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From: Claire Chang <tientzu@chromium.org>
To: Rob Herring <robh+dt@kernel.org>,
	mpe@ellerman.id.au, Joerg Roedel <joro@8bytes.org>,
	Will Deacon <will@kernel.org>,
	Frank Rowand <frowand.list@gmail.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	boris.ostrovsky@oracle.com, jgross@suse.com,
	Christoph Hellwig <hch@lst.de>,
	Marek Szyprowski <m.szyprowski@samsung.com>
Cc: benh@kernel.crashing.org, paulus@samba.org,
	"list@263.net:IOMMU DRIVERS" <iommu@lists.linux-foundation.org>,
	sstabellini@kernel.org, Robin Murphy <robin.murphy@arm.com>,
	grant.likely@arm.com, xypron.glpk@gmx.de,
	Thierry Reding <treding@nvidia.com>,
	mingo@kernel.org, bauerman@linux.ibm.com, peterz@infradead.org,
	Greg KH <gregkh@linuxfoundation.org>,
	Saravana Kannan <saravanak@google.com>,
	"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
	heikki.krogerus@linux.intel.com,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Randy Dunlap <rdunlap@infradead.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	linux-devicetree <devicetree@vger.kernel.org>,
	lkml <linux-kernel@vger.kernel.org>,
	linuxppc-dev@lists.ozlabs.org, xen-devel@lists.xenproject.org,
	Nicolas Boichat <drinkcat@chromium.org>,
	Jim Quinlan <james.quinlan@broadcom.com>,
	tfiga@chromium.org, bskeggs@redhat.com, bhelgaas@google.com,
	chris@chris-wilson.co.uk, tientzu@chromium.org, daniel@ffwll.ch,
	airlied@linux.ie, dri-devel@lists.freedesktop.org,
	intel-gfx@lists.freedesktop.org, jani.nikula@linux.intel.com,
	jxgao@google.com, joonas.lahtinen@linux.intel.com,
	linux-pci@vger.kernel.org, maarten.lankhorst@linux.intel.com,
	matthew.auld@intel.com, nouveau@lists.freedesktop.org,
	rodrigo.vivi@intel.com, thomas.hellstrom@linux.intel.com
Subject: [PATCH v6 13/15] dma-direct: Allocate memory from restricted DMA pool if available
Date: Mon, 10 May 2021 17:50:24 +0800	[thread overview]
Message-ID: <20210510095026.3477496-14-tientzu@chromium.org> (raw)
In-Reply-To: <20210510095026.3477496-1-tientzu@chromium.org>

The restricted DMA pool is preferred if available.

The restricted DMA pools provide a basic level of protection against the
DMA overwriting buffer contents at unexpected times. However, to protect
against general data leakage and system memory corruption, the system
needs to provide a way to lock down the memory access, e.g., MPU.

Note that since coherent allocation needs remapping, one must set up
another device coherent pool by shared-dma-pool and use
dma_alloc_from_dev_coherent instead for atomic coherent allocation.

Signed-off-by: Claire Chang <tientzu@chromium.org>
---
 kernel/dma/direct.c | 38 +++++++++++++++++++++++++++++---------
 1 file changed, 29 insertions(+), 9 deletions(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index eb4098323bbc..0d521f78c7b9 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -78,6 +78,10 @@ static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
 static void __dma_direct_free_pages(struct device *dev, struct page *page,
 				    size_t size)
 {
+#ifdef CONFIG_DMA_RESTRICTED_POOL
+	if (swiotlb_free(dev, page, size))
+		return;
+#endif
 	dma_free_contiguous(dev, page, size);
 }
 
@@ -92,7 +96,17 @@ static struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
 
 	gfp |= dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask,
 					   &phys_limit);
-	page = dma_alloc_contiguous(dev, size, gfp);
+
+#ifdef CONFIG_DMA_RESTRICTED_POOL
+	page = swiotlb_alloc(dev, size);
+	if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) {
+		__dma_direct_free_pages(dev, page, size);
+		page = NULL;
+	}
+#endif
+
+	if (!page)
+		page = dma_alloc_contiguous(dev, size, gfp);
 	if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) {
 		dma_free_contiguous(dev, page, size);
 		page = NULL;
@@ -148,7 +162,7 @@ void *dma_direct_alloc(struct device *dev, size_t size,
 		gfp |= __GFP_NOWARN;
 
 	if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) &&
-	    !force_dma_unencrypted(dev)) {
+	    !force_dma_unencrypted(dev) && !is_dev_swiotlb_force(dev)) {
 		page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO);
 		if (!page)
 			return NULL;
@@ -161,18 +175,23 @@ void *dma_direct_alloc(struct device *dev, size_t size,
 	}
 
 	if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&
-	    !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
-	    !dev_is_dma_coherent(dev))
+	    !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && !dev_is_dma_coherent(dev) &&
+	    !is_dev_swiotlb_force(dev))
 		return arch_dma_alloc(dev, size, dma_handle, gfp, attrs);
 
