Linux IOMMU Development
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From: Lu Baolu <baolu.lu@linux.intel.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: intel-gfx@lists.freedesktop.org,
	Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Jani Nikula <jani.nikula@linux.intel.com>,
	iommu@lists.linux-foundation.org, Tom Murphy <murphyt7@tcd.ie>,
	Rodrigo Vivi <rodrigo.vivi@intel.com>,
	David Woodhouse <dwmw2@infradead.org>
Subject: Re: [PATCH V2 5/5] DO NOT MERGE: iommu: disable list appending in dma-iommu
Date: Wed, 9 Sep 2020 09:43:09 +0800	[thread overview]
Message-ID: <a10026ea-6de5-b7b1-80af-8000dfd4601b@linux.intel.com> (raw)
In-Reply-To: <20200908062326.GB20774@infradead.org>

Hi Christoph,

On 9/8/20 2:23 PM, Christoph Hellwig wrote:
> On Tue, Sep 08, 2020 at 02:04:53PM +0800, Lu Baolu wrote:
>> Do you mind telling where can I find Marek's series?
> 
> [PATCH v10 00/30] DRM: fix struct sg_table nents vs. orig_nents misuse
> 
> on various lists including the iommu one.
> 

It seems that more work is needed in i915 driver. I will added below
quirk as you suggested.

--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -851,6 +851,31 @@ static int __finalise_sg(struct device *dev, struct 
scatterlist *sg, int nents,
         unsigned int cur_len = 0, max_len = dma_get_max_seg_size(dev);
         int i, count = 0;

+       /*
+        * The Intel graphic device driver is used to assume that the 
returned
+        * sg list is not combound. This blocks the efforts of 
converting the
+        * Intel IOMMU driver to dma-iommu api's. Add this quirk to make the
+        * device driver work and should be removed once it's fixed in i915
+        * driver.
+        */
+       if (dev_is_pci(dev) &&
+           to_pci_dev(dev)->vendor == PCI_VENDOR_ID_INTEL &&
+           (to_pci_dev(dev)->class >> 16) == PCI_BASE_CLASS_DISPLAY) {
+               for_each_sg(sg, s, nents, i) {
+                       unsigned int s_iova_off = sg_dma_address(s);
+                       unsigned int s_length = sg_dma_len(s);
+                       unsigned int s_iova_len = s->length;
+
+                       s->offset += s_iova_off;
+                       s->length = s_length;
+                       sg_dma_address(s) = dma_addr + s_iova_off;
+                       sg_dma_len(s) = s_length;
+                       dma_addr += s_iova_len;
+               }
+
+               return nents;
+       }
+

Best regards,
baolu
_______________________________________________
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iommu@lists.linux-foundation.org
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  parent reply	other threads:[~2020-09-09  1:49 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-03 20:18 [PATCH V2 0/5] Convert the intel iommu driver to the dma-iommu api Tom Murphy
2020-09-03 20:18 ` [PATCH V2 1/5] iommu: Handle freelists when using deferred flushing in iommu drivers Tom Murphy
2020-09-03 20:18 ` [PATCH V2 2/5] iommu: Add iommu_dma_free_cpu_cached_iovas function Tom Murphy
2020-09-09  0:45   ` Lu Baolu
2020-09-09  7:05     ` Christoph Hellwig
2020-09-12  2:55       ` Lu Baolu
2020-09-03 20:18 ` [PATCH V2 3/5] iommu: allow the dma-iommu api to use bounce buffers Tom Murphy
2020-09-09  1:34   ` Lu Baolu
2020-09-03 20:18 ` [PATCH V2 4/5] iommu/vt-d: Convert intel iommu driver to the iommu ops Tom Murphy
2020-09-09  1:59   ` Lu Baolu
2020-09-03 20:18 ` [PATCH V2 5/5] DO NOT MERGE: iommu: disable list appending in dma-iommu Tom Murphy
2020-09-07  7:00   ` Christoph Hellwig
2020-09-07 20:18     ` Tom Murphy
2020-09-08  5:36       ` Christoph Hellwig
2020-09-08  5:55         ` Christoph Hellwig
2020-09-08  6:04           ` Lu Baolu
2020-09-08  6:23             ` Christoph Hellwig
2020-09-08  9:07               ` Lu Baolu
2020-09-09  1:43               ` Lu Baolu [this message]
2020-09-09  7:06                 ` Christoph Hellwig
2020-09-12  3:13                   ` Lu Baolu
2020-09-04 10:03 ` [PATCH V2 0/5] Convert the intel iommu driver to the dma-iommu api Joerg Roedel

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