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 EB0DF36C9D8 for ; Sat, 28 Feb 2026 18:11:42 +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=1772302303; cv=none; b=cY2iP/sKqAQQwmKX3yH/2HhCHlOdnzCzCMlSZKyNqCWxyBAtI19S549OHDIwSA/w+r460FcCl/qP4ij0rjg2qufDGW1oBOJL6yemd5QAfSLwjLCLSk0iCewxlg3bQrVBW3xXTCiPQ7+rh8MkmIqUk9a3nvq+hInwNbzGZgb0//E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772302303; c=relaxed/simple; bh=oThyo1gZyDr5v6+kh6srDT8e3K0jaR6bM9PJOT/VVAc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=oxztghlErMOTlrVVyh2gVZeCYsD8HwclusGbJV1BCilAVQIHDojwQvsdO5K71gsw31wd2MtVka3n4XK2H7bE+u+9oLs+iBrn85PdWZ7fwbAvJouwriycapa4Bo53EMUC2Gq/Wd/4D1euWjhYVG+LQP22YxQy4w58rcZy47tAhIA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=uiGsIL5H; 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="uiGsIL5H" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2F9F8C116D0; Sat, 28 Feb 2026 18:11:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772302302; bh=oThyo1gZyDr5v6+kh6srDT8e3K0jaR6bM9PJOT/VVAc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uiGsIL5Hwl4R0SNiBhObQaIxWIzJvH3LJHwi9uGgjKkhUdjanLSW6Ii7yL/it6rhI gVdQF/EGHI99D5fUEYv98EqrRVk78ZIx39FuVXBvC2jHyQYiUt7+yqIruIwLIE0O5C sfiSDnS1/DJN/w4MaHD38gAjsXGYudH/moaKkobo8P2HpwtdVNB+10XHI2i78F5hW9 cuMp7MxPrLOWZ7rAGSA5a3hntHC6FfIvKsQ1QQitCmc7A30DiHKoReALV+bwMHS4mh m0iIGO7kHYCHOh0iNcswfU0dTsVn4RfVyxBCR2LkNFdILWhcn/fSLU0K0+I67PleFQ lrBr2VTQhwcTA== From: Sasha Levin To: patches@lists.linux.dev Cc: Oleksandr Tyshchenko , Xenia Ragiadakou , Stefano Stabellini , Juergen Gross , Sasha Levin Subject: [PATCH 6.1 017/232] xen/virtio: Optimize the setup of "xen-grant-dma" devices Date: Sat, 28 Feb 2026 13:07:50 -0500 Message-ID: <20260228181127.1592657-17-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260228181127.1592657-1-sashal@kernel.org> References: <20260228181127.1592657-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: Oleksandr Tyshchenko [ Upstream commit 035e3a4321f73c352b6408ec2153fa5bc3feb459 ] This is needed to avoid having to parse the same device-tree several times for a given device. For this to work we need to install the xen_virtio_restricted_mem_acc callback in Arm's xen_guest_init() which is same callback as x86's PV and HVM modes already use and remove the manual assignment in xen_setup_dma_ops(). Also we need to split the code to initialize backend_domid into a separate function. Prior to current patch we parsed the device-tree three times: 1. xen_setup_dma_ops()->...->xen_is_dt_grant_dma_device() 2. xen_setup_dma_ops()->...->xen_dt_grant_init_backend_domid() 3. xen_virtio_mem_acc()->...->xen_is_dt_grant_dma_device() With current patch we parse the device-tree only once in xen_virtio_restricted_mem_acc()->...->xen_dt_grant_init_backend_domid() Other benefits are: - Not diverge from x86 when setting up Xen grant DMA ops - Drop several global functions Signed-off-by: Oleksandr Tyshchenko Reviewed-by: Xenia Ragiadakou Reviewed-by: Stefano Stabellini Link: https://lore.kernel.org/r/20221025162004.8501-2-olekstysh@gmail.com Signed-off-by: Juergen Gross Stable-dep-of: dc8ea8714311 ("xen/virtio: Don't use grant-dma-ops when running as Dom0") Signed-off-by: Sasha Levin --- arch/arm/xen/enlighten.c | 2 +- drivers/xen/grant-dma-ops.c | 77 ++++++++++++++----------------------- include/xen/arm/xen-ops.h | 4 +- include/xen/xen-ops.h | 16 -------- 4 files changed, 30 insertions(+), 69 deletions(-) diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c index eace3607fef41..a395b6c0aae2a 100644 --- a/arch/arm/xen/enlighten.c +++ b/arch/arm/xen/enlighten.c @@ -442,7 +442,7 @@ static int __init xen_guest_init(void) return 0; if (IS_ENABLED(CONFIG_XEN_VIRTIO)) - virtio_set_mem_acc_cb(xen_virtio_mem_acc); + virtio_set_mem_acc_cb(xen_virtio_restricted_mem_acc); if (!acpi_disabled) xen_acpi_guest_init(); diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c index daa525df7bdc5..1e797a043980a 100644 --- a/drivers/xen/grant-dma-ops.c +++ b/drivers/xen/grant-dma-ops.c @@ -292,50 +292,20 @@ static const struct dma_map_ops xen_grant_dma_ops = { .dma_supported = xen_grant_dma_supported, }; -static bool xen_is_dt_grant_dma_device(struct device *dev) -{ - struct device_node *iommu_np; - bool has_iommu; - - iommu_np = of_parse_phandle(dev->of_node, "iommus", 