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 C03CA2D77E3; Mon, 2 Feb 2026 22:48:56 +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=1770072536; cv=none; b=JQNeaA9IK2S3EhmP/6gSM8PCB+aMu4A75Zuz4p80Ro6gJfRSUOldU6MMTlHrfFM5RKYmc4z5vSe8J/YMNJjsbTbsgvSmbs8JRefR6hQS71BNNp9CCaJkQ6d4Iu34SVA+sa4GlcxQv9JSBEDSl22U7sonoGkH8tZ/UzKiCyvQsA0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770072536; c=relaxed/simple; bh=2SQk6akRnaJrtIkyw0e1kuGJW8iEQ/1VXNLrxse1/Lc=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=MvmlV+fzH8a+UgumZc89tkPmbe19PWnM9k6amEeCjCXl+Zpoi235GInd4ALdjivAMgNjX28ITyq7LGmIoWQRTYAA3aUj0NSTD1pzj+AgBn0G9H4XEdzAAnlXoA9sQ4QCToVL681DO4cd3zTRtfhENw28Yzz+sIjQ2EN8eCNfufc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AjWyEUAf; 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="AjWyEUAf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DFCA0C116C6; Mon, 2 Feb 2026 22:48:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770072536; bh=2SQk6akRnaJrtIkyw0e1kuGJW8iEQ/1VXNLrxse1/Lc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AjWyEUAfT3DxKONc8hQCQSbOvfqFjl9L6OdMc658VwYjwwxemxAfJSaaD9MoJWQ6W ayf/9mrv1HEj5uSWPuFI60ab34RQl9J4FZ982INCFeaFsinCDW8XbtGlBshjgdnLq8 m5ZFoAs1yFx8eBrsZ64+IJjWnUUmMp2FOAwSm82HnCsF5kYribq0vYgPL/nb5K58x3 jrWj4pTqrCmPvZFz4hpgJLsUwSt86fgoj2llStxffae4dLfch8DTNCVzBom0hOZm5z bSUIWA9IpDYZF4YwvFIJpDhDCGl/CSoOX6jSsm9xMtgrixKA9mLdYMu5IYDZPdpB3x DXfBF/pBAxaaA== From: Arnd Bergmann To: "Michael S. Tsirkin" , Jason Wang , Xie Yongji Cc: Arnd Bergmann , Xuan Zhuo , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , virtualization@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH 2/2] [v2] vduse: fix compat handling for VDUSE_IOTLB_GET_FD/VDUSE_VQ_GET_INFO Date: Mon, 2 Feb 2026 23:48:08 +0100 Message-Id: <20260202224835.559538-2-arnd@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20260202224835.559538-1-arnd@kernel.org> References: <20260202224835.559538-1-arnd@kernel.org> Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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. Fixes: ad146355bfad ("vduse: Support querying information of IOVA regions") Fixes: c8a6153b6c59 ("vduse: Introduce VDUSE - vDPA Device in Userspace") Signed-off-by: Arnd Bergmann --- The code is directly copied from the native ioctl handler, but I did not test this with actual x86-32 userspace, so please review carefully. --- 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..3ada167ac260 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; } +/* + * 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[__alignof__(compat_u64) - 1]; +}; +#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[__alignof__(compat_u64) - 1]; +} __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 (!IS_ENABLED(CONFIG_X86_64)) + return vduse_dev_ioctl(file, cmd, + (unsigned long)compat_ptr(arg)); + + 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)); +} + 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 = PTR_IF(IS_ENABLED(CONFIG_COMPAT), vduse_dev_compat_ioctl), .llseek = noop_llseek, }; -- 2.39.5