointers - af_unix: drop all SCM attributes for SOCKMAP - netfilter: fix a number of bugs in the osf (OS fingerprinting) - eth: intel: fix timestamp interrupt configuration for E825C Misc: - bunch of data-race annotations" * tag 'net-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (148 commits) rxrpc: Fix error handling in rxgk_extract_token() rxrpc: Fix re-decryption of RESPONSE packets rxrpc: Fix rxrpc_input_call_event() to only unshare DATA packets rxrpc: Fix missing validation of ticket length in non-XDR key preparsing rxgk: Fix potential integer overflow in length check rxrpc: Fix conn-level packet handling to unshare RESPONSE packets rxrpc: Fix potential UAF after skb_unshare() failure rxrpc: Fix rxkad crypto unalignment handling rxrpc: Fix memory leaks in rxkad_verify_response() net: rds: fix MR cleanup on copy error m68k: mvme147: Make me the maintainer net: txgbe: fix firmware version check selftests/bpf: check epoll readiness during reuseport migration tcp: call sk_data_ready() after listener migration vhost_net: fix sleeping with preempt-disabled in vhost_net_busy_poll() ipv6: Cap TLV scan in ip6_tnl_parse_tlv_enc_lim tipc: fix double-free in tipc_buf_append() llc: Return -EINPROGRESS from llc_ui_connect() ipv4: icmp: validate reply type before using icmp_pointers selftests/net: packetdrill: cover RFC 5961 5.2 challenge ACK on both edges ...
2026-04-23vhost_net: fix sleeping with preempt-disabled in vhost_net_busy_poll()Kohei Enju1-2/+2
syzbot reported "sleeping function called from invalid context" in vhost_net_busy_poll(). Commit 030881372460 ("vhost_net: basic polling support") introduced a busy-poll loop and preempt_{disable,enable}() around it, where each iteration calls a sleepable function inside the loop. The purpose of disabling preemption was to keep local_clock()-based timeout accounting on a single CPU, rather than as a requirement of busy-poll itself: https://lore.kernel.org/1448435489-5949-4-git-send-email-jasowang@redhat.com From this perspective, migrate_disable() is sufficient here, so replace preempt_disable() with migrate_disable(), avoiding sleepable accesses from a preempt-disabled context. Fixes: 030881372460 ("vhost_net: basic polling support") Tested-by: syzbot+6985cb8e543ea90ba8ee@syzkaller.appspotmail.com Reported-by: syzbot+6985cb8e543ea90ba8ee@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/69e6a414.050a0220.24bfd3.002d.GAE@google.com/T/ Signed-off-by: Kohei Enju <kohei@enjuk.jp> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-04-21Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsiLinus Torvalds1-0/+2
Pull SCSI updates from James Bottomley: "Usual driver updates (ufs, lpfc, fnic, target, mpi3mr). The substantive core changes are adding a 'serial' sysfs attribute and getting sd to support > PAGE_SIZE sectors" * tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (98 commits) scsi: target: Don't validate ignored fields in PROUT PREEMPT scsi: qla2xxx: Use nr_cpu_ids instead of NR_CPUS for qp_cpu_map allocation scsi: ufs: core: Disable timestamp for Kioxia THGJFJT0E25BAIP scsi: mpi3mr: Fix typo scsi: sd: fix missing put_disk() when device_add(&disk_dev) fails scsi: libsas: Delete unused to_dom_device() and to_dev_attr() scsi: storvsc: Handle PERSISTENT_RESERVE_IN truncation for Hyper-V vFC scsi: iscsi_tcp: Remove unneeded selections of CRYPTO and CRYPTO_MD5 scsi: lpfc: Update lpfc version to 15.0.0.0 scsi: lpfc: Add PCI ID support for LPe42100 series adapters scsi: lpfc: Introduce 128G link speed selection and support scsi: lpfc: Check ASIC_ID register to aid diagnostics during failed fw updates scsi: lpfc: Update construction of SGL when XPSGL is enabled scsi: lpfc: Remove deprecated PBDE feature scsi: lpfc: Add REG_VFI mailbox cmd error handling scsi: lpfc: Log MCQE contents for mbox commands with no context scsi: lpfc: Select mailbox rq_create cmd version based on SLI4 if_type scsi: lpfc: Break out of IRQ affinity assignment when mask reaches nr_cpu_ids scsi: ufs: core: Make the header files self-contained scsi: ufs: core: Remove an include directive from ufshcd-crypto.h ...
