[Qemu-stable] [PATCH 37/81] pci: fix error message for express slots

[Michael Roth]

From: "Michael S. Tsirkin" <address@hidden>

PCI Express downstream slot has a single PCI slot
behind it, using PCI_DEVFN(PCI_SLOT(devfn), 0)
does not give you function 0 in cases such as ARI
as well as some error cases.

This is exactly what we are hitting:
   $ qemu-system-x86_64 -machine q35 -readconfig docs/q35-chipset.cfg
-monitor stdio
   (qemu) device_add e1000e,bus=ich9-pcie-port-4,addr=00
   (qemu) device_add e1000e,bus=ich9-pcie-port-4,addr=08
   Segmentation fault (core dumped)

The fix is to use the pci_get_function_0 API.

Cc: address@hidden
Signed-off-by: Michael S. Tsirkin <address@hidden>
Reported-by: Eduardo Habkost <address@hidden>
Tested-by: Cao jin <address@hidden>
Tested-by: Eduardo Habkost <address@hidden>
Reviewed-by: Eduardo Habkost <address@hidden>
(cherry picked from commit d93ddfb1f8fb72a7c175a8cf1028c639f769d105)
Signed-off-by: Michael Roth <address@hidden>
---
 hw/pci/pci.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 24fae16..637d545 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -982,8 +982,8 @@ static PCIDevice *do_pci_register_device(PCIDevice 
*pci_dev, PCIBus *bus,
                pci_get_function_0(pci_dev)) {
         error_setg(errp, "PCI: slot %d function 0 already ocuppied by %s,"
                    " new func %s cannot be exposed to guest.",
-                   PCI_SLOT(devfn),
-                   bus->devices[PCI_DEVFN(PCI_SLOT(devfn), 0)]->name,
+                   PCI_SLOT(pci_get_function_0(pci_dev)->devfn),
+                   pci_get_function_0(pci_dev)->name,
                    name);
 
        return NULL;
-- 
2.7.4