[libvirt] [PATCH 1/3] qemu: Tweak auto adding PCI bridge controller when extending default PCI bus

In case we find out, there are more PCI devices to be connected than there are available slots on the default PCI bus, we automatically add a new bus and a related PCI bridge controller as well. As there are no free slots left on the default PCI bus, PCI bridge controller gets a free slot on a newly created PCI bus which causes qemu to refuse to start the guest. This fix introduces a new function qemuDomainPCIBusFullyReserved which is checked right before we possibly try to reserve a slot for PCI bridge controller. Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1132900 --- src/qemu/qemu_command.c | 24 +++++++++++++++++++++--- 1 file changed, 21 insertions(+), 3 deletions(-) diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c index 3346e95..06def5f 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -1445,6 +1445,18 @@ qemuDomainSupportsPCI(virDomainDefPtr def) return false; } +static bool +qemuDomainPCIBusFullyReserved(virDomainPCIAddressBusPtr bus) +{ + size_t i; + + for (i = bus->minSlot; i <= bus->maxSlot; i++) + if (!bus->slots[i]) + return false; + + return true; +} + int qemuDomainAssignPCIAddresses(virDomainDefPtr def, virQEMUCapsPtr qemuCaps, @@ -1479,9 +1491,15 @@ qemuDomainAssignPCIAddresses(virDomainDefPtr def, goto cleanup; if (qemuAssignDevicePCISlots(def, qemuCaps, addrs) < 0) goto cleanup; - /* Reserve 1 extra slot for a (potential) bridge */ - if (virDomainPCIAddressReserveNextSlot(addrs, &info, flags) < 0) - goto cleanup; + + for (i = 0; i < addrs->nbuses; i++) { + if (!qemuDomainPCIBusFullyReserved(&addrs->buses[i])) { + + /* Reserve 1 extra slot for a (potential) bridge */ + if (virDomainPCIAddressReserveNextSlot(addrs, &info, flags) < 0) + goto cleanup; + } + } for (i = 1; i < addrs->nbuses; i++) { virDomainPCIAddressBusPtr bus = &addrs->buses[i]; -- 1.9.3