2026-03-12vsock: add G2H fallback for CIDs not owned by H2G transportAlexander Graf1-0/+13
When no H2G transport is loaded, vsock currently routes all CIDs to the G2H transport (commit 65b422d9b61b ("vsock: forward all packets to the host when no H2G is registered"). Extend that existing behavior: when an H2G transport is loaded but does not claim a given CID, the connection falls back to G2H in the same way. This matters in environments like Nitro Enclaves, where an instance may run nested VMs via vhost-vsock (H2G) while also needing to reach sibling enclaves at higher CIDs through virtio-vsock-pci (G2H). With the old code, any CID > 2 was unconditionally routed to H2G when vhost was loaded, making those enclaves unreachable without setting VMADDR_FLAG_TO_HOST explicitly on every connect. Requiring every application to set VMADDR_FLAG_TO_HOST creates friction: tools like socat, iperf, and others would all need to learn about it. The flag was introduced 6 years ago and I am still not aware of any tool that supports it. Even if there was support, it would be cumbersome to use. The most natural experience is a single CID address space where H2G only wins for CIDs it actually owns, and everything else falls through to G2H, extending the behavior that already exists when H2G is absent. To give user space at least a hint that the kernel applied this logic, automatically set the VMADDR_FLAG_TO_HOST on the remote address so it can determine the path taken via getpeername(). Add a per-network namespace sysctl net.vsock.g2h_fallback (default 1). At 0 it forces strict routing: H2G always wins for CID > VMADDR_CID_HOST, or ENODEV if H2G is not loaded. Signed-off-by: Alexander Graf <graf@amazon.com> Tested-by: syzbot@syzkaller.appspotmail.com Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Link: https://patch.msgid.link/20260304230027.59857-1-graf@amazon.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-03-01scsi: vhost-scsi: Report direction completion supportMike Christie1-0/+1
This has vhost-scsi report that it supports direct completions. When using a worker task per queue or group of queues with fast backends then enabling direct completion and submissions increases performance 20-30% with workloads like: fio --filename=/dev/sdb --direct=1 --rw=randrw --bs=8K \ --ioengine=libaio --iodepth=128 --numjobs=$jobs As jobs matches and passes the number of vCPUs in the VM then the benefit increases. However, when using a single worker then queueing completions and submissions is best as the worker is busy handling mapping data and setting/tearing down commands. Signed-off-by: Mike Christie <michael.christie@oracle.com> Link: https://patch.msgid.link/20260222232946.7637-5-michael.christie@oracle.com Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2026-03-01scsi: target: Use driver completion preference by defaultMike Christie1-0/+1
This has us use the driver's completion preference by default. There is no behavior changes with this patch and we queue completion to LIO's completion workqueue by default. Signed-off-by: Mike Christie <michael.christie@oracle.com> Link: https://patch.msgid.link/20260222232946.7637-3-michael.christie@oracle.com Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2026-02-22Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL usesKees Cook1-4/+2
Conversion performed via this Coccinelle script: // SPDX-License-Identifier: GPL-2.0-only // Options: --include-headers-for-types --all-includes --include-headers --keep-comments virtual patch @gfp depends on patch && !(file in "tools") && !(file in "samples")@ identifier ALLOC = {kmalloc_obj,kmalloc_objs,kmalloc_flex, kzalloc_obj,kzalloc_objs,kzalloc_flex, kvmalloc_obj,kvmalloc_objs,kvmalloc_flex, kvzalloc_obj,kvzalloc_objs,kvzalloc_flex}; @@ ALLOC(... - , GFP_KERNEL ) $ make coccicheck MODE=patch COCCI=gfp.cocci Build and boot tested x86_64 with Fedora 42's GCC and Clang: Linux version 6.19.0+ (user@host) (gcc (GCC) 15.2.1 20260123 (Red Hat 15.2.1-7), GNU ld version 2.44-12.fc42) #1 SMP PREEMPT_DYNAMIC 1970-01-01 Linux version 6.19.0+ (user@host) (clang version 20.1.8 (Fedora 20.1.8-4.fc42), LLD 20.1.8) #1 SMP PREEMPT_DYNAMIC 1970-01-01 Signed-off-by: Kees Cook <kees@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-22Convert more 'alloc_obj' cases to default GFP_KERNEL argumentsLinus Torvalds3-8/+4
This converts some of the visually simpler cases that have been split over multiple lines. I only did the ones that are easy to verify the resulting diff by having just that final GFP_KERNEL argument on the next line. Somebody should probably do a proper coccinelle script for this, but for me the trivial script actually resulted in an assertion failure in the middle of the script. I probably had made it a bit _too_ trivial. So after fighting that far a while I decided to just do some of the syntactically simpler cases with variations of the previous 'sed' scripts. The more syntactically complex multi-line cases would mostly really want whitespace cleanup anyway. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-22Convert 'alloc_flex' family to use the new default GFP_KERNEL argumentLinus Torvalds1-1/+1
This is the exact same thing as the 'alloc_obj()' version, only much smaller because there are a lot fewer users of the *alloc_flex() interface. As with alloc_obj() version, this was done entirely with mindless brute force, using the same script, except using 'flex' in the pattern rather than 'objs*'. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-22Convert 'alloc_obj' family to use the new default GFP_KERNEL argumentLinus Torvalds7-25/+25
This was done entirely with mindless brute force, using git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' | xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/' to convert the new alloc_obj() users that had a simple GFP_KERNEL argument to just drop that argument. Note that due to the extreme simplicity of the scripting, any slightly more complex cases spread over multiple lines would not be triggered: they definitely exist, but this covers the vast bulk of the cases, and the resulting diff is also then easier to check automatically. For the same reason the 'flex' versions will be done as a separate conversion. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-21treewide: Replace kmalloc with kmalloc_obj for non-scalar typesKees Cook8-59/+49
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 <kees@kernel.org>
2026-02-13Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhostLinus Torvalds2-5/+8
Pull virtio updates from Michael Tsirkin: - in-order support in virtio core - multiple address space support in vduse - fixes, cleanups all over the place, notably dma alignment fixes for non-cache-coherent systems * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: (59 commits) vduse: avoid adding implicit padding vhost: fix caching attributes of MMIO regions by setting them explicitly vdpa/mlx5: update MAC address handling in mlx5_vdpa_set_attr() vdpa/mlx5: reuse common function for MAC address updates vdpa/mlx5: update mlx_features with driver state check crypto: virtio: Replace package id with numa node id crypto: virtio: Remove duplicated virtqueue_kick in virtio_crypto_skcipher_crypt_req crypto: virtio: Add spinlock protection with virtqueue notification Documentation: Add documentation for VDUSE Address Space IDs vduse: bump version number vduse: add vq group asid support vduse: merge tree search logic of IOTLB_GET_FD and IOTLB_GET_INFO ioctls vduse: take out allocations from vduse_dev_alloc_coherent vduse: remove unused vaddr parameter of vduse_domain_free_coherent vduse: refactor vdpa_dev_add for goto err handling vhost: forbid change vq groups ASID if DRIVER_OK is set vdpa: document set_group_asid thread safety vduse: return internal vq group struct as map token vduse: add vq group support vduse: add v1 API definition ...
