This resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1035490 virProcessSetMaxMemLock() (which is a wrapper over prlimit(3)) expects the memory size in bytes, but libvirt's domain definition (which was being used by qemuDomainAttachHostPciDevice()) stores all memory tuning parameters in KiB. This was being accounted for when setting MaxMemLock at domain startup time (so cold-plugged devices would work), but not for hotplug. This patch simplifies the few lines that call virProcessSetMemMaxLock(), and multiply the amount * 1024 so that we're locking the correct amount of memory. What remains a mystery to me is why hot-plug of a managed='no' device would succeed (at least on my system) while managed='yes' would fail. I guess in one case the memory was coincidentally already resident and in the other it wasn't. --- src/qemu/qemu_hotplug.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c index a375b6c..4a2c5ce 100644 --- a/src/qemu/qemu_hotplug.c +++ b/src/qemu/qemu_hotplug.c @@ -1155,6 +1155,7 @@ qemuDomainAttachHostPciDevice(virQEMUDriverPtr driver, bool teardowncgroup = false; bool teardownlabel = false; int backend = hostdev->source.subsys.u.pci.backend; + unsigned long long memKB; if (VIR_REALLOC_N(vm->def->hostdevs, vm->def->nhostdevs + 1) < 0) return -1; @@ -1172,16 +1173,18 @@ qemuDomainAttachHostPciDevice(virQEMUDriverPtr driver, goto error; } - /* VFIO requires all of the guest's memory to be locked resident. - * In this case, the guest's memory may already be locked, but it + /* VFIO requires all of the guest's memory to be locked + * resident (plus an additional 1GiB to cover IO space). During + * hotplug, the guest's memory may already be locked, but it * doesn't hurt to "change" the limit to the same value. + * NB: the domain's memory tuning parameters are stored as + * Kibibytes, but virProcessSetMaxMemLock expects the value in + * bytes. */ - if (vm->def->mem.hard_limit) - virProcessSetMaxMemLock(vm->pid, vm->def->mem.hard_limit); - else - virProcessSetMaxMemLock(vm->pid, - vm->def->mem.max_balloon + (1024 * 1024)); - + memKB = vm->def->mem.hard_limit + ? vm->def->mem.hard_limit + : vm->def->mem.max_balloon + (1024 * 1024); + virProcessSetMaxMemLock(vm->pid, memKB * 1024); break; case VIR_DOMAIN_HOSTDEV_PCI_BACKEND_DEFAULT: -- 1.8.3.1

This resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1045002 If a domain has an <interface type='hostdev'> or an <interface type='network'> where the network itself is a pool of hostdev devices, then libvirt will internally keep that device on both the interface list *and* the hostdev list for the domain. One of the places this comes in handy is when a new device is being added and libvirt wants to find a unique "alias" name for it - it just scans through the hostdev array and makes sure it picks a name that doesn't match the alias of any device in that array. However, when libvirtd was restarted, if there was an <interface type='network'> with the network being a hostdev pool, the device would not be added to the reconstructed internal hostdev array, so its alias would not be found during a scan of the hostdev array, thus attempts to add a new hostdev (or <interface type='hostdev'> or <interface type='network'>) would result in a message like this: internal error: unable to execute QEMU command 'device_add': Duplicate ID 'hostdev0' for device This patch simply fixes the existing code in the domain XML parser that fixes up the hostdev array in the case of <interface type='hostdev'> to do the same thing in the case of <interface type='network'> with a hostdev network. This bug has existed since the very first addition of hostdev networks to libvirt (0.10.0). --- src/conf/domain_conf.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index 0079234..583ea02 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -12101,9 +12101,12 @@ virDomainDefParseXML(xmlDocPtr xml, def->nets[def->nnets++] = net; - /* <interface type='hostdev'> must also be in the hostdevs array */ - if (net->type == VIR_DOMAIN_NET_TYPE_HOSTDEV && - virDomainHostdevInsert(def, &net->data.hostdev.def) < 0) { + /* <interface type='hostdev'> (and <interface type='net'> + * where the actual network type is already known to be + * hostdev) must also be in the hostdevs array. + */ + if (virDomainNetGetActualType(net) == VIR_DOMAIN_NET_TYPE_HOSTDEV && + virDomainHostdevInsert(def, virDomainNetGetActualHostdev(net)) < 0) { goto error; } } -- 1.8.3.1