From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) (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 2358C245005; Mon, 3 Nov 2025 20:08:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=67.231.145.42 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762200488; cv=none; b=b4AgGXutBmeomyZ9jcgHDoxIV2iHnjKYFhs/p7uyVQymG+N9b6foZZLSQcfSVXVZYkAZd9FCuGnPnozncOglYPsdkUZbimxeTBwcpJuxfA4UM/MTIlJwv3FYkBnBowSnUpPkyvgpFgtDL8zwlJHD84d0UuE3LdoS2cMM8xH74J8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762200488; c=relaxed/simple; bh=bOZFIe2RQWsHY3f7hDWHXpv++tj6j9WWgZ4tTtaKlRA=; h=Date:From:To:CC:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=S5pFkc59spoeIdRnn37DrwArmI1at8FtCNXp4s58ISK1PSC5ZJCL1D1dzY8aq223C9FIoMBaM42qZw1YWd6i6z4buGcyUUZJSVbFkMIYTJG8yy0a+wmiWiWPtYNTQU+Js+2WH8PjstPHCpNNUs7G5aygnc8HBO4SAUnWQsVLneA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fb.com; spf=pass smtp.mailfrom=meta.com; dkim=pass (2048-bit key) header.d=fb.com header.i=@fb.com header.b=Y5TYvio2; arc=none smtp.client-ip=67.231.145.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fb.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=meta.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=fb.com header.i=@fb.com header.b="Y5TYvio2" Received: from pps.filterd (m0044012.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 5A3HSUl13368916; Mon, 3 Nov 2025 12:07:21 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=cc :content-type:date:from:in-reply-to:message-id:mime-version :references:subject:to; s=s2048-2025-q2; bh=n9Hp+W96E82ffeM9TGY/ T64q12eMoTlbRaWkBHrOVhQ=; b=Y5TYvio2wy42a6OuNV1jizo/aQU5rL6HohWI OdRswHnuwgKDGg4PRZorsSwOwSWNepxL3lv6e92F0ZZiEQOO8ZMDqwElBWya7VYx yHZJ1Bg/rdGSvGKN1xCect7aLk4BJP3dFq0W4bRU4thNy47l/7qf6QCLDdrJWuYT ttchffm5fJ8azlwk2GD5NtPH33FSvCNhfhPKLPVh0Qs6M/RaBFY1LsIhyFIHXKOv PPwMbL4I1eFF62/08bb33eCUiaTLoRka7NFBHCCzuXtuZDc3HhRZW8A7Jd4FsCBj aU36aw88WsqWA0jpB+Nf9LOBQRQOfcCvornGVmHGoYNGSzpsQw== Received: from mail.thefacebook.com ([163.114.134.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 4a6yfe2849-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT); Mon, 03 Nov 2025 12:07:21 -0800 (PST) Received: from devgpu015.cco6.facebook.com (2620:10d:c085:208::7cb7) by mail.thefacebook.com (2620:10d:c08b:78::c78f) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.2.2562.20; Mon, 3 Nov 2025 20:07:19 +0000 Date: Mon, 3 Nov 2025 12:07:12 -0800 From: Alex Mastro To: Leon Romanovsky CC: Bjorn Helgaas , Logan Gunthorpe , Jens Axboe , Robin Murphy , Joerg Roedel , Will Deacon , Marek Szyprowski , Jason Gunthorpe , Andrew Morton , Jonathan Corbet , Sumit Semwal , Christian =?iso-8859-1?Q?K=F6nig?= , Alex Williamson , Kees Cook , "Gustavo A. R. Silva" , Ankit Agrawal , Yishai Hadas , Shameer Kolothum , Kevin Tian , Krishnakant Jaju , Matt Ochs , , , , , , , , , , , , Vivek Kasireddy Subject: Re: [PATCH v6 00/11] vfio/pci: Allow MMIO regions to be exported through dma-buf Message-ID: References: <20251102-dmabuf-vfio-v6-0-d773cff0db9f@nvidia.