pci: fix 'io hints' capability for RedHat PCI bridges

Commit ec6cb17f (pci: enable RedHat PCI bridges to reserve additional
                 resources on PCI init)
added a new vendor specific PCI capability for RedHat PCI bridges
allowing them to reserve additional buses and/or IO/MEM space.

When adding the IO hints PCI capability to the pcie-root-port
without specifying a value for bus reservation, the subordinate bus
computation is wrong and the guest kernel gets messed up.

Fix it by returning to prev code if the value for bus
reservation is not set.

Removed also a wrong debug print "PCI: invalid QEMU resource reserve
cap offset" which appears if the 'IO hints' capability is not present.

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>

diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
index 7f0e439de0595c831257ac609ef654b9cc7a6894..3a2f7479848fbe0f292eb2c1277f8210da4befdc 100644 (file)
--- a/src/fw/pciinit.c
+++ b/src/fw/pciinit.c
@@ -540,8 +540,6 @@ static u8 pci_find_resource_reserve_capability(u16 bdf)
                 dprintf(1, "PCI: QEMU resource reserve cap length %d is invalid\n",
                         cap_len);
             }
-        } else {
-            dprintf(1, "PCI: invalid QEMU resource reserve cap offset\n");
         }
         return cap;
     } else {
@@ -619,13 +617,11 @@ pci_bios_init_bus_rec(int bus, u8 *pci_bus)
                                 res_bus);
                         res_bus = 0;
                     }
-                }
-                if (secbus + res_bus > *pci_bus) {
-                    dprintf(1, "PCI: QEMU resource reserve cap: bus = %u\n",
-                            res_bus);
-                    res_bus = secbus + res_bus;
-                } else {
-                    res_bus = *pci_bus;
+                    if (secbus + res_bus > *pci_bus) {
+                        dprintf(1, "PCI: QEMU resource reserve cap: bus = %u\n",
+                                res_bus);
+                        res_bus = secbus + res_bus;
+                    }
                 }
             }
             dprintf(1, "PCI: subordinate bus = 0x%x -> 0x%x\n",