2026-02-04vhost: fix caching attributes of MMIO regions by setting them explicitlyKommula Shiva Shankar1-0/+1
Explicitly set non-cached caching attributes for MMIO regions. Default write-back mode can cause CPU to cache device memory, causing invalid reads and unpredictable behavior. Invalid read and write issues were observed on ARM64 when mapping the notification area to userspace via mmap. Signed-off-by: Kommula Shiva Shankar <kshankar@marvell.com> Acked-by: Jason Wang <jasowang@redhat.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Message-Id: <20260102065703.656255-1-kshankar@marvell.com>
2026-01-28vhost: forbid change vq groups ASID if DRIVER_OK is setEugenio Pérez1-0/+2
Only vdpa_sim support it. Forbid this behaviour as there is no use for it right now, we can always enable it in the future with a feature flag. Acked-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Eugenio Pérez <eperezma@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Message-Id: <20260119143306.1818855-7-eperezma@redhat.com>
2026-01-28vhost: move vdpa group bound check to vhost_vdpaEugenio Pérez1-1/+1
Remove duplication by consolidating these here. This reduces the posibility of a parent driver missing them. While we're at it, fix a bug in vdpa_sim where a valid ASID can be assigned to a group equal to ngroups, causing an out of bound write. Cc: stable@vger.kernel.org Fixes: bda324fd037a ("vdpasim: control virtqueue support") Acked-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Eugenio Pérez <eperezma@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Message-Id: <20260119143306.1818855-2-eperezma@redhat.com>
2026-01-27vsock: add netns support to virtio transportsBobby Eshleman1-11/+27
Add netns support to loopback and vhost. Keep netns disabled for virtio-vsock, but add necessary changes to comply with common API updates. This is the patch in the series when vhost-vsock namespaces actually come online. Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com> Link: https://patch.msgid.link/20260121-vsock-vmtest-v16-3-2859a7512097@meta.com Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-01-27vsock: add netns to vsock coreBobby Eshleman1-2/+4
Add netns logic to vsock core. Additionally, modify transport hook prototypes to be used by later transport-specific patches (e.g., *_seqpacket_allow()). Namespaces are supported primarily by changing socket lookup functions (e.g., vsock_find_connected_socket()) to take into account the socket namespace and the namespace mode before considering a candidate socket a "match". This patch also introduces the sysctl /proc/sys/net/vsock/ns_mode to report the mode and /proc/sys/net/vsock/child_ns_mode to set the mode for new namespaces. Add netns functionality (initialization, passing to transports, procfs, etc...) to the af_vsock socket layer. Later patches that add netns support to transports depend on this patch. This patch changes the allocation of random ports for connectible vsocks in order to avoid leaking the random port range starting point to other namespaces. dgram_allow(), stream_allow(), and seqpacket_allow() callbacks are modified to take a vsk in order to perform logic on namespace modes. In future patches, the net will also be used for socket lookups in these functions. Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com> Link: https://patch.msgid.link/20260121-vsock-vmtest-v16-1-2859a7512097@meta.com Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-12-26vhost: use "checked" versions of get_user() and put_user()Jon Kohler1-4/+4
vhost_get_user and vhost_put_user leverage __get_user and __put_user, respectively, which were both added in 2016 by commit 6b1e6cc7855b ("vhost: new device IOTLB API"). In a heavy UDP transmit workload on a vhost-net backed tap device, these functions showed up as ~11.6% of samples in a flamegraph of the underlying vhost worker thread. Quoting Linus from [1]: Anyway, every single __get_user() call I looked at looked like historical garbage. [...] End result: I get the feeling that we should just do a global search-and-replace of the __get_user/ __put_user users, replace them with plain get_user/put_user instead, and then fix up any fallout (eg the coco code). Switch to plain get_user/put_user in vhost, which results in a slight throughput speedup. get_user now about ~8.4% of samples in flamegraph. Basic iperf3 test on a Intel 5416S CPU with Ubuntu 25.10 guest: TX: taskset -c 2 iperf3 -c <rx_ip> -t 60 -p 5200 -b 0 -u -i 5 RX: taskset -c 2 iperf3 -s -p 5200 -D Before: 6.08 Gbits/sec After: 6.32 Gbits/sec As to what drives the speedup, Sean's patch [2] explains: Use the normal, checked versions for get_user() and put_user() instead of the double-underscore versions that omit range checks, as the checked versions are actually measurably faster on modern CPUs (12%+ on Intel, 25%+ on AMD). The performance hit on the unchecked versions is almost entirely due to the added LFENCE on CPUs where LFENCE is serializing (which is effectively all modern CPUs), which was added by commit 304ec1b05031 ("x86/uaccess: Use __uaccess_begin_nospec() and uaccess_try_nospec"). The small optimizations done by commit b19b74bc99b1 ("x86/mm: Rework address range check in get_user() and put_user()") likely shave a few cycles off, but the bulk of the extra latency comes from the LFENCE. [1] https://lore.kernel.org/all/CAHk-=wiJiDSPZJTV7z3Q-u4DfLgQTNWqUqqrwSBHp0+Dh016FA@mail.gmail.com/ [2] https://lore.kernel.org/all/20251106210206.221558-1-seanjc@google.com/ Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Sean Christopherson <seanjc@google.com> Signed-off-by: Jon Kohler <jon@nutanix.com> Message-Id: <20251113005529.2494066-1-jon@nutanix.com> Acked-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2025-12-24vhost/vsock: improve RCU read sections around vhost_vsock_get()Stefano Garzarella1-4/+11
