Libvirt BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1175397 QEMU BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1170093 In qemu there are two interesting arguments: 1) -numa to create a guest NUMA node 2) -object memory-backend-{ram,file} to tell qemu which memory region on which host's NUMA node it should allocate the guest memory from. Combining these two together we can instruct qemu to create a guest NUMA node that is tied to a host NUMA node. And it works just fine. However, depending on machine type used, there might be some issued during migration when OVMF is enabled (see QEMU BZ). While this truly is a QEMU bug, we can help avoiding it. The problem lies within the memory backend objects somewhere. Having said that, fix on our side consists on putting those objects on the command line if and only if needed. For instance, while previously we would construct this (in all ways correct) command line: -object memory-backend-ram,size=256M,id=ram-node0 \ -numa node,nodeid=0,cpus=0,memdev=ram-node0 now we create just: -numa node,nodeid=0,cpus=0,mem=256 because the backend object is obviously not tied to any specific host NUMA node. Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- src/qemu/qemu_command.c | 16 +++++++++------- .../qemuxml2argvdata/qemuxml2argv-hugepages-pages3.args | 3 +-- .../qemuxml2argv-numatune-memnode-no-memory.args | 3 +-- 3 files changed, 11 insertions(+), 11 deletions(-) diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c index 11e7cff..d5679de 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -6660,6 +6660,7 @@ qemuBuildNumaArgStr(virQEMUDriverConfigPtr cfg, } for (i = 0; i < def->cpu->ncells; i++) { + virDomainHugePagePtr hugepage = NULL; unsigned long long cellmem = VIR_DIV_UP(def->cpu->cells[i].mem, 1024); def->cpu->cells[i].mem = cellmem * 1024; virMemAccess memAccess = def->cpu->cells[i].memAccess; @@ -6681,7 +6682,6 @@ qemuBuildNumaArgStr(virQEMUDriverConfigPtr cfg, if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_MEMORY_RAM) || virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_MEMORY_FILE)) { virDomainNumatuneMemMode mode; - virDomainHugePagePtr hugepage = NULL; const char *policy = NULL; mode = virDomainNumatuneGetMode(def->numatune, i); @@ -6798,8 +6798,12 @@ qemuBuildNumaArgStr(virQEMUDriverConfigPtr cfg, virBufferAsprintf(&buf, ",policy=%s", policy); } - virCommandAddArg(cmd, "-object"); - virCommandAddArgBuffer(cmd, &buf); + if (hugepage || nodemask) { + virCommandAddArg(cmd, "-object"); + virCommandAddArgBuffer(cmd, &buf); + } else { + virBufferFreeAndReset(&buf); + } } else { if (memAccess) { virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", @@ -6819,12 +6823,10 @@ qemuBuildNumaArgStr(virQEMUDriverConfigPtr cfg, virBufferAdd(&buf, tmpmask, -1); } - if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_MEMORY_RAM) || - virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_MEMORY_FILE)) { + if (hugepage || nodemask) virBufferAsprintf(&buf, ",memdev=ram-node%zu", i); - } else { + else virBufferAsprintf(&buf, ",mem=%llu", cellmem); - } virCommandAddArgBuffer(cmd, &buf); } diff --git a/tests/qemuxml2argvdata/qemuxml2argv-hugepages-pages3.args b/tests/qemuxml2argvdata/qemuxml2argv-hugepages-pages3.args index 27b3f8e..f81947e 100644 --- a/tests/qemuxml2argvdata/qemuxml2argv-hugepages-pages3.args +++ b/tests/qemuxml2argvdata/qemuxml2argv-hugepages-pages3.args @@ -1,7 +1,6 @@ LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test QEMU_AUDIO_DRV=none \ /usr/bin/qemu -S -M pc -m 1024 -smp 2 \ --object memory-backend-ram,size=256M,id=ram-node0 \ --numa node,nodeid=0,cpus=0,memdev=ram-node0 \ +-numa node,nodeid=0,cpus=0,mem=256 \ -object memory-backend-file,prealloc=yes,\ mem-path=/dev/hugepages1G/libvirt/qemu,size=768M,id=ram-node1 \ -numa node,nodeid=1,cpus=1,memdev=ram-node1 \ diff --git a/tests/qemuxml2argvdata/qemuxml2argv-numatune-memnode-no-memory.args b/tests/qemuxml2argvdata/qemuxml2argv-numatune-memnode-no-memory.args index b0e274c..2addf97 100644 --- a/tests/qemuxml2argvdata/qemuxml2argv-numatune-memnode-no-memory.args +++ b/tests/qemuxml2argvdata/qemuxml2argv-numatune-memnode-no-memory.args @@ -2,7 +2,6 @@ LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test QEMU_AUDIO_DRV=none \ /usr/bin/kvm -S -M pc -m 64 -smp 2 \ -object memory-backend-ram,size=32M,id=ram-node0,host-nodes=3,policy=preferred \ -numa node,nodeid=0,cpus=0,memdev=ram-node0 \ --object memory-backend-ram,size=32M,id=ram-node1 \ --numa node,nodeid=1,cpus=1,memdev=ram-node1 \ +-numa node,nodeid=1,cpus=1,mem=32 \ -nographic -monitor unix:/tmp/test-monitor,server,nowait \ -no-acpi -boot c -usb -net none -serial none -parallel none -- 2.0.4