On Mon, Mar 20, 2017 at 03:12:44PM +0100, Laurent Vivier wrote: > Since commit 224245b ("spapr: Add LMB DR connectors"), NUMA node > memory size must be aligned to 256MB (SPAPR_MEMORY_BLOCK_SIZE). > > But when "-numa" option is provided without "mem" parameter, > the memory is equally divided between nodes, but 8MB aligned. > This can be not valid for pseries. > > In that case we can have: > $ ./ppc64-softmmu/qemu-system-ppc64 -m 4G -numa node -numa node -numa node > qemu-system-ppc64: Node 0 memory size 0x55000000 is not aligned to 256 MiB > > With this patch, we have: > (qemu) info numa > 3 nodes > node 0 cpus: 0 > node 0 size: 1280 MB > node 1 cpus: > node 1 size: 1280 MB > node 2 cpus: > node 2 size: 1536 MB > > Signed-off-by: Laurent Vivier <lviv...@redhat.com>
The code looks good, but a few comments explaining the reason for the numa_mem_align_shift values would be interesting. Additional comments below: > --- > v2: > - remove dtc > - Add a field in MachineClass to only modify the > numa node memory alignment value for pseries-2.9 > and upper. > > hw/core/machine.c | 3 +++ > hw/ppc/spapr.c | 2 ++ > include/hw/boards.h | 1 + > numa.c | 4 ++-- > 4 files changed, 8 insertions(+), 2 deletions(-) > > diff --git a/hw/core/machine.c b/hw/core/machine.c > index 0d92672..2ad5ab5 100644 > --- a/hw/core/machine.c > +++ b/hw/core/machine.c > @@ -396,6 +396,9 @@ static void machine_class_init(ObjectClass *oc, void > *data) > mc->default_ram_size = 128 * M_BYTE; > mc->rom_file_has_mr = true; > > + /* numa node memory size aligned on 8MB by default */ > + mc->numa_mem_align_shift = 23; > + This could include the original "On Linux, each node's border has to be 8MB aligned" comment from parse_numa_opts(), to explain the reason for the 8MB default. > object_class_property_add_str(oc, "accel", > machine_get_accel, machine_set_accel, &error_abort); > object_class_property_set_description(oc, "accel", > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > index 6ee566d..1e72fe8 100644 > --- a/hw/ppc/spapr.c > +++ b/hw/ppc/spapr.c > @@ -3096,6 +3096,7 @@ static void spapr_machine_class_init(ObjectClass *oc, > void *data) > xic->ics_resend = spapr_ics_resend; > xic->icp_get = spapr_icp_get; > ispc->print_info = spapr_pic_print_info; > + mc->numa_mem_align_shift = 28; A comment explaining why spapr requires 256MB alignment would be nice. > } > > static const TypeInfo spapr_machine_info = { > @@ -3180,6 +3181,7 @@ static void > spapr_machine_2_8_class_options(MachineClass *mc) > { > spapr_machine_2_9_class_options(mc); > SET_MACHINE_COMPAT(mc, SPAPR_COMPAT_2_8); > + mc->numa_mem_align_shift = 23; > } > > DEFINE_SPAPR_MACHINE(2_8, "2.8", false); > diff --git a/include/hw/boards.h b/include/hw/boards.h > index 269d0ba..31d9c72 100644 > --- a/include/hw/boards.h > +++ b/include/hw/boards.h > @@ -135,6 +135,7 @@ struct MachineClass { > bool rom_file_has_mr; > int minimum_page_bits; > bool has_hotpluggable_cpus; > + int numa_mem_align_shift; > > HotplugHandler *(*get_hotplug_handler)(MachineState *machine, > DeviceState *dev); > diff --git a/numa.c b/numa.c > index e01cb54..98e4d02 100644 > --- a/numa.c > +++ b/numa.c > @@ -338,12 +338,12 @@ void parse_numa_opts(MachineClass *mc) > if (i == nb_numa_nodes) { > uint64_t usedmem = 0; > > - /* On Linux, each node's border has to be 8MB aligned, > + /* On Linux, each node's border has to be aligned, > * the final node gets the rest. > */ I assume that the 256MB alignment in spapr is not just because of Linux (is it?). This makes the comment misleading. I would rewrite it to something like: "Align each node according to the alignment requirements of the machine class". > for (i = 0; i < nb_numa_nodes - 1; i++) { > numa_info[i].node_mem = (ram_size / nb_numa_nodes) & > - ~((1 << 23UL) - 1); > + ~((1 << mc->numa_mem_align_shift) - > 1); > usedmem += numa_info[i].node_mem; > } > numa_info[i].node_mem = ram_size - usedmem; > -- > 2.9.3 > -- Eduardo