From nobody Mon Mar 2 11:00:50 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=intel.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1772230916906904.5099359649846; Fri, 27 Feb 2026 14:21:56 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vw6Bc-000643-ID; Fri, 27 Feb 2026 17:19:52 -0500 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 1vw6Ba-00063m-P8 for qemu-devel@nongnu.org; Fri, 27 Feb 2026 17:19:51 -0500 Received: from mgamail.intel.com ([198.175.65.16]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vw6BY-0007ml-Oe for qemu-devel@nongnu.org; Fri, 27 Feb 2026 17:19:50 -0500 Received: from fmviesa003.fm.intel.com ([10.60.135.143]) by orvoesa108.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Feb 2026 14:19:40 -0800 Received: from vkasired-desk2.fm.intel.com ([10.105.128.132]) by fmviesa003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Feb 2026 14:19:40 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1772230789; x=1803766789; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=lYWaP1kFmLOPTRi7iW/x1sxii0x816fC62gZjXLi8LA=; b=bxSWjjSzkSYA9RVpv4bDiglpYgJ1QB9TOkQDCmqEW2eHipFIl/txY/gk 29x+cQLYZztibDXH7KOMSJlXEwkR7MlsnkzUJHwnRQYHLsJyzUmC3wO6d 2P6jAtHpWwpPGiOo0vnbJsafVnH+32xUZqDnlTVdMy7/B3i3d/WUto4Uf IXhVwj6wxug6G5b8eCnO8ArQqN3y98/zibJfnq+aGRb0Y2PV0kKmjTU0u 6tdkuU1vdNYyG2/xMTBWz/gt1cO8SYj74TTDvlf+7XIksqHazgAE46rmk 1TAiWvWkjwqkX7hdPhGAhix/8TRyq/9ATymBku90RR0G+dSlrfHxm+Jpf Q==; X-CSE-ConnectionGUID: B8lLo1vORSG7NMPc+l6E7g== X-CSE-MsgGUID: izsXlQnOTDWxF2ZcOvm4NQ== X-IronPort-AV: E=McAfee;i="6800,10657,11714"; a="73509333" X-IronPort-AV: E=Sophos;i="6.21,314,1763452800"; d="scan'208";a="73509333" X-CSE-ConnectionGUID: udaJMluJTZKqf5kGTm4e/Q== X-CSE-MsgGUID: HDsMqSXNR8SnSxS1J458Ww== X-ExtLoop1: 1 From: Vivek Kasireddy To: qemu-devel@nongnu.org Cc: Vivek Kasireddy , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , =?UTF-8?q?Alex=20Benn=C3=A9e?= , Akihiko Odaki , Dmitry Osipenko , Alex Williamson , =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= Subject: [PATCH v8 02/10] virtio-gpu: Find hva for Guest's DMA addr associated with a ram device Date: Fri, 27 Feb 2026 14:13:48 -0800 Message-ID: <20260227221632.827046-3-vivek.kasireddy@intel.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260227221632.827046-1-vivek.kasireddy@intel.com> References: <20260227221632.827046-1-vivek.kasireddy@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=198.175.65.16; envelope-from=vivek.kasireddy@intel.com; helo=mgamail.intel.com X-Spam_score_int: -32 X-Spam_score: -3.3 X-Spam_bar: --- X-Spam_report: (-3.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.706, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.401, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 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: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZM-MESSAGEID: 1772230932143158502 If the Guest provides a DMA address that is associated with a ram device (such as a VFIO PCI device region and not its system memory), then we can obtain the hva (host virtual address) by invoking address_space_translate() followed by memory_region_get_ram_ptr(). We cannot use dma_memory_map() because for memory regions that do not support direct access, it would create bounce buffers instead of returning the actual hva, which is not desirable here. And, since VFIO device regions are not considered directly accessible (because they are mostly MMIO based), virtio-gpu cannot invoke dma_memory_map() to obtain the hva in this case. Therefore, in order to handle addresses associated with VFIO devices, we need to use the address_space_translate() API to first identify the right memory region and the appropriate offset within that region and then use memory_region_get_ram_ptr() to get the hva. This approach also works for addresses associated with the system memory region. Note that, although we take an explicit reference on the memory region, we would still rely on dma_memory_unmap() to drop that reference when the dma mapping is eventually unmapped. Cc: Marc-Andr=C3=A9 Lureau Cc: Alex Benn=C3=A9e Cc: Akihiko Odaki Cc: Dmitry Osipenko Cc: Alex Williamson Cc: C=C3=A9dric Le Goater Reviewed-by: Akihiko Odaki Signed-off-by: Vivek Kasireddy --- hw/display/virtio-gpu.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/hw/display/virtio-gpu.c b/hw/display/virtio-gpu.c index f20111fa57..f5c6a7deb9 100644 --- a/hw/display/virtio-gpu.c +++ b/hw/display/virtio-gpu.c @@ -798,6 +798,23 @@ static void virtio_gpu_set_scanout_blob(VirtIOGPU *g, &fb, res, &ss.r, &cmd->error); } =20 +static void *virtio_gpu_dma_memory_map(VirtIOGPU *g, + struct virtio_gpu_ctrl_command *cmd, + uint64_t a, hwaddr *len) +{ + MemoryRegion *mr; + hwaddr xlat; + + mr =3D address_space_translate(VIRTIO_DEVICE(g)->dma_as, a, &xlat, len, + DMA_DIRECTION_TO_DEVICE, + MEMTXATTRS_UNSPECIFIED); + if (memory_region_is_ram(mr)) { + memory_region_ref(mr); + return memory_region_get_ram_ptr(mr) + xlat; + } + return NULL; +} + int virtio_gpu_create_mapping_iov(VirtIOGPU *g, uint32_t nr_entries, uint32_t offset, struct virtio_gpu_ctrl_command *cmd, @@ -839,9 +856,7 @@ int virtio_gpu_create_mapping_iov(VirtIOGPU *g, =20 do { len =3D l; - map =3D dma_memory_map(VIRTIO_DEVICE(g)->dma_as, a, &len, - DMA_DIRECTION_TO_DEVICE, - MEMTXATTRS_UNSPECIFIED); + map =3D virtio_gpu_dma_memory_map(g, cmd, a, &len); if (!map) { qemu_log_mask(LOG_GUEST_ERROR, "%s: failed to map MMIO mem= ory for" " element %d\n", __func__, e); --=20 2.53.0