 	/*
 	 * Remapping or decrypting memory may block. If either is required and
 	 * we can't block, allocate the memory from the atomic pools.
+	 * If restricted DMA (i.e., is_dev_swiotlb_force) is required, one must
+	 * set up another device coherent pool by shared-dma-pool and use
+	 * dma_alloc_from_dev_coherent instead.
 	 */
 	if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) &&
 	    !gfpflags_allow_blocking(gfp) &&
 	    (force_dma_unencrypted(dev) ||
-	     (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && !dev_is_dma_coherent(dev))))
+	     (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
+	      !dev_is_dma_coherent(dev))) &&
+	    !is_dev_swiotlb_force(dev))
 		return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
 
 	/* we always manually zero the memory once we are done */
@@ -253,15 +272,15 @@ void dma_direct_free(struct device *dev, size_t size,
 	unsigned int page_order = get_order(size);
 
 	if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) &&
-	    !force_dma_unencrypted(dev)) {
+	    !force_dma_unencrypted(dev) && !is_dev_swiotlb_force(dev)) {
 		/* cpu_addr is a struct page cookie, not a kernel address */
 		dma_free_contiguous(dev, cpu_addr, size);
 		return;
 	}
 
 	if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&
-	    !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
-	    !dev_is_dma_coherent(dev)) {
+	    !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && !dev_is_dma_coherent(dev) &&
+	    !is_dev_swiotlb_force(dev)) {
 		arch_dma_free(dev, size, cpu_addr, dma_addr, attrs);
 		return;
 	}
@@ -289,7 +308,8 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
 	void *ret;
 
 	if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) &&
-	    force_dma_unencrypted(dev) && !gfpflags_allow_blocking(gfp))
+	    force_dma_unencrypted(dev) && !gfpflags_allow_blocking(gfp) &&
+	    !is_dev_swiotlb_force(dev))
 		return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
 
 	page = __dma_direct_alloc_pages(dev, size, gfp);
-- 
2.31.1.607.g51e8a6a459-goog



  parent reply	other threads:[~2021-05-10  9:52 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-10  9:50 [PATCH v6 00/15] Restricted DMA Claire Chang
2021-05-10  9:50 ` [PATCH v6 01/15] swiotlb: Refactor swiotlb init functions Claire Chang
2021-05-10 14:58   ` Christoph Hellwig
2021-05-10  9:50 ` [PATCH v6 02/15] swiotlb: Refactor swiotlb_create_debugfs Claire Chang
2021-05-10 14:59   ` Christoph Hellwig
2021-05-10  9:50 ` [PATCH v6 03/15] swiotlb: Add DMA_RESTRICTED_POOL Claire Chang
2021-05-10  9:50 ` [PATCH v6 04/15] swiotlb: Add restricted DMA pool initialization Claire Chang
2021-05-10 15:02   ` Christoph Hellwig
2021-05-11 16:42     ` Claire Chang
2021-05-10  9:50 ` [PATCH v6 05/15] swiotlb: Add a new get_io_tlb_mem getter Claire Chang
2021-05-10 15:03   ` Christoph Hellwig
2021-05-11 16:42     ` Claire Chang
2021-05-10  9:50 ` [PATCH v6 06/15] swiotlb: Update is_swiotlb_buffer to add a struct device argument Claire Chang
2021-05-10  9:50 ` [PATCH v6 07/15] swiotlb: Update is_swiotlb_active " Claire Chang
2021-05-10  9:50 ` [PATCH v6 08/15] swiotlb: Bounce data from/to restricted DMA pool if available Claire Chang
2021-05-10 15:05   ` Christoph Hellwig
2021-05-11 16:42     ` Claire Chang
2021-05-10  9:50 ` [PATCH v6 09/15] swiotlb: Move alloc_size to find_slots Claire Chang
2021-05-10  9:50 ` [PATCH v6 10/15] swiotlb: Refactor swiotlb_tbl_unmap_single Claire Chang
2021-05-10  9:50 ` [PATCH v6 11/15] dma-direct: Add a new wrapper __dma_direct_free_pages() Claire Chang
2021-05-10  9:50 ` [PATCH v6 12/15] swiotlb: Add restricted DMA alloc/free support Claire Chang
2021-05-10  9:50 ` Claire Chang [this message]
2021-05-10  9:50 ` [PATCH v6 14/15] dt-bindings: of: Add restricted DMA pool Claire Chang
2021-05-10  9:50 ` [PATCH v6 15/15] of: Add plumbing for " Claire Chang
2021-05-18  6:54 ` [PATCH v6 00/15] Restricted DMA Claire Chang

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