vhost_vsock_get() uses hash_for_each_possible_rcu() to find the `vhost_vsock` associated with the `guest_cid`. hash_for_each_possible_rcu() should only be called within an RCU read section, as mentioned in the following comment in include/linux/rculist.h: /** * hlist_for_each_entry_rcu - iterate over rcu list of given type * @pos: the type * to use as a loop cursor. * @head: the head for your list. * @member: the name of the hlist_node within the struct. * @cond: optional lockdep expression if called from non-RCU protection. * * This list-traversal primitive may safely run concurrently with * the _rcu list-mutation primitives such as hlist_add_head_rcu() * as long as the traversal is guarded by rcu_read_lock(). */ Currently, all calls to vhost_vsock_get() are between rcu_read_lock() and rcu_read_unlock() except for calls in vhost_vsock_set_cid() and vhost_vsock_reset_orphans(). In both cases, the current code is safe, but we can make improvements to make it more robust. About vhost_vsock_set_cid(), when building the kernel with CONFIG_PROVE_RCU_LIST enabled, we get the following RCU warning when the user space issues `ioctl(dev, VHOST_VSOCK_SET_GUEST_CID, ...)` : WARNING: suspicious RCU usage 6.18.0-rc7 #62 Not tainted ----------------------------- drivers/vhost/vsock.c:74 RCU-list traversed in non-reader section!! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by rpc-libvirtd/3443: #0: ffffffffc05032a8 (vhost_vsock_mutex){+.+.}-{4:4}, at: vhost_vsock_dev_ioctl+0x2ff/0x530 [vhost_vsock] stack backtrace: CPU: 2 UID: 0 PID: 3443 Comm: rpc-libvirtd Not tainted 6.18.0-rc7 #62 PREEMPT(none) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-7.fc42 06/10/2025 Call Trace: <TASK> dump_stack_lvl+0x75/0xb0 dump_stack+0x14/0x1a lockdep_rcu_suspicious.cold+0x4e/0x97 vhost_vsock_get+0x8f/0xa0 [vhost_vsock] vhost_vsock_dev_ioctl+0x307/0x530 [vhost_vsock] __x64_sys_ioctl+0x4f2/0xa00 x64_sys_call+0xed0/0x1da0 do_syscall_64+0x73/0xfa0 entry_SYSCALL_64_after_hwframe+0x76/0x7e ... </TASK> This is not a real problem, because the vhost_vsock_get() caller, i.e. vhost_vsock_set_cid(), holds the `vhost_vsock_mutex` used by the hash table writers. Anyway, to prevent that warning, add lockdep_is_held() condition to hash_for_each_possible_rcu() to verify that either the caller is in an RCU read section or `vhost_vsock_mutex` is held when CONFIG_PROVE_RCU_LIST is enabled; and also clarify the comment for vhost_vsock_get() to better describe the locking requirements and the scope of the returned pointer validity. About vhost_vsock_reset_orphans(), currently this function is only called via vsock_for_each_connected_socket(), which holds the `vsock_table_lock` spinlock (which is also an RCU read-side critical section). However, add an explicit RCU read lock there to make the code more robust and explicit about the RCU requirements, and to prevent issues if the calling context changes in the future or if vhost_vsock_reset_orphans() is called from other contexts. Fixes: 834e772c8db0 ("vhost/vsock: fix use-after-free in network stack callers") Cc: stefanha@redhat.com Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20251126133826.142496-1-sgarzare@redhat.com> Message-ID: <20251126210313.GA499503@fedora> Acked-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2025-12-05Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhostLinus Torvalds6-32/+72
Pull virtio updates from Michael Tsirkin: "Just a bunch of fixes and cleanups, mostly very simple. Several features were merged through net-next this time around" * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: virtio_pci: drop kernel.h vhost: switch to arrays of feature bits vhost/test: add test specific macro for features virtio: clean up features qword/dword terms vduse: add WQ_PERCPU to alloc_workqueue users virtio_balloon: add WQ_PERCPU to alloc_workqueue users vdpa/pds: use %pe for ERR_PTR() in event handler registration vhost: Fix kthread worker cgroup failure handling virtio: vdpa: Fix reference count leak in octep_sriov_enable() vdpa/mlx5: Fix incorrect error code reporting in query_virtqueues virtio: fix map ops comment virtio: fix virtqueue_set_affinity() docs virtio: standardize Returns documentation style virtio: fix grammar in virtio_map_ops docs virtio: fix grammar in virtio_queue_info docs virtio: fix whitespace in virtio_config_ops virtio: fix typo in virtio_device_ready() comment virtio: fix kernel-doc for mapping/free_coherent functions virtio_vdpa: fix misleading return in void function
2025-12-01vhost: switch to arrays of feature bitsMichael S. Tsirkin5-25/+61
The current interface where caller has to know in which 64 bit chunk each bit is, is inelegant and fragile. Let's simply use arrays of bits. By using unroll macros text size grows only slightly. Message-ID: <637e182e139980e5930d50b928ba5ac072d628a9.1764225384.git.mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2025-11-27vhost/test: add test specific macro for featuresMichael S. Tsirkin1-2/+4