0); - has_iommu = iommu_np && - of_device_is_compatible(iommu_np, "xen,grant-dma"); - of_node_put(iommu_np); - - return has_iommu; -} - -bool xen_is_grant_dma_device(struct device *dev) -{ - /* XXX Handle only DT devices for now */ - if (dev->of_node) - return xen_is_dt_grant_dma_device(dev); - - return false; -} - -bool xen_virtio_mem_acc(struct virtio_device *dev) -{ - if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT) || xen_pv_domain()) - return true; - - return xen_is_grant_dma_device(dev->dev.parent); -} - static int xen_dt_grant_init_backend_domid(struct device *dev, - struct xen_grant_dma_data *data) + domid_t *backend_domid) { struct of_phandle_args iommu_spec; if (of_parse_phandle_with_args(dev->of_node, "iommus", "#iommu-cells", 0, &iommu_spec)) { - dev_err(dev, "Cannot parse iommus property\n"); + dev_dbg(dev, "Cannot parse iommus property\n"); return -ESRCH; } if (!of_device_is_compatible(iommu_spec.np, "xen,grant-dma") || iommu_spec.args_count != 1) { - dev_err(dev, "Incompatible IOMMU node\n"); + dev_dbg(dev, "Incompatible IOMMU node\n"); of_node_put(iommu_spec.np); return -ESRCH; } @@ -346,12 +316,28 @@ static int xen_dt_grant_init_backend_domid(struct device *dev, * The endpoint ID here means the ID of the domain where the * corresponding backend is running */ - data->backend_domid = iommu_spec.args[0]; + *backend_domid = iommu_spec.args[0]; return 0; } -void xen_grant_setup_dma_ops(struct device *dev) +static int xen_grant_init_backend_domid(struct device *dev, + domid_t *backend_domid) +{ + int ret = -ENODEV; + + if (dev->of_node) { + ret = xen_dt_grant_init_backend_domid(dev, backend_domid); + } else if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT) || xen_pv_domain()) { + dev_info(dev, "Using dom0 as backend\n"); + *backend_domid = 0; + ret = 0; + } + + return ret; +} + +static void xen_grant_setup_dma_ops(struct device *dev, domid_t backend_domid) { struct xen_grant_dma_data *data; @@ -365,16 +351,7 @@ void xen_grant_setup_dma_ops(struct device *dev) if (!data) goto err; - if (dev->of_node) { - if (xen_dt_grant_init_backend_domid(dev, data)) - goto err; - } else if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT)) { - dev_info(dev, "Using dom0 as backend\n"); - data->backend_domid = 0; - } else { - /* XXX ACPI device unsupported for now */ - goto err; - } + data->backend_domid = backend_domid; if (store_xen_grant_dma_data(dev, data)) { dev_err(dev, "Cannot store Xen grant DMA data\n"); @@ -392,12 +369,14 @@ void xen_grant_setup_dma_ops(struct device *dev) bool xen_virtio_restricted_mem_acc(struct virtio_device *dev) { - bool ret = xen_virtio_mem_acc(dev); + domid_t backend_domid; - if (ret) - xen_grant_setup_dma_ops(dev->dev.parent); + if (!xen_grant_init_backend_domid(dev->dev.parent, &backend_domid)) { + xen_grant_setup_dma_ops(dev->dev.parent, backend_domid); + return true; + } - return ret; + return false; } MODULE_DESCRIPTION("Xen grant DMA-mapping layer"); diff --git a/include/xen/arm/xen-ops.h b/include/xen/arm/xen-ops.h index b0766a660338f..70073f5a2b545 100644 --- a/include/xen/arm/xen-ops.h +++ b/include/xen/arm/xen-ops.h @@ -8,9 +8,7 @@ static inline void xen_setup_dma_ops(struct device *dev) { #ifdef CONFIG_XEN - if (xen_is_grant_dma_device(dev)) - xen_grant_setup_dma_ops(dev); - else if (xen_swiotlb_detect()) + if (xen_swiotlb_detect()) dev->dma_ops = &xen_swiotlb_dma_ops; #endif } diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h index a34f4271a2e9f..47f11bec5e90c 100644 --- a/include/xen/xen-ops.h +++ b/include/xen/xen-ops.h @@ -216,26 +216,10 @@ static inline void xen_preemptible_hcall_end(void) { } #endif /* CONFIG_XEN_PV && !CONFIG_PREEMPTION */ #ifdef CONFIG_XEN_GRANT_DMA_OPS -void xen_grant_setup_dma_ops(struct device *dev); -bool xen_is_grant_dma_device(struct device *dev); -bool xen_virtio_mem_acc(struct virtio_device *dev); bool xen_virtio_restricted_mem_acc(struct virtio_device *dev); #else -static inline void xen_grant_setup_dma_ops(struct device *dev) -{ -} -static inline bool xen_is_grant_dma_device(struct device *dev) -{ - return false; -} - struct virtio_device; -static inline bool xen_virtio_mem_acc(struct virtio_device *dev) -{ - return false; -} - static inline bool xen_virtio_restricted_mem_acc(struct virtio_device *dev) { return false; -- 2.51.0