From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4644E194A60; Fri, 13 Feb 2026 15:40:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770997257; cv=none; b=DxpbxWSDC3ZVCkwoDwxxGgK/i23lyJa+7Cgd779UUKU3sl8npI3pYpmp4TfJO2Wz3de46Bgo6cX9dCXdZex4wR/OkAv9ZHAYFK4Vl52me7r+YbrkvDt1Jv6+W8D65jPtyqQptFiKAOrozqeH7uHIlai9gJIds/nTIemK8UX6vmw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770997257; c=relaxed/simple; bh=plNiWAmAz/3wmy/voy09XFl5s2ajo4x9ohqdbJJ4rkk=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version:Content-Type; b=KXuXe34I6nuUpwwqKIkEu01VwdqdDyCsWiTA0GNc6RI+kFZ1sOxOwO7WRa5lbVEAmdNVjcMIXgFO5NjXhTgwy0M0Kb9pjAtDJE2QJHTF/kR7s1q9MEz+SRAuC/Cre/LfKcmuhIaoXAVDXhA+0Cn5F358CA3E0gVmvgLO0C0ooNQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=B6BmWvTQ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="B6BmWvTQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B89F5C116C6; Fri, 13 Feb 2026 15:40:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770997256; bh=plNiWAmAz/3wmy/voy09XFl5s2ajo4x9ohqdbJJ4rkk=; h=From:To:Cc:Subject:Date:From; b=B6BmWvTQ6oxLkwDShHEjZ2I+cSALEKZsB+bepUC5KDJ1Booym1hYfPqW+dAQ+LLXE qBUwQQI+Ie2Rh4Erw7jweNllv3rxWEhouQzBXTiy4F53k8KFmk2o3mlzfbNEfRU5Rg wDJcmVEJFm0qeYyT6f7bEV0b4G6qcEu/XD9o+GwZo9kWgSwtMYtJmPmAD4Xgx3/JPH Q8heP8zdKkRWpbZxFf5MGGsy9eUQteDN3djxoLddmQdbsPw/j7UBJthj80KPy5SE50 O3qeUuygXc1r3PwHjFWFNJ3pabsAtPHNw9ATuvuB8bYhM2wcvQ8x14IuZdF+iMN+qE BoyvOF+krRuEg== From: Arnd Bergmann To: "Michael S. Tsirkin" , Jason Wang , Xie Yongji Cc: Arnd Bergmann , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , Xuan Zhuo , Marco Crivellari , Anders Roxell , virtualization@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH] [v3] vduse: fix compat handling for VDUSE_IOTLB_GET_FD/VDUSE_VQ_GET_INFO Date: Fri, 13 Feb 2026 16:40:46 +0100 Message-Id: <20260213154051.4172275-1-arnd@kernel.org> X-Mailer: git-send-email 2.39.5 Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Arnd Bergmann These two ioctls are incompatible on 32-bit x86 userspace, because the data structures are shorter than they are on 64-bit. Add a proper .compat_ioctl handler for x86 that reads the structures with the smaller padding before calling the internal handlers. On all other architectures, CONFIG_COMPAT_FOR_U64_ALIGNMENT is disabled and no special handling is required. Fixes: ad146355bfad ("vduse: Support querying information of IOVA regions") Fixes: c8a6153b6c59 ("vduse: Introduce VDUSE - vDPA Device in Userspace") Acked-by: Eugenio Pérez Signed-off-by: Arnd Bergmann --- v3 changes: - check CONFIG_COMPAT_FOR_U64_ALIGNMENT in preprocessor v2 changes: - split compat handler into separate function --- drivers/vdpa/vdpa_user/vduse_dev.c | 123 ++++++++++++++++++++++++++++- 1 file changed, 122 insertions(+), 1 deletion(-) diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c index 405d59610f76..e0f5a7397221 100644 --- a/drivers/vdpa/vdpa_user/vduse_dev.c +++ b/drivers/vdpa/vdpa_user/vduse_dev.c @@ -1618,6 +1618,127 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd, return ret; } +#ifdef