test just uses vhost features with no change, but people tend to copy/paste code, so let's add our own define. Message-ID: <23ca04512a800ee8b3594482492e536020931340.1764225384.git.mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2025-11-27virtio: clean up features qword/dword termsMichael S. Tsirkin1-6/+6
virtio pci uses word to mean "16 bits". mmio uses it to mean "32 bits". To avoid confusion, let's avoid the term in core virtio altogether. Just say U64 to mean "64 bit". Fixes: e7d4c1c5a546 ("virtio: introduce extended features") Cc: Paolo Abeni <pabeni@redhat.com> Acked-by: Jason Wang <jasowang@redhat.com> Message-ID: <ad53b7b6be87fc524f45abaeca0bb05fb3633397.1764225384.git.mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2025-11-27vhost: Fix kthread worker cgroup failure handlingMike Christie1-1/+3
If we fail to attach to a cgroup we are leaking the id. This adds a new goto to free the id. Fixes: 7d9896e9f6d0 ("vhost: Reintroduce kthread API and add mode selection") Signed-off-by: Mike Christie <michael.christie@oracle.com> Acked-by: Jason Wang <jasowang@redhat.com> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Message-Id: <20251101194358.13605-1-michael.christie@oracle.com>
2025-11-27vhost: rewind next_avail_head while discarding descriptorsJason Wang3-36/+103
When discarding descriptors with IN_ORDER, we should rewind next_avail_head otherwise it would run out of sync with last_avail_idx. This would cause driver to report "id X is not a head". Fixing this by returning the number of descriptors that is used for each buffer via vhost_get_vq_desc_n() so caller can use the value while discarding descriptors. Fixes: 67a873df0c41 ("vhost: basic in order support") Cc: stable@vger.kernel.org Signed-off-by: Jason Wang <jasowang@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Link: https://patch.msgid.link/20251120022950.10117-1-jasowang@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-01vdpa: support virtio_mapJason Wang1-2/+4
Virtio core switches from DMA device to virtio_map, let's do that as well for vDPA. Signed-off-by: Jason Wang <jasowang@redhat.com> Message-Id: <20250821064641.5025-8-jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Tested-by: Lei Yang <leiyang@redhat.com> Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
2025-10-01vhost: vringh: Fix copy_to_iter return value checkMichael S. Tsirkin1-3/+4
The return value of copy_to_iter can't be negative, check whether the copied length is equal to the requested length instead of checking for negative values. Fixes: 309bba39c945 ("vringh: iterate on iotlb_translate to handle large translations") Cc: "Stefano Garzarella" <sgarzare@redhat.com> Cc: zhang jiao <zhangjiao2@cmss.chinamobile.com> Link: https://lore.kernel.org/all/20250910091739.2999-1-zhangjiao2@cmss.chinamobile.com Message-ID: <cd637504a6e3967954a9e80fc1b75e8c0978087b.1758723310.git.mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2025-10-01vhost: vringh: Modify the return value checkzhang jiao1-3/+4
The return value of copy_from_iter and copy_to_iter can't be negative, check whether the copied lengths are equal. Fixes: 309bba39c945 ("vringh: iterate on iotlb_translate to handle large translations") Cc: "Stefano Garzarella" <sgarzare@redhat.com> Signed-off-by: zhang jiao <zhangjiao2@cmss.chinamobile.com> Message-Id: <20250910091739.2999-1-zhangjiao2@cmss.chinamobile.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2025-09-19vhost-net: flush batched before enabling notificationsJason Wang1-0/+5
Commit 8c2e6b26ffe2 ("vhost/net: Defer TX queue re-enable until after sendmsg") tries to defer the notification enabling by moving the logic out of the loop after the vhost_tx_batch() when nothing new is spotted. This caused unexpected side effects as the new logic is reused for several other error conditions. A previous patch reverted 8c2e6b26ffe2. Now, bring the performance back up by flushing batched buffers before enabling notifications. Reported-by: Jon Kohler <jon@nutanix.com> Cc: stable@vger.kernel.org Fixes: 8c2e6b26ffe2 ("vhost/net: Defer TX queue re-enable until after sendmsg") Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Message-Id: <20250917063045.2042-3-jasowang@redhat.com>
2025-09-19Revert "vhost/net: Defer TX queue re-enable until after sendmsg"Michael S. Tsirkin1-21/+9
This reverts commit 8c2e6b26ffe243be1e78f5a4bfb1a857d6e6f6d6. It tries to defer the notification enabling by moving the logic out of the loop after the vhost_tx_batch() when nothing new is spotted. This will bring side effects as the new logic would be reused for several other error conditions. One example is the IOTLB: when there's an IOTLB miss, get_tx_bufs() might return -EAGAIN and exit the loop and see there's still available buffers, so it will queue the tx work again until userspace feed the IOTLB entry correctly. This will slowdown the tx processing and trigger the TX watchdog in the guest as reported in https://lkml.org/lkml/2025/9/10/1596. To fix, revert the change. A follow up patch will bring the performance back in a safe way. Reported-by: Jon Kohler <jon@nutanix.com> Cc: stable@vger.kernel.org Fixes: 8c2e6b26ffe2 ("vhost/net: Defer TX queue re-enable until after sendmsg") Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Message-Id: <20250917063045.2042-2-jasowang@redhat.com>
