From patchwork Tue Jul 4 08:06:27 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mattias Nissler X-Patchwork-Id: 13300758 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5E647EB64D9 for ; Tue, 4 Jul 2023 08:07:56 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qGb3l-0006mT-Mq; Tue, 04 Jul 2023 04:06:53 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qGb3k-0006lw-Db for qemu-devel@nongnu.org; Tue, 04 Jul 2023 04:06:52 -0400 Received: from mail-pf1-x436.google.com ([2607:f8b0:4864:20::436]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qGb3h-0000vm-TZ for qemu-devel@nongnu.org; Tue, 04 Jul 2023 04:06:52 -0400 Received: by mail-pf1-x436.google.com with SMTP id d2e1a72fcca58-66869feb7d1so2695492b3a.3 for ; Tue, 04 Jul 2023 01:06:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rivosinc-com.20221208.gappssmtp.com; s=20221208; t=1688458008; x=1691050008; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=HFNNCtPqWtjxwt+qHGQAYUqPKlbWW72Qgk4NOXVFZYs=; b=eTaoSz2JvUQBoObqpxPhXdllw0/5dtohOVJgEYDXlmPmVinyMJJ6FCRDHaPJwiBWom y+ERZPfp4ATyBLKp7kG8BJyrZ3n4HKPWj/GfZcWG0XnLWoVm7xMKOP4nSX23fbLjsfQE J6+cQkqDWdHdqdAy1sCqDrsRVln/6m5FhaN6mlUpzfgY5q3olxs4vL0yL1Yhw0+gYpyk kOoUe2VVKagDNMJ0gTlA3szD8tE62mPfwsHR5ZYs5gjwodGFvqsDcwemYlgySMlwnr7H o+1H7psjPle4d4fZ/ur70nZCFGM6AaNbZ+JtfymairvpDx7vl+tb5AmBfzJe4I1Yg1LI DcEQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1688458008; x=1691050008; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=HFNNCtPqWtjxwt+qHGQAYUqPKlbWW72Qgk4NOXVFZYs=; b=iAUHhUpCWgSZAclyNxJQahgg0HcnozkuwVf/bIXMt4TVqvN/lFKi2JzC276sxnbX/H IAb4xeTEaRZtsPRowIsiYFbXze0y2/PR/xKEmdvtsPByqm3GmfrL/e8TekyN+LdNdWna RCuQSeNwXdc6KjW7jEErwjbRmONX8P0nOUKeC/sZgzhhMkChG0vUzDRIWTvU69bujBDI RzbDaZd6cq9CWQf9d8geulBvyG92z1nC366EnrTWlcJD8QfHos5U3ZNducEJyUrfve1k tlnIgf45Jb+FnwRdx++TUy+do0ER3z6Ldk4MqAYe5dLzr5qWzAPbsT3YJ/mqdXmgA4+V A1fA== X-Gm-Message-State: ABy/qLbg6Ec1Bz93Td+KDsT8zbVSRKUe3epUAufvXCvwmxbXzaqE71RF lAXXdxQsJnM+qa0oySzzh/BCVf+YGYw7H6HVDwafdQ== X-Google-Smtp-Source: APBJJlGtzmlW93GdkFzk6DhoIma8WvJ/stKAWNA4/HrG7+vMFWpI8sy868TGWeoWVvH3cxmMVzeLVQ== X-Received: by 2002:a05:6a00:1910:b0:668:7744:10f5 with SMTP id y16-20020a056a00191000b00668774410f5mr13299584pfi.10.1688458008534; Tue, 04 Jul 2023 01:06:48 -0700 (PDT) Received: from mnissler.ba.rivosinc.com ([66.220.2.162]) by smtp.gmail.com with ESMTPSA id u1-20020aa78381000000b00662c4ca18ebsm15113101pfm.128.2023.07.04.01.06.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 Jul 2023 01:06:48 -0700 (PDT) From: Mattias Nissler To: qemu-devel@nongnu.org Cc: Elena Ufimtseva , Jagannathan Raman , =?utf-8?q?Philippe_Mathieu-Daud?= =?utf-8?q?=C3=A9?= , Paolo Bonzini , Peter Xu , stefanha@redhat.com, David Hildenbrand , john.levon@nutanix.com, Mattias Nissler Subject: [PATCH 3/3] vfio-user: Message-based DMA support Date: Tue, 4 Jul 2023 01:06:27 -0700 Message-Id: <20230704080628.852525-4-mnissler@rivosinc.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230704080628.852525-1-mnissler@rivosinc.com> References: <20230704080628.852525-1-mnissler@rivosinc.com> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::436; envelope-from=mnissler@rivosinc.com; helo=mail-pf1-x436.google.