When hotunplugging a PCI function we'll branch out the logic in two cases, function zero and non-zero. If non-zero, we'll call spapr_drc_detach() and nothing else. If it's function zero, we'll loop it once between all the functions in the slot to call spapr_drc_detach() on them, and afterwards we'll do another backwards loop where we'll signal the event to the guest.
We can simplify this logic. We can ignore all the DRC handling for non-zero functions, since we'll end up doing that regardless when unplugging function zero. And for function zero, everything can be done in a single loop, since tt doesn't matter if we end up marking the function DRCs as unplug pending in backwards order or not, as long as we call spapr_drc_detach() before issuing the hotunplug event to the guest. This will also avoid a possible scenario where the user starts to hotunplug the slot, starting with a non-zero function, and then delays/forgets to hotunplug function zero afterwards. This would keep the function DRC marked as unplug requested indefinitely. Signed-off-by: Daniel Henrique Barboza <danielhb...@gmail.com> --- hw/ppc/spapr_pci.c | 44 ++++++++++++++++---------------------------- 1 file changed, 16 insertions(+), 28 deletions(-) diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c index f1c7479816..1791d98a49 100644 --- a/hw/ppc/spapr_pci.c +++ b/hw/ppc/spapr_pci.c @@ -1709,38 +1709,26 @@ static void spapr_pci_unplug_request(HotplugHandler *plug_handler, return; } - /* ensure any other present functions are pending unplug */ - if (PCI_FUNC(pdev->devfn) == 0) { - for (i = 1; i < 8; i++) { - func_drc = drc_from_devfn(phb, chassis, PCI_DEVFN(slotnr, i)); - func_drck = SPAPR_DR_CONNECTOR_GET_CLASS(func_drc); - state = func_drck->dr_entity_sense(func_drc); - if (state == SPAPR_DR_ENTITY_SENSE_PRESENT - && !spapr_drc_unplug_requested(func_drc)) { - /* - * Attempting to remove function 0 of a multifunction - * device will will cascade into removing all child - * functions, even if their unplug weren't requested - * beforehand. - */ - spapr_drc_detach(func_drc); - } - } + /* + * The hotunplug itself will occur when unplugging function 0, + * regardless of marking any other functions DRCs as pending + * unplug beforehand (since 02a1536eee33). + */ + if (PCI_FUNC(pdev->devfn) != 0) { + return; } - spapr_drc_detach(drc); + for (i = 7; i >= 0; i--) { + func_drc = drc_from_devfn(phb, chassis, PCI_DEVFN(slotnr, i)); + func_drck = SPAPR_DR_CONNECTOR_GET_CLASS(func_drc); + state = func_drck->dr_entity_sense(func_drc); - /* if this isn't func 0, defer unplug event. otherwise signal removal - * for all present functions - */ - if (PCI_FUNC(pdev->devfn) == 0) { - for (i = 7; i >= 0; i--) { - func_drc = drc_from_devfn(phb, chassis, PCI_DEVFN(slotnr, i)); - func_drck = SPAPR_DR_CONNECTOR_GET_CLASS(func_drc); - state = func_drck->dr_entity_sense(func_drc); - if (state == SPAPR_DR_ENTITY_SENSE_PRESENT) { - spapr_hotplug_req_remove_by_index(func_drc); + if (state == SPAPR_DR_ENTITY_SENSE_PRESENT) { + /* Mark the DRC as requested unplug if needed. */ + if (!spapr_drc_unplug_requested(func_drc)) { + spapr_drc_detach(func_drc); } + spapr_hotplug_req_remove_by_index(func_drc); } } } -- 2.29.2