PCI: Scan all functions when running over Jailhouse
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. Originally-by: NBenedikt Spranger <b.spranger@linutronix.de> Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com> Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com> Acked-by: NBjorn Helgaas <bhelgaas@google.com> Cc: jailhouse-dev@googlegroups.com Cc: Benedikt Spranger <b.spranger@linutronix.de> Cc: linux-pci@vger.kernel.org Cc: virtualization@lists.linux-foundation.org Link: https://lkml.kernel.org/r/06e279b2a3e06cf6689ab3975f8ab592bba02362.1520408357.git.jan.kiszka@siemens.com
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