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Wire up support for DMA for the case where the vfio-user client does not provide mmap()-able file descriptors, but DMA requests must be performed via the VFIO-user protocol. This installs an indirect memory region, which already works for pci_dma_{read,write}, and pci_dma_map works thanks to the existing DMA bounce buffering support. Note that while simple scenarios work with this patch, there's a known race condition in libvfio-user that will mess up the communication channel: https://github.com/nutanix/libvfio-user/issues/279 I intend to contribute a fix for this problem, see discussion on the github issue for more details. Signed-off-by: Mattias Nissler --- hw/remote/vfio-user-obj.c | 62 ++++++++++++++++++++++++++++++++++----- 1 file changed, 55 insertions(+), 7 deletions(-) diff --git a/hw/remote/vfio-user-obj.c b/hw/remote/vfio-user-obj.c index 8b10c32a3c..9799580c77 100644 --- a/hw/remote/vfio-user-obj.c +++ b/hw/remote/vfio-user-obj.c @@ -300,6 +300,53 @@ static ssize_t vfu_object_cfg_access(vfu_ctx_t *vfu_ctx, char * const buf, return count; } +static MemTxResult vfu_dma_read(void *opaque, hwaddr addr, uint64_t *val, + unsigned size, MemTxAttrs attrs) +{ + MemoryRegion *region = opaque; + VfuObject *o = VFU_OBJECT(region->owner); + + dma_sg_t *sg = alloca(dma_sg_size()); + vfu_dma_addr_t vfu_addr = (vfu_dma_addr_t)(region->addr + addr); + if (vfu_addr_to_sgl(o->vfu_ctx, vfu_addr, size, sg, 1, PROT_READ) < 0 || + vfu_sgl_read(o->vfu_ctx, sg, 1, val) != 0) { + return MEMTX_ERROR; + } + + return MEMTX_OK; +} + +static MemTxResult vfu_dma_write(void *opaque, hwaddr addr, uint64_t val, + unsigned size, MemTxAttrs attrs) +{ + MemoryRegion *region = opaque; + VfuObject *o = VFU_OBJECT(region->owner); + + dma_sg_t *sg = alloca(dma_sg_size()); + vfu_dma_addr_t vfu_addr = (vfu_dma_addr_t)(region->addr + addr); + if (vfu_addr_to_sgl(o->vfu_ctx, vfu_addr, size, sg, 1, PROT_WRITE) < 0 || + vfu_sgl_write(o->vfu_ctx, sg, 1, &val) != 0) { + return MEMTX_ERROR; + } + + return MEMTX_OK; +} + +static const MemoryRegionOps vfu_dma_ops = { + .read_with_attrs = vfu_dma_read, + .write_with_attrs = vfu_dma_write, + .endianness = DEVICE_NATIVE_ENDIAN, + .valid = { + .min_access_size = 1, + .max_access_size = 8, + .unaligned = true, + }, + .impl = { + .min_access_size = 1, + .max_access_size = 8, + }, +}; + static void dma_register(vfu_ctx_t *vfu_ctx, vfu_dma_info_t *info) { VfuObject *o = vfu_get_private(vfu_ctx); @@ -308,17 +355,18 @@ static void dma_register(vfu_ctx_t *vfu_ctx, vfu_dma_info_t *info) g_autofree char *name = NULL; struct iovec *iov = &info->iova; - if (!info->vaddr) { - return; - } - name = g_strdup_printf("mem-%s-%"PRIx64"", o->device, - (uint64_t)info->vaddr); + (uint64_t)iov->iov_base); subregion = g_new0(MemoryRegion, 1); - memory_region_init_ram_ptr(subregion, NULL, name, - iov->iov_len, info->vaddr); + if (info->vaddr) { + memory_region_init_ram_ptr(subregion, OBJECT(o), name, + iov->iov_len, info->vaddr); + } else { + memory_region_init_io(subregion, OBJECT(o), &vfu_dma_ops, subregion, + name, iov->iov_len); + } dma_as = pci_device_iommu_address_space(o->pci_dev);