2025-09-19vhost-net: unbreak busy pollingJason Wang1-3/+4
Commit 67a873df0c41 ("vhost: basic in order support") pass the number of used elem to vhost_net_rx_peek_head_len() to make sure it can signal the used correctly before trying to do busy polling. But it forgets to clear the count, this would cause the count run out of sync with handle_rx() and break the busy polling. Fixing this by passing the pointer of the count and clearing it after the signaling the used. Acked-by: Michael S. Tsirkin <mst@redhat.com> Cc: stable@vger.kernel.org Fixes: 67a873df0c41 ("vhost: basic in order support") Signed-off-by: Jason Wang <jasowang@redhat.com> Message-Id: <20250917063045.2042-1-jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2025-09-16vhost-scsi: fix argument order in tport allocation error messageAlok Tiwari1-1/+1
The error log in vhost_scsi_make_tport() prints the arguments in the wrong order, producing confusing output. For example, when creating a target with a name in WWNN format such as "fc.port1234", the log looks like: Emulated fc.port1234 Address: FCP, exceeds max: 64 Instead, the message should report the emulated protocol type first, followed by the configfs name as: Emulated FCP Address: fc.port1234, exceeds max: 64 Fix the argument order so the error log is consistent and clear. Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com> Message-Id: <20250913154106.3995856-1-alok.a.tiwari@oracle.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2025-08-26vhost/net: Protect ubufs with rcu read lock in vhost_net_ubuf_put()Nikolay Kuratov1-2/+7
When operating on struct vhost_net_ubuf_ref, the following execution sequence is theoretically possible: CPU0 is finalizing DMA operation CPU1 is doing VHOST_NET_SET_BACKEND // ubufs->refcount == 2 vhost_net_ubuf_put() vhost_net_ubuf_put_wait_and_free(oldubufs) vhost_net_ubuf_put_and_wait() vhost_net_ubuf_put() int r = atomic_sub_return(1, &ubufs->refcount); // r = 1 int r = atomic_sub_return(1, &ubufs->refcount); // r = 0 wait_event(ubufs->wait, !atomic_read(&ubufs->refcount)); // no wait occurs here because condition is already true kfree(ubufs); if (unlikely(!r)) wake_up(&ubufs->wait); // use-after-free This leads to use-after-free on ubufs access. This happens because CPU1 skips waiting for wake_up() when refcount is already zero. To prevent that use a read-side RCU critical section in vhost_net_ubuf_put(), as suggested by Hillf Danton. For this lock to take effect, free ubufs with kfree_rcu(). Cc: stable@vger.kernel.org Fixes: 0ad8b480d6ee9 ("vhost: fix ref cnt checking deadlock") Reported-by: Andrey Ryabinin <arbn@yandex-team.com> Suggested-by: Hillf Danton <hdanton@sina.com> Signed-off-by: Nikolay Kuratov <kniv@yandex-team.ru> Message-Id: <20250805130917.727332-1-kniv@yandex-team.ru> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2025-08-05vhost: initialize vq->nheads properlyJason Wang1-0/+1
Commit 7918bb2d19c9 ("vhost: basic in order support") introduces vq->nheads to store the number of batched used buffers per used elem but it forgets to initialize the vq->nheads to NULL in vhost_dev_init() this will cause kfree() that would try to free it without be allocated if SET_OWNER is not called. Reported-by: JAEHOON KIM <jhkim@linux.ibm.com> Reported-by: Breno Leitao <leitao@debian.org> Fixes: 45347e79b544 ("vhost: basic in order support") Signed-off-by: Jason Wang <jasowang@redhat.com> Message-Id: <20250729073916.80647-1-jasowang@redhat.com> Reviewed-by: Dawid Osuchowski <dawid.osuchowski@linux.intel.com> Tested-by: Breno Leitao <leitao@debian.org> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Tested-by: Jaehoon Kim <jhkim@linux.ibm.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2025-08-02Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhostLinus Torvalds7-209/+461
Pull virtio updates from Michael Tsirkin: - vhost can now support legacy threading if enabled in Kconfig - vsock memory allocation strategies for large buffers have been improved, reducing pressure on kmalloc - vhost now supports the in-order feature. guest bits missed the merge window. - fixes, cleanups all over the place * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: (30 commits) vsock/virtio: Allocate nonlinear SKBs for handling large transmit buffers vsock/virtio: Rename virtio_vsock_skb_rx_put() vhost/vsock: Allocate nonlinear SKBs for handling large receive buffers vsock/virtio: Move SKB allocation lower-bound check to callers vsock/virtio: Rename virtio_vsock_alloc_skb() vsock/virtio: Resize receive buffers so that each SKB fits in a 4K page vsock/virtio: Move length check to callers of virtio_vsock_skb_rx_put() vsock/virtio: Validate length in packet header before skb_put() vhost/vsock: Avoid allocating arbitrarily-sized SKBs vhost_net: basic in_order support vhost: basic in order support vhost: fail early when __vhost_add_used() fails vhost: Reintroduce kthread API and add mode selection vdpa: Fix IDR memory leak in VDUSE module exit vdpa/mlx5: Fix release of uninitialized resources on error path vhost-scsi: Fix check for inline_sg_cnt exceeding preallocated limit virtio: virtio_dma_buf: fix missing parameter documentation vhost: Fix typos vhost: vringh: Remove unused functions vhost: vringh: Remove unused iotlb functions ...
