[PATCH 0/5] iommu/vt-d: Fix crash dump failure caused by legacy DMA/IO

Li, ZhenHua zhen-hual at hp.com
Sun Nov 30 22:31:38 PST 2014


After I implement these two steps, there comes a new fault:

[1.594890] dmar: DRHD: handling fault status reg 2
[1.594894] dmar: INTR-REMAP: Request device [[41:00.0] fault index 4d
[1.594894] INTR-REMAP:[fault reason 34] Present field in the IRTE entry
is clear

It is caused by similar reason, so I will fix it like fixing the DMAR
faults: Do NOT disable and re-enable the interrupt remapping, try to
use data from old kernel.


On 11/17/2014 09:38 PM, Joerg Roedel wrote:
> On Fri, Nov 14, 2014 at 02:27:44PM +0800, Li, ZhenHua wrote:
>> I am working following  your directions:
>> 1.  If the VT-d driver finds the IOMMU enabled, it reuses its root entry
>> table, and do NOT disable-enable iommu. Other data will be copied.
>> 2. When a device driver issues the first dma_map command for a
>> device, we assign a new and empty page-table, thus removing all
>> mappings from the old kernel for the device.
>> Please let me know if I get something wrong.
> Yes, this sounds right. Happily waiting for patches :)
> 	Joerg

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