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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