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20251102-dmabuf-vfio-v6-0-d773cff0db9f@nvidia.com> X-Authority-Analysis: v=2.4 cv=G9QR0tk5 c=1 sm=1 tr=0 ts=69090b79 cx=c_pps a=CB4LiSf2rd0gKozIdrpkBw==:117 a=CB4LiSf2rd0gKozIdrpkBw==:17 a=kj9zAlcOel0A:10 a=6UeiqGixMTsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=FOH2dFAWAAAA:8 a=b_Saz7MSmFOFN_6dvx4A:9 a=CjuIK1q_8ugA:10 a=DXsff8QfwkrTrK3sU8N1:22 a=Z5ABNNGmrOfJ6cZ5bIyy:22 a=bWyr8ysk75zN3GCy5bjg:22 X-Proofpoint-ORIG-GUID: F1nk6hmysPbKhKVQa_mqqIFKqOIt2lHM X-Proofpoint-GUID: F1nk6hmysPbKhKVQa_mqqIFKqOIt2lHM X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMTAzMDE3OSBTYWx0ZWRfX6SW28Xvycs0O YOKukhqpHcTfkYNeGRk02UVQnYAieNl0FPP5nyOoQsMjQfkPKcUonaa3EWc/tqdoAAQyhyOyp0d /JHwcN3QLYQ/+EZJhZ2InHvQ5+q0ThEzTdyBEGsfGK6Opxy38U0CpsznUzKLwU/5Eqh1l493VDE PyTsfwJm0au//MmeaXH4NXKBaJs6mnL334sMoj6rtJQYWDX5DKMNRtgxvcMAQid95nsgniy4DYE +umaq/vNBvV3b0K6HXe0s/cT+YOR8m2DkpctVf5zXXorytYnhbn1vV3nGRWxaQ24cLeCzQnNSqB UmVF2ZqiQwbE9Yb71RMC4EJcfgbsbmodipz9oljstvRLhQ7lzspcSOdC0w5Z4QcLNUWGre4urgV ZaziQQl4T7tsVkAKgmifB2A8A6gzCQ== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-11-03_04,2025-11-03_03,2025-10-01_01 On Sun, Nov 02, 2025 at 10:00:48AM +0200, Leon Romanovsky wrote: > Changelog: > v6: > * Fixed wrong error check from pcim_p2pdma_init(). > * Documented pcim_p2pdma_provider() function. > * Improved commit messages. > * Added VFIO DMA-BUF selftest. > * Added __counted_by(nr_ranges) annotation to struct vfio_device_feature_dma_buf. > * Fixed error unwind when dma_buf_fd() fails. > * Document latest changes to p2pmem. > * Removed EXPORT_SYMBOL_GPL from pci_p2pdma_map_type. > * Moved DMA mapping logic to DMA-BUF. > * Removed types patch to avoid dependencies between subsystems. > * Moved vfio_pci_dma_buf_move() in err_undo block. > * Added nvgrace patch. Thanks Leon. Attaching a toy program which sanity tests the dma-buf export UAPI by feeding the allocated dma-buf into an dma-buf importer (libibverbs + CX-7). Tested-by: Alex Mastro $ cc -Og -Wall -Wextra $(pkg-config --cflags --libs libibverbs) test_dmabuf.c -o test_dmabuf $ ./test_dmabuf 0000:05:00.0 3 4 0 0x1000 opening 0000:05:00.0 via /dev/vfio/56 allocating dma_buf bar_idx=4, bar_offset=0x0, size=0x1000 allocated dma_buf fd=6 discovered 4 ibv devices: mlx5_0 mlx5_1 mlx5_2 mlx5_3 opened ibv device 3: mlx5_3 registered dma_buf unregistered dma_buf closed dma_buf fd --- #include #include #include #include #include #include #include #include #include #include #include #include #define ensure(cond) \ do { \ if (!(cond)) { \ fprintf(stderr, \ "%s:%d Condition failed: '%s' (errno=%d: %s)\n", \ __FILE__, __LINE__, #cond, errno, \ strerror(errno)); \ exit(EXIT_FAILURE); \ } \ } while (0) #ifndef VFIO_DEVICE_FEATURE_DMA_BUF #define VFIO_DEVICE_FEATURE_DMA_BUF 11 struct vfio_region_dma_range { __u64 offset; __u64 length; }; struct vfio_device_feature_dma_buf { __u32 region_index; __u32 open_flags; __u32 flags; __u32 nr_ranges; struct vfio_region_dma_range dma_ranges[]; }; #endif static uint32_t group_for_bdf(const char *bdf) { char path[PATH_MAX]; char link[PATH_MAX]; int ret; snprintf(path, sizeof(path), "/sys/bus/pci/devices/%s/iommu_group", bdf); ret = readlink(path, link, sizeof(link)); ensure(ret > 0); const char *filename = basename(link); ensure(filename); return strtoul(filename, NULL, 0); } int main(int argc, char **argv) { int ret; if (argc != 6) { printf("usage: %s \n", argv[0]); printf("example: %s 0000:05:00.0 3 2 0x20000 0x1000\n", argv[0]); return 1; } const char *bdf = argv[1]; uint32_t ibv_idx = strtoul(argv[2], NULL, 0); uint32_t bar_idx = strtoul(argv[3], NULL, 0); uint64_t bar_offs = strtoull(argv[4], NULL, 0); uint64_t dmabuf_len = strtoull(argv[5], NULL, 0); uint32_t group_num = group_for_bdf(bdf); char group_path[PATH_MAX]; snprintf(group_path, sizeof(group_path), "/dev/vfio/%u", group_num); int container_fd = open("/dev/vfio/vfio", O_RDWR); ensure(container_fd >= 0); printf("opening %s via %s\n", bdf, group_path); int group_fd = open(group_path, O_RDWR); ensure(group_fd >= 0); ret = ioctl(group_fd, VFIO_GROUP_SET_CONTAINER, &container_fd); ensure(!ret); ret = ioctl(container_fd, VFIO_SET_IOMMU, VFIO_TYPE1v2_IOMMU); ensure(!ret); int device_fd = ioctl(group_fd, VFIO_GROUP_GET_DEVICE_FD, bdf); ensure(device_fd >= 0); uint8_t buf[sizeof(struct vfio_device_feature) + sizeof(struct vfio_device_feature_dma_buf) + sizeof(struct vfio_region_dma_range)] __attribute__((aligned(32))); struct vfio_device_feature *ft = (struct vfio_device_feature *)buf; *ft = (struct vfio_device_feature){ .argsz = sizeof(buf), .flags = VFIO_DEVICE_FEATURE_GET | VFIO_DEVICE_FEATURE_DMA_BUF, }; struct vfio_device_feature_dma_buf *ft_dma_buf = (struct vfio_device_feature_dma_buf *)ft->data; *ft_dma_buf = (struct vfio_device_feature_dma_buf){ .region_index = bar_idx, .open_flags = O_RDWR, .nr_ranges = 1, }; ft_dma_buf->dma_ranges[0] = (struct vfio_region_dma_range){ .length = dmabuf_len, .offset = bar_offs, }; printf("allocating dma_buf bar_idx=%u, bar_offset=0x%lx, size=0x%lx\n", bar_idx, bar_offs, dmabuf_len); int dmabuf_fd = ioctl(device_fd, VFIO_DEVICE_FEATURE, buf); ensure(dmabuf_fd >= 0); printf("allocated dma_buf fd=%d\n", dmabuf_fd); int num; struct ibv_device **devs = ibv_get_device_list(&num); ensure(devs && num > 0); printf("discovered %d ibv devices:", num); for (int i = 0; i < num; i++) { printf(" %s", ibv_get_device_name(devs[i])); } printf("\n"); ensure(ibv_idx < (uint32_t)num); struct ibv_context *ctx = ibv_open_device(devs[ibv_idx]); ensure(ctx); printf("opened ibv device %d: %s\n", ibv_idx, ibv_get_device_name(devs[ibv_idx])); struct ibv_pd *pd = ibv_alloc_pd(ctx); ensure(pd); uint64_t offset = 0; uint64_t iova = 0; int access = IBV_ACCESS_LOCAL_WRITE | IBV_ACCESS_REMOTE_READ | IBV_ACCESS_REMOTE_WRITE; struct ibv_mr *mr = ibv_reg_dmabuf_mr(pd, offset, dmabuf_len, iova, dmabuf_fd, access); ensure(mr); printf("registered dma_buf\n"); ret = ibv_dereg_mr(mr); ensure(!ret); printf("unregistered dma_buf\n"); ret = close(dmabuf_fd); ensure(!ret); printf("closed dma_buf fd\n"); return 0; } ---