Re: [RESEND PATCH v5 5/5] hw/pci: ensure PCIE devices are plugged into only slot 0 of PCIE port

[Michael S. Tsirkin]

On Tue, Jun 27, 2023 at 03:23:04PM +0530, Ani Sinha wrote:
> 
> 
> > On 27-Jun-2023, at 2:32 PM, Igor Mammedov <imammedo@redhat.com> wrote:
> > 
> > On Mon, 26 Jun 2023 21:42:44 +0530
> > Ani Sinha <anisinha@redhat.com> wrote:
> > 
> >> PCI Express ports only have one slot, so PCI Express devices can only be
> >> plugged into slot 0 on a PCIE port. Enforce it.
> > 
> > btw, previously you mentioned ARI.
> > So if we turn it on, wouldn't this patch actually become regression?
> 
> If ARI breaks this, it will break other areas in QEMU too, ex anywhere 
> pci_get_function_0() is used.

We will just fix pci_get_function_0.

> Regardless, I think at least the tests are worth fixing, particularly the 
> mess with hd-geo-test.

ok

> > 
> >> 
> >> CC: jusual@redhat.com
> >> CC: imammedo@redhat.com
> >> Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2128929
> >> Signed-off-by: Ani Sinha <anisinha@redhat.com>
> >> Reviewed-by: Julia Suvorova <jusual@redhat.com>
> >> ---
> >> hw/pci/pci.c | 6 ++++++
> >> 1 file changed, 6 insertions(+)
> >> 
> >> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> >> index bf38905b7d..426af133b0 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),
> >> @@ -1189,6 +1190,11 @@ static PCIDevice *do_pci_register_device(PCIDevice 
> >> *pci_dev,
> >>                    name);
> >> 
> >>        return NULL;
> >> +    } else if (pcie_has_upstream_port(pci_dev) && PCI_SLOT(devfn)) {
> >> +        error_setg(errp, "PCI: slot %d is not valid for %s,"
> >> +                   " parent device only allows plugging into slot 0.",
> >> +                   PCI_SLOT(devfn), name);
> >> +        return NULL;
> >>     }
> >> 
> >>     pci_dev->devfn = devfn;
> >