On Fri, Feb 25, 2022 at 11:12:59AM +0100, Gerd Hoffmann wrote:
> Hi,
>
> > pcie_cap_slot_post_load()
> > -> pcie_cap_update_power()
> > -> pcie_set_power_device()
> > -> pci_set_power()
> > -> pci_update_mappings()
>
> > Fix it by honoring PCI_EXP_SLTCAP_PCP and updating power status
> > only if capability is enabled.
>
> > diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
> > index d7d73a31e4..2339729a7c 100644
> > --- a/hw/pci/pcie.c
> > +++ b/hw/pci/pcie.c
> > @@ -383,10 +383,9 @@ static void pcie_cap_update_power(PCIDevice
> > *hotplug_dev)
> >
> > if (sltcap & PCI_EXP_SLTCAP_PCP) {
> > power = (sltctl & PCI_EXP_SLTCTL_PCC) == PCI_EXP_SLTCTL_PWR_ON;
> > + pci_for_each_device(sec_bus, pci_bus_num(sec_bus),
> > + pcie_set_power_device, &power);
> > }
> > -
> > - pci_for_each_device(sec_bus, pci_bus_num(sec_bus),
> > - pcie_set_power_device, &power);
> > }
>
> The change makes sense, although I don't see how that changes qemu
> behavior.
>
> 'power' defaults to true, so when SLTCAP_PCP is off it should never
> ever try to power off the devices. And pci_set_power() should figure
> the state didn't change and instantly return without touching the
> device.
>
> take care,
> Gerd
And making sure power is actually up might be a bit cleaner just in
case down the road we start plugging devices in a powered off state.
--
MST
