6.6-stable review patch. If anyone has any objections, please let me know.
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From: Mingcong Bai jeffbai@aosc.io
commit 2c8a7c66c90832432496616a9a3c07293f1364f3 upstream.
On the Lenovo ThinkPad X201, when Intel VT-d is enabled in the BIOS, the kernel boots with errors related to DMAR, the graphical interface appeared quite choppy, and the system resets erratically within a minute after it booted:
DMAR: DRHD: handling fault status reg 3 DMAR: [DMA Write NO_PASID] Request device [00:02.0] fault addr 0xb97ff000 [fault reason 0x05] PTE Write access is not set
Upon comparing boot logs with VT-d on/off, I found that the Intel Calpella quirk (`quirk_calpella_no_shadow_gtt()') correctly applied the igfx IOMMU disable/quirk correctly:
pci 0000:00:00.0: DMAR: BIOS has allocated no shadow GTT; disabling IOMMU for graphics
Whereas with VT-d on, it went into the "else" branch, which then triggered the DMAR handling fault above:
... else if (!disable_igfx_iommu) { /* we have to ensure the gfx device is idle before we flush */ pci_info(dev, "Disabling batched IOTLB flush on Ironlake\n"); iommu_set_dma_strict(); }
Now, this is not exactly scientific, but moving 0x0044 to quirk_iommu_igfx seems to have fixed the aforementioned issue. Running a few `git blame' runs on the function, I have found that the quirk was originally introduced as a fix specific to ThinkPad X201:
commit 9eecabcb9a92 ("intel-iommu: Abort IOMMU setup for igfx if BIOS gave no shadow GTT space")
Which was later revised twice to the "else" branch we saw above:
- 2011: commit 6fbcfb3e467a ("intel-iommu: Workaround IOTLB hang on Ironlake GPU") - 2024: commit ba00196ca41c ("iommu/vt-d: Decouple igfx_off from graphic identity mapping")
I'm uncertain whether further testings on this particular laptops were done in 2011 and (honestly I'm not sure) 2024, but I would be happy to do some distro-specific testing if that's what would be required to verify this patch.
P.S., I also see IDs 0x0040, 0x0062, and 0x006a listed under the same `quirk_calpella_no_shadow_gtt()' quirk, but I'm not sure how similar these chipsets are (if they share the same issue with VT-d or even, indeed, if this issue is specific to a bug in the Lenovo BIOS). With regards to 0x0062, it seems to be a Centrino wireless card, but not a chipset?
I have also listed a couple (distro and kernel) bug reports below as references (some of them are from 7-8 years ago!), as they seem to be similar issue found on different Westmere/Ironlake, Haswell, and Broadwell hardware setups.
Cc: stable@vger.kernel.org Fixes: 6fbcfb3e467a ("intel-iommu: Workaround IOTLB hang on Ironlake GPU") Fixes: ba00196ca41c ("iommu/vt-d: Decouple igfx_off from graphic identity mapping") Link: https://groups.google.com/g/qubes-users/c/4NP4goUds2c?pli=1 Link: https://bugs.archlinux.org/task/65362 Link: https://bbs.archlinux.org/viewtopic.php?id=230323 Reported-by: Wenhao Sun weiguangtwk@outlook.com Closes: https://bugzilla.kernel.org/show_bug.cgi?id=197029 Signed-off-by: Mingcong Bai jeffbai@aosc.io Link: https://lore.kernel.org/r/20250415133330.12528-1-jeffbai@aosc.io Signed-off-by: Lu Baolu baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iommu/intel/iommu.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -4855,6 +4855,9 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_I DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2e40, quirk_iommu_igfx); DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2e90, quirk_iommu_igfx);
+/* QM57/QS57 integrated gfx malfunctions with dmar */ +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x0044, quirk_iommu_igfx); + /* Broadwell igfx malfunctions with dmar */ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x1606, quirk_iommu_igfx); DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x160B, quirk_iommu_igfx); @@ -4932,7 +4935,6 @@ static void quirk_calpella_no_shadow_gtt } } DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x0040, quirk_calpella_no_shadow_gtt); -DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x0044, quirk_calpella_no_shadow_gtt); DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x0062, quirk_calpella_no_shadow_gtt); DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x006a, quirk_calpella_no_shadow_gtt);