On 7/10/21 12:47 AM, Ville Syrjala wrote:
From: Ville Syrjälä <ville.syrj...@linux.intel.com>While running "gem_exec_big --r single" from igt-gpu-tools on Geminilake as soon as a 2M mapping is made I tend to get a DMAR write fault. Strangely the faulting address is always a 4K page and usually very far away from the 2M page that got mapped. But if no 2M mappings get used I can't reproduce the fault. I also tried to dump the PTE for the faulting address but it actually looks correct to me (ie. definitely seems to have the write bit set): DMAR: DRHD: handling fault status reg 2 DMAR: [DMA Write] Request device [00:02.0] PASID ffffffff fault addr 7fa8a78000 [fault reason 05] PTE Write access is not set DMAR: fault 7fa8a78000 (level=1) PTE = 149efc003 So not really sure what's going on and this might just be full on duct tape, but it seems to work here. The machine has now survived a whole day running that test whereas with superpage enabled it fails in less than a minute usually. TODO: might be nice to disable superpage only for the igfx iommu instead of both iommus
If all these quirks are about igfx dedicated iommu's, I would suggest to disable superpage only for the igfx ones. Best regards, baolu
TODO: would be nice to use the macros from include/drm/i915_pciids.h, but can't do that with DECLARE_PCI_FIXUP_HEADER() Cc: David Woodhouse <dw...@infradead.org> Cc: Lu Baolu <baolu...@linux.intel.com> Cc: iommu@lists.linux-foundation.org Signed-off-by: Ville Syrjälä <ville.syrj...@linux.intel.com> --- drivers/iommu/intel/iommu.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 19c7888cbb86..4fff2c9c86af 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -5617,6 +5617,16 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x1632, quirk_iommu_igfx); DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x163A, quirk_iommu_igfx); DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x163D, quirk_iommu_igfx);+static void quirk_iommu_nosp(struct pci_dev *dev)+{ + pci_info(dev, "Disabling IOMMU superpage for graphics on this chipset\n"); + intel_iommu_superpage = 0; +} + +/* Geminilake igfx appears to have issues with superpage */ +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x3184, quirk_iommu_nosp); +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x3185, quirk_iommu_nosp); + static void quirk_iommu_rwbf(struct pci_dev *dev) { if (risky_device(dev))
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