If there's no hard_limit set and domain uses VFIO we still must lock the guest memory (prerequisite from qemu). Hence, we should compute the amount to be locked from max_balloon. Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- src/qemu/qemu_hotplug.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c index 9727410..f028df6 100644 --- a/src/qemu/qemu_hotplug.c +++ b/src/qemu/qemu_hotplug.c @@ -1020,6 +1020,8 @@ int qemuDomainAttachHostPciDevice(virQEMUDriverPtr driver, if (hostdev->source.subsys.u.pci.backend == VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO) { + unsigned long long memKB; + if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DEVICE_VFIO_PCI)) { virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", _("VFIO PCI device assignment is not " @@ -1032,8 +1034,9 @@ int qemuDomainAttachHostPciDevice(virQEMUDriverPtr driver, * doesn't hurt to "change" the limit to the same value. */ vm->def->hostdevs[vm->def->nhostdevs++] = hostdev; - virProcessSetMaxMemLock(vm->pid, - vm->def->mem.hard_limit * 1024); + memKB = def->mem.hard_limit ? + def->mem.hard_limit : def->mem.max_balloon + 1024 * 1024; + virProcessSetMaxMemLock(vm->pid, memKB); vm->def->hostdevs[vm->def->nhostdevs--] = NULL; } -- 1.8.1.5