We possibly populate empty nodes where memory isn't included and might be hot added at late time. The FDT memory nodes can't be created due to conflicts on their names if multiple empty nodes are specified. For example, the VM fails to start with the following error messages.
/home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \ -accel kvm -machine virt,gic-version=host \ -cpu host -smp 4,sockets=2,cores=2,threads=1 -m 1024M,maxmem=64G \ -object memory-backend-ram,id=mem0,size=512M \ -object memory-backend-ram,id=mem1,size=512M \ -numa node,nodeid=0,cpus=0-1,memdev=mem0 \ -numa node,nodeid=1,cpus=2-3,memdev=mem1 \ -numa node,nodeid=2 \ -numa node,nodeid=3 \ : -device virtio-balloon-pci,id=balloon0,free-page-reporting=yes qemu-system-aarch64: FDT: Failed to create subnode /memory@80000000: \ FDT_ERR_EXISTS This fixes the issue by using NUMA node ID or zero in the memory node name to avoid the conflicting memory node names. With this applied, the VM can boot successfully with above command lines. Signed-off-by: Gavin Shan <gs...@redhat.com> --- hw/arm/boot.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/hw/arm/boot.c b/hw/arm/boot.c index d7b059225e..3169bdf595 100644 --- a/hw/arm/boot.c +++ b/hw/arm/boot.c @@ -432,7 +432,12 @@ static int fdt_add_memory_node(void *fdt, uint32_t acells, hwaddr mem_base, char *nodename; int ret; - nodename = g_strdup_printf("/memory@%" PRIx64, mem_base); + if (numa_node_id >= 0) { + nodename = g_strdup_printf("/memory@%d", numa_node_id); + } else { + nodename = g_strdup("/memory@0"); + } + qemu_fdt_add_subnode(fdt, nodename); qemu_fdt_setprop_string(fdt, nodename, "device_type", "memory"); ret = qemu_fdt_setprop_sized_cells(fdt, nodename, "reg", acells, mem_base, -- 2.23.0