On 25/07/19 12:03, Michael S. Tsirkin wrote: >> +#ifdef CONFIG_PCI >> + x86_platform.pci_scan_bus = kvm_pci_scan_bus; >> +#endif >> + >> if (!kvm_para_available()) >> return; >> > Shouldn't this happen after kvm_para_available?
Actually kvm_para_available() is not needed anymore, since this only runs after kvm_detect() has returned true. > In fact, let's add a CPU ID flag for this, so it's > easy to tell guest whether to scan extra buses. > What do you say? I think it would make it much harder to deploy this, since it relies on having new userspace and new machine types. This patch is basically a reflection of the status quo, which is that there are generally no "hidden" buses on commonly-used KVM userspaces, and even in the weird configurations that have them there is always something at devfn=0. (On real hardware, the only such hidden bus is e.g. 0x7f/0xff, which have a bunch of QPI and MCH-related devices. This is not something you'd have in a virtual machine). Paolo
