When a device has an upstream PCIE port, we can only use slot 0. Non-zero slots are invalid. This change ensures that we throw an error if the user tries to hotplug a device with an upstream PCIE port to a non-zero slot.
CC: jus...@redhat.com CC: imamm...@redhat.com Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2128929 Signed-off-by: Ani Sinha <anisi...@redhat.com> --- hw/pci/pci.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) changelog: v2: addressed issue with multifunction pcie root ports. Should allow hotplug on functions other than function 0. v3: improved commit message. v4: improve commit message and code comments further. Some more improvements might come in v5. No claims made here that this is the final one :-) diff --git a/hw/pci/pci.c b/hw/pci/pci.c index bf38905b7d..30ce6a78cb 100644 --- a/hw/pci/pci.c +++ b/hw/pci/pci.c @@ -64,6 +64,7 @@ bool pci_available = true; static char *pcibus_get_dev_path(DeviceState *dev); static char *pcibus_get_fw_dev_path(DeviceState *dev); static void pcibus_reset(BusState *qbus); +static bool pcie_has_upstream_port(PCIDevice *dev); static Property pci_props[] = { DEFINE_PROP_PCI_DEVFN("addr", PCIDevice, devfn, -1), @@ -1182,6 +1183,11 @@ static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, } else if (dev->hotplugged && !pci_is_vf(pci_dev) && pci_get_function_0(pci_dev)) { + /* + * populating function 0 triggers a bus scan from the guest that + * exposes other non-zero functions. Hence we need to ensure that + * function 0 wasn't added yet. + */ error_setg(errp, "PCI: slot %d function 0 already occupied by %s," " new func %s cannot be exposed to guest.", PCI_SLOT(pci_get_function_0(pci_dev)->devfn), @@ -1189,6 +1195,18 @@ static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, name); return NULL; + } else if (dev->hotplugged && + !pci_is_vf(pci_dev) && + pcie_has_upstream_port(pci_dev) && PCI_SLOT(devfn)) { + /* + * If the device has an upstream PCIE port, like a pcie root port, + * we only support functions on slot 0. + */ + error_setg(errp, "PCI: slot %d is not valid for %s," + " only functions on slot 0 is supported for devices" + " with an upstream PCIE port.", + PCI_SLOT(devfn), name); + return NULL; } pci_dev->devfn = devfn; -- 2.39.1
