On 2018-02-22 21:57, Bjorn Helgaas wrote: > On Mon, Jan 22, 2018 at 07:12:46AM +0100, Jan Kiszka wrote: >> From: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> >> >> PCI and PCIBIOS probing only scans devices at function number 0/8/16/... >> Subdevices (e.g. multiqueue) have function numbers which are not a >> multiple of 8. > > Suggested text: > > Per PCIe r4.0, sec 7.5.1.1.9, multi-function devices are required to > have a function 0. Therefore, Linux scans for devices at function 0 > (devfn 0/8/16/...) and only scans for other functions if function 0 > has its Multi-Function Device bit set or ARI or SR-IOV indicate > there are more functions. > > The Jailhouse hypervisor may pass individual functions of a > multi-function device to a guest without passing function 0, which > means a Linux guest won't find them. > > Change Linux PCI probing so it scans all function numbers when > running as a guest over Jailhouse. > > This is technically prohibited by the spec, so it is possible that > PCI devices without the Multi-Function Device bit set may have > unexpected behavior in response to this probe. > >> The simple hypervisor Jailhouse passes subdevices directly w/o providing >> a virtual PCI topology like KVM. As a consequence a PCI passthrough from >> Jailhouse to a guest will not be detected by Linux. >> >> Based on patch by Benedikt Spranger, adding Jailhouse probing to avoid >> changing the behavior in the absence of the hypervisor. >> >> CC: Benedikt Spranger <b.spranger@xxxxxxxxxxxxx> >> Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> > > With subject change to: > > PCI: Scan all functions when running over Jailhouse > > Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > Thanks, all suggestions picked up for next round. Jan -- Siemens AG, Corporate Technology, CT RDA IOT SES-DE Corporate Competence Center Embedded Linux _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
