Hi Davidlohr, Thanks for the information! According to lspci output, device 0000:02:00.2 is HP ILO controller, device 0000:03:00.0 is RAID controller. Both ILO and RAID controllers need to access reserved memory range [0x7f61e000 - 0x7f61ffff] in physical mode. According to dmesg output, BIOS has reserved memory and IOMMU has setup 1:1 mapping for ILO and RAID controller to access this range. Related log messages as below: BIOS-e820: [mem 0x000000007f61d000-0x000000008fffffff] reserved IOMMU: Setting RMRR: IOMMU: Setting identity map for device 0000:03:00.0 [0x7f61e000 - 0x7f61ffff] IOMMU: Setting identity map for device 0000:02:00.0 [0x7f61e000 - 0x7f61ffff] IOMMU: Setting identity map for device 0000:02:00.2 [0x7f61e000 - 0x7f61ffff] From the screenshot, device 0000:02:00.2 fails to access memory address 0x7f61e000. That indicates IOMMU driver fails to setup 1:1 mapping for Reserved Memory Range for ILO controller. So could you please help to check whether you could observe boot messages like "IOMMU: Setting identity map for device 0000:02:00.2 [0x7f61e000 - 0x7f61ffff]" with the failure kernel image? It would be great if boot messages could be saved when failing to boot, so we could get more information from log. BTW, I have double checked related code, and still can't find a reliable explanation for the regression:( Thanks! Gerry On 2014/4/11 0:19, Davidlohr Bueso wrote: > On Thu, 2014-04-10 at 08:46 +0000, Woodhouse, David wrote: >> On Thu, 2014-04-10 at 09:15 +0200, Joerg Roedel wrote: >>> [+ David, VT-d maintainer ] >>> >>> Jiang, David, can you please have a look into this issue? >>> >> >>>>>>>>>>> DMAR:[fault reason 02] Present bit in context entry is clear >>>>>>>>>>> dmar: DRHD: handling fault status reg 602 >>>>>>>>>>> dmar: DMAR:[DMA Read] Request device [02:00.0] fault addr 7f61e000 >> >> That "Present bit in context entry is clear" fault means that we have >> not set up *any* mappings for this PCI device… on this IOMMU. >> >>>> Yes, specifically (finally done bisecting): >>>> >>>> commit 2e45528930388658603ea24d49cf52867b928d3e >>>> Author: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx> >>>> Date: Wed Feb 19 14:07:36 2014 +0800 >>>> >>>> iommu/vt-d: Unify the way to process DMAR device scope array >> >> This commit is about how we decide which IOMMU a given PCI device is >> attached to. >> >> Thus, my first guess would be that we are quite happily setting up the >> requested DMA maps on the *wrong* IOMMU, and then taking faults when the >> device actually tries to do DMA. >> >> However, I'm not 100% convinced of that. The fault address looks >> suspiciously like a true physical address, not a virtual bus address of >> the type that we'd normally allocate for a dma_map_* operation. Those >> would start at 0xfffff000 and work downwards, typically. >> >> Do you have 'iommu=pt' on the kernel command line? > > No. > >> Can I see the full >> dmesg as this system boots, and also a copy of the DMAR table? > > Attaching a dmesg from one of the kernels that boots. It doesn't appear > to have much of the related information... is there any debug config > option I can enable that might give you more data? > -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
