Re: [libvirt] [PATCH 4/6] qemu: Reduce memlock limit after detaching hostdev

We increase the limit before plugging in a PCI hostdev or a memory module because some memory might need to be locked due to eg. VFIO. Of course we should do the opposite after unplugging a device: this was already the case for memory modules, but not for hostdevs. --- src/qemu/qemu_hotplug.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c index 0bd88ce..2a16f89 100644 --- a/src/qemu/qemu_hotplug.c +++ b/src/qemu/qemu_hotplug.c @@ -3084,6 +3084,14 @@ qemuDomainRemoveHostDevice(virQEMUDriverPtr driver, networkReleaseActualDevice(vm->def, net); virDomainNetDefFree(net); } + + /* QEMU might no longer need to lock as much memory, eg. we just detached + * a VFIO device, so adjust the limit here */ + if (qemuDomainRequiresMlock(vm->def)) + if (virProcessSetMaxMemLock(vm->pid, + qemuDomainGetMlockLimitBytes(vm->def)) < 0) + VIR_WARN("Failed to adjust locked memory limit"); +