Commit 085f8e88 authored by Igor Mammedov's avatar Igor Mammedov Committed by Michael S. Tsirkin
Browse files

pc: count in 1Gb hugepage alignment when sizing hotplug-memory container

if DIMMs with different size/alignment are interleaved
in creation order, it could lead to hotplug-memory
container fragmentation and following inability to use
all RAM upto maxmem.
For example:
    -m 4G,slots=3,maxmem=7G
    -object memory-backend-file,id=mem-1,size=256M,mem-path=/pagesize-2MB
    -device pc-dimm,id=mem1,memdev=mem-1
    -object memory-backend-file,id=mem-2,size=1G,mem-path=/pagesize-1GB
    -device pc-dimm,id=mem2,memdev=mem-2
    -object memory-backend-file,id=mem-3,size=256M,mem-path=/pagesize-2MB
    -device pc-dimm,id=mem3,memdev=mem-3

fragments hotplug-memory container and doesn't allow
to use 1GB hugepage backend to consume remainig 1Gb.

To ease managment factor count in max 1Gb alignment for
each memory slot when sizing hotplug-memory region so
that regadless of fragmentaion it would be possible to
add max aligned DIMM.

Signed-off-by: default avatarIgor Mammedov <>
Reviewed-by: default avatarMichael S. Tsirkin <>
Signed-off-by: default avatarMichael S. Tsirkin <>
parent b03541fa
......@@ -1247,6 +1247,11 @@ FWCfgState *pc_memory_init(MachineState *machine,
pcms->hotplug_memory_base =
ROUND_UP(0x100000000ULL + above_4g_mem_size, 1ULL << 30);
if (pcms->enforce_aligned_dimm) {
/* size hotplug region assuming 1G page max alignment per slot */
hotplug_mem_size += (1ULL << 30) * machine->ram_slots;
if ((pcms->hotplug_memory_base + hotplug_mem_size) <
hotplug_mem_size) {
error_report("unsupported amount of maximum memory: " RAM_ADDR_FMT,
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