https://bugzilla.kernel.org/show_bug.cgi?id=82761 --- Comment #6 from Alex Williamson <alex.williamson@xxxxxxxxxx> --- Ok, then it's probably not a result of the PCIe-to-PCI bridge since 05:00.0 is the correct requester ID for all the devices behind the bridge. Unfortunately that means that the problem may not be fixable. We're only seeing reads to a single address, which may mean the NIC is using that read to synchronize transaction ordering, ex. using a DMA read to flush a DMA write from the device. If the NIC driver has visibility of this address, then it could attempt to do a coherent mapping for the device(s) to avoid the fault. If it doesn't, then these NICs may simply be incompatible with the IOMMU. Are these 3 separate NICs plugged into PCI slots on the motherboard or is this a single triple-port card with embedded PCIe-to-PCI bridge? You might be able to run the IOMMU in passthrough mode with iommu=pt r8169.use_dac=1, but note the warning in modinfo "use_dac:Enable PCI DAC. Unsafe on 32 bit PCI slot." Unfortunately if you don't enable use_dac, then intel_iommu will ignore the passthrough option for these devices. Also note that this problem has nothing to do with Virtualization/KVM. Drivers/Network or perhaps Drivers/PCI would be a more appropriate classification. -- You are receiving this mail because: You are watching the assignee of the bug. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
