2.6.28-stable review patch. If anyone has any objections, please let us know. ------------------ From: David Woodhouse commit ca77fde8e62cecb2c0769052228d15b901367af8 upstream. This is the cause of the DMA faults and disk corruption that people have been seeing. Some chipsets neglect to report the RWBF "capability" -- the flag which says that we need to flush the chipset write-buffer when changing the DMA page tables, to ensure that the change is visible to the IOMMU. Override that bit on the affected chipsets, and everything is happy again. Thanks to Chris and Bhavesh and others for helping to debug. Signed-off-by: David Woodhouse Tested-by: Chris Wright Reviewed-by: Bhavesh Davda Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- drivers/pci/intel-iommu.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) --- a/drivers/pci/intel-iommu.c +++ b/drivers/pci/intel-iommu.c @@ -506,7 +506,7 @@ static void iommu_flush_write_buffer(str u32 val; unsigned long flag; - if (!cap_rwbf(iommu->cap)) + if (!rwbf_quirk && !cap_rwbf(iommu->cap)) return; val = iommu->gcmd | DMA_GCMD_WBF; @@ -1315,6 +1315,8 @@ static void domain_remove_dev_info(struc spin_unlock_irqrestore(&device_domain_lock, flags); } +static int rwbf_quirk = 0; + /* * find_domain * Note: we use struct pci_dev->dev.archdata.iommu stores the info @@ -2436,3 +2438,13 @@ u64 intel_iommu_iova_to_pfn(struct dmar_ return pfn >> VTD_PAGE_SHIFT; } EXPORT_SYMBOL_GPL(intel_iommu_iova_to_pfn); + +static void __devinit quirk_iommu_rwbf(struct pci_dev *dev) +{ + /* Mobile 4 Series Chipset neglects to set RWBF capability, + but needs it */ + printk(KERN_INFO "DMAR: Forcing write-buffer flush capability\n"); + rwbf_quirk = 1; +} + +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2a40, quirk_iommu_rwbf); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/