https://bugzilla.kernel.org/show_bug.cgi?id=81841 --- Comment #9 from Alex Williamson <alex.williamson@xxxxxxxxxx> --- (In reply to Marti Raudsepp from comment #8) > (In reply to Alex Williamson from comment #7) > > > There are some proposed workarounds on the web > > None of these remotely address the issue. > > I see. This page claims so: http://www.ovirt.org/Features/hostdev_passthrough Sorry, it's wrong. > > there are quirks for the following AMD southbridge components > > Nope, mine are 1022:780b, 1022:780c, 1022:780d, 1022:780e, 1022:780f, > 1022:7809 > > > If your bridge does not match these, then AMD will need to confirm whether > > isolation is provided between your devices. > > How would I go about confirming that? What are the chances that they care, > and provide accurate information to a random person? AMD would need to confirm it. IOMMU groups are based on hardware advertised isolation via the PCIe ACS capability. Without this, or a device specific quirk to take its place, IOMMU groups must assume that peer-to-peer between functions of a multi-function device is possible and therefore that the devices are not isolated. Chances are that this new chipset in your system is taking the exact same ASICs that were deemed not to do peer-to-peer on previous chipsets, but we need that confirmation from AMD. Alex Deucher (see MAINTAINERS) may have contacts available that can make that statement. > > There is an ACS override patch > > I already ran across it... > https://bugzilla.redhat.com/show_bug.cgi?id=1113399 > Would I be any worse off using this, compared to the old kvm pci-assign > method? I think the path forward is to get confirmation from AMD that these function are isolated from each other and add quirks to the kernel. Then you won't have the device dependencies in vfio-pci. The override patch allows you to do that with just a kernel boot parameter. There's no gurantee that pci-assign will ever be fixed since it's being phased out. -- 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
