[+cc Alex, add a subject] On Fri, Nov 14, 2014 at 6:49 PM, Allan, Bruce W <bruce.w.allan@xxxxxxxxx> wrote: > Let's try this again as plain text... > > For a PCIe device with SR-IOV support enabled (e.g. the PF device ID is 0xf001 at 0000:07:00.0 and the 16 VFs have device ID 0xf002 at 0000:07:01.0 through 0000:07:02.7), if the hardware attempts a DMA read/write of memory that was mapped by the PF devfn but instead uses a requester id of one of the VF devfns (enabled but not yet assigned to a VM) it fails and generates log messages similar to: > > [ 416.800881] dmar: DRHD: handling fault status reg 2 > [ 416.800887] dmar: DMAR:[DMA Read] Request device [07:02.2] fault addr ffff0000 > DMAR:[fault reason 02] Present bit in context entry is clear > > Shouldn't a DMA alias quirk that sets the PCI_DEV_FLAGS_DMA_ALIAS_DEVFN flag and dma_alias_devfn to the PF devfn for all VF devfns work-around this issue, or am I misunderstanding what a DMA alias quirk is supposed to do? If a DMA alias quirk cannot resolve this, what is the most appropriate way to handle this? > > Thanks, > Bruce. > -- > 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 -- 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