2025-08-01vsock/virtio: Rename virtio_vsock_skb_rx_put()Will Deacon1-1/+1
In preparation for using virtio_vsock_skb_rx_put() when populating SKBs on the vsock TX path, rename virtio_vsock_skb_rx_put() to virtio_vsock_skb_put(). No functional change. Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Will Deacon <will@kernel.org> Message-Id: <20250717090116.11987-9-will@kernel.org> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2025-08-01vhost/vsock: Allocate nonlinear SKBs for handling large receive buffersWill Deacon1-5/+3
When receiving a packet from a guest, vhost_vsock_handle_tx_kick() calls vhost_vsock_alloc_linear_skb() to allocate and fill an SKB with the receive data. Unfortunately, these are always linear allocations and can therefore result in significant pressure on kmalloc() considering that the maximum packet size (VIRTIO_VSOCK_MAX_PKT_BUF_SIZE + VIRTIO_VSOCK_SKB_HEADROOM) is a little over 64KiB, resulting in a 128KiB allocation for each packet. Rework the vsock SKB allocation so that, for sizes with page order greater than PAGE_ALLOC_COSTLY_ORDER, a nonlinear SKB is allocated instead with the packet header in the SKB and the receive data in the fragments. Finally, add a debug warning if virtio_vsock_skb_rx_put() is ever called on an SKB with a non-zero length, as this would be destructive for the nonlinear case. Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Will Deacon <will@kernel.org> Message-Id: <20250717090116.11987-8-will@kernel.org> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2025-08-01vsock/virtio: Move SKB allocation lower-bound check to callersWill Deacon1-1/+2
virtio_vsock_alloc_linear_skb() checks that the requested size is at least big enough for the packet header (VIRTIO_VSOCK_SKB_HEADROOM). Of the three callers of virtio_vsock_alloc_linear_skb(), only vhost_vsock_alloc_skb() can potentially pass a packet smaller than the header size and, as it already has a check against the maximum packet size, extend its bounds checking to consider the minimum packet size and remove the check from virtio_vsock_alloc_linear_skb(). Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Will Deacon <will@kernel.org> Message-Id: <20250717090116.11987-7-will@kernel.org> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2025-08-01vsock/virtio: Rename virtio_vsock_alloc_skb()Will Deacon1-1/+1
In preparation for nonlinear allocations for large SKBs, rename virtio_vsock_alloc_skb() to virtio_vsock_alloc_linear_skb() to indicate that it returns linear SKBs unconditionally and switch all callers over to this new interface for now. No functional change. Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Will Deacon <will@kernel.org> Message-Id: <20250717090116.11987-6-will@kernel.org> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2025-08-01vsock/virtio: Move length check to callers of virtio_vsock_skb_rx_put()Will Deacon1-1/+1
virtio_vsock_skb_rx_put() only calls skb_put() if the length in the packet header is not zero even though skb_put() handles this case gracefully. Remove the functionally redundant check from virtio_vsock_skb_rx_put() and, on the assumption that this is a worthwhile optimisation for handling credit messages, augment the existing length checks in virtio_transport_rx_work() to elide the call for zero-length payloads. Since the callers all have the length, extend virtio_vsock_skb_rx_put() to take it as an additional parameter rather than fish it back out of the packet header. Note that the vhost code already has similar logic in vhost_vsock_alloc_skb(). Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Will Deacon <will@kernel.org> Message-Id: <20250717090116.11987-4-will@kernel.org> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2025-08-01vhost/vsock: Avoid allocating arbitrarily-sized SKBsWill Deacon1-2/+4
vhost_vsock_alloc_skb() returns NULL for packets advertising a length larger than VIRTIO_VSOCK_MAX_PKT_BUF_SIZE in the packet header. However, this is only checked once the SKB has been allocated and, if the length in the packet header is zero, the SKB may not be freed immediately. Hoist the size check before the SKB allocation so that an iovec larger than VIRTIO_VSOCK_MAX_PKT_BUF_SIZE + the header size is rejected outright. The subsequent check on the length field in the header can then simply check that the allocated SKB is indeed large enough to hold the packet. Cc: <stable@vger.kernel.org> Fixes: 71dc9ec9ac7d ("virtio/vsock: replace virtio_vsock_pkt with sk_buff") Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Will Deacon <will@kernel.org> Message-Id: <20250717090116.11987-2-will@kernel.org> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2025-08-01vhost_net: basic in_order supportJason Wang1-25/+61