CONFIG_COMPAT_FOR_U64_ALIGNMENT +/* + * i386 has different alignment constraints than x86_64, + * so there are only 3 bytes of padding instead of 7. + */ +struct compat_vduse_iotlb_entry { + compat_u64 offset; + compat_u64 start; + compat_u64 last; + __u8 perm; + __u8 padding[3]; +}; +#define COMPAT_VDUSE_IOTLB_GET_FD _IOWR(VDUSE_BASE, 0x10, struct compat_vduse_iotlb_entry) + +struct compat_vduse_vq_info { + __u32 index; + __u32 num; + compat_u64 desc_addr; + compat_u64 driver_addr; + compat_u64 device_addr; + union { + struct vduse_vq_state_split split; + struct vduse_vq_state_packed packed; + }; + __u8 ready; + __u8 padding[3]; +} __uapi_arch_align; +#define COMPAT_VDUSE_VQ_GET_INFO _IOWR(VDUSE_BASE, 0x15, struct compat_vduse_vq_info) + +static long vduse_dev_compat_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct vduse_dev *dev = file->private_data; + void __user *argp = (void __user *)arg; + int ret; + + if (unlikely(dev->broken)) + return -EPERM; + + switch (cmd) { + case COMPAT_VDUSE_IOTLB_GET_FD: { + struct vduse_iotlb_entry_v2 entry = {0}; + struct file *f = NULL; + + ret = -EFAULT; + if (copy_from_user(&entry, argp, _IOC_SIZE(cmd))) + break; + + ret = vduse_dev_iotlb_entry(dev, &entry, &f, NULL); + if (ret) + break; + + ret = -EINVAL; + if (!f) + break; + + 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.perm)); + fput(f); + break; + } + case COMPAT_VDUSE_VQ_GET_INFO: { + struct vduse_vq_info vq_info = {}; + struct vduse_virtqueue *vq; + u32 index; + + ret = -EFAULT; + if (copy_from_user(&vq_info, argp, + sizeof(struct compat_vduse_vq_info))) + break; + + ret = -EINVAL; + if (vq_info.index >= dev->vq_num) + break; + + index = array_index_nospec(vq_info.index, dev->vq_num); + vq = dev->vqs[index]; + vq_info.desc_addr = vq->desc_addr; + vq_info.driver_addr = vq->driver_addr; + vq_info.device_addr = vq->device_addr; + vq_info.num = vq->num; + + if (dev->driver_features & BIT_ULL(VIRTIO_F_RING_PACKED)) { + vq_info.packed.last_avail_counter = + vq->state.packed.last_avail_counter; + vq_info.packed.last_avail_idx = + vq->state.packed.last_avail_idx; + vq_info.packed.last_used_counter = + vq->state.packed.last_used_counter; + vq_info.packed.last_used_idx = + vq->state.packed.last_used_idx; + } else + vq_info.split.avail_index = + vq->state.split.avail_index; + + vq_info.ready = vq->ready; + + ret = -EFAULT; + if (copy_to_user(argp, &vq_info, + sizeof(struct compat_vduse_vq_info))) + break; + + ret = 0; + break; + } + default: + ret = -ENOIOCTLCMD; + break; + } + + return vduse_dev_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); +} +#else +#define vduse_dev_compat_ioctl compat_ptr_ioctl +#endif + static int vduse_dev_release(struct inode *inode, struct file *file) { struct vduse_dev *dev = file->private_data; @@ -1678,7 +1799,7 @@ static const struct file_operations vduse_dev_fops = { .write_iter = vduse_dev_write_iter, .poll = vduse_dev_poll, .unlocked_ioctl = vduse_dev_ioctl, - .compat_ioctl = compat_ptr_ioctl, + .compat_ioctl = vduse_dev_compat_ioctl, .llseek = noop_llseek, }; -- 2.39.5