This patch introduces basic in-order support for vhost-net. By recording the number of batched buffers in an array when calling `vhost_add_used_and_signal_n()`, we can reduce the number of userspace accesses. Note that the vhost-net batching logic is kept as we still count the number of buffers there. Testing Results: With testpmd: - TX: txonly mode + vhost_net with XDP_DROP on TAP shows a 17.5% improvement, from 4.75 Mpps to 5.35 Mpps. - RX: No obvious improvements were observed. With virtio-ring in-order experimental code in the guest: - TX: pktgen in the guest + XDP_DROP on TAP shows a 19% improvement, from 5.2 Mpps to 6.2 Mpps. - RX: pktgen on TAP with vhost_net + XDP_DROP in the guest achieves a 6.1% improvement, from 3.47 Mpps to 3.61 Mpps. Acked-by: Jonah Palmer <jonah.palmer@oracle.com> Acked-by: Eugenio Pérez <eperezma@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com> Message-Id: <20250714084755.11921-4-jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Tested-by: Lei Yang <leiyang@redhat.com>
2025-08-01vhost: basic in order supportJason Wang3-25/+109
This patch adds basic in order support for vhost. Two optimizations are implemented in this patch: 1) Since driver uses descriptor in order, vhost can deduce the next avail ring head by counting the number of descriptors that has been used in next_avail_head. This eliminate the need to access the available ring in vhost. 2) vhost_add_used_and_singal_n() is extended to accept the number of batched buffers per used elem. While this increases the times of userspace memory access but it helps to reduce the chance of used ring access of both the driver and vhost. Vhost-net will be the first user for this. Acked-by: Jonah Palmer <jonah.palmer@oracle.com> Signed-off-by: Jason Wang <jasowang@redhat.com> Message-Id: <20250714084755.11921-3-jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Tested-by: Lei Yang <leiyang@redhat.com>
2025-08-01vhost: fail early when __vhost_add_used() failsJason Wang1-0/+3
This patch fails vhost_add_used_n() early when __vhost_add_used() fails to make sure used idx is not updated with stale used ring information. Reported-by: Eugenio Pérez <eperezma@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com> Message-Id: <20250714084755.11921-2-jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Tested-by: Lei Yang <leiyang@redhat.com>
2025-08-01vhost: Reintroduce kthread API and add mode selectionCindy Lu3-18/+266
Since commit 6e890c5d5021 ("vhost: use vhost_tasks for worker threads"), the vhost uses vhost_task and operates as a child of the owner thread. This is required for correct CPU usage accounting, especially when using containers. However, this change has caused confusion for some legacy userspace applications, and we didn't notice until it's too late. Unfortunately, it's too late to revert - we now have userspace depending both on old and new behaviour :( To address the issue, reintroduce kthread mode for vhost workers and provide a configuration to select between kthread and task worker. - Add 'fork_owner' parameter to vhost_dev to let users select kthread or task mode. Default mode is task mode(VHOST_FORK_OWNER_TASK). - Reintroduce kthread mode support: * Bring back the original vhost_worker() implementation, and renamed to vhost_run_work_kthread_list(). * Add cgroup support for the kthread * Introduce struct vhost_worker_ops: - Encapsulates create / stop / wake‑up callbacks. - vhost_worker_create() selects the proper ops according to inherit_owner. - Userspace configuration interface: * New IOCTLs: - VHOST_SET_FORK_FROM_OWNER lets userspace select task mode (VHOST_FORK_OWNER_TASK) or kthread mode (VHOST_FORK_OWNER_KTHREAD) - VHOST_GET_FORK_FROM_OWNER reads the current worker mode * Expose module parameter 'fork_from_owner_default' to allow system administrators to configure the default mode for vhost workers * Kconfig option CONFIG_VHOST_ENABLE_FORK_OWNER_CONTROL controls whether these IOCTLs and the parameter are available - The VHOST_NEW_WORKER functionality requires fork_owner to be set to true, with validation added to ensure proper configuration This partially reverts or improves upon: commit 6e890c5d5021 ("vhost: use vhost_tasks for worker threads") commit 1cdaafa1b8b4 ("vhost: replace single worker pointer with xarray") Fixes: 6e890c5d5021 ("vhost: use vhost_tasks for worker threads"), Signed-off-by: Cindy Lu <lulu@redhat.com> Message-Id: <20250714071333.59794-2-lulu@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Jason Wang <jasowang@redhat.com> Tested-by: Lei Yang <leiyang@redhat.com>
2025-08-01vhost-scsi: Fix check for inline_sg_cnt exceeding preallocated limitAlok Tiwari1-1/+1
The condition comparing ret to VHOST_SCSI_PREALLOC_SGLS was incorrect, as ret holds the result of kstrtouint() (typically 0 on success), not the parsed value. Update the check to use cnt, which contains the actual user-provided value. prevents silently accepting values exceeding the maximum inline_sg_cnt. Fixes: bca939d5bcd0 ("vhost-scsi: Dynamically allocate scatterlists") Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com> Reviewed-by: Mike Christie <michael.christie@oracle.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20250628183405.3979538-1-alok.a.tiwari@oracle.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Jason Wang <jasowang@redhat.com>
generated by cgit v1.2.3 (git 2.39.0) at 2026-08-06 23:22:34 +0300