Re: [Qemu-devel] [PATCH] pc: ACPI BIOS: use highest NUMA node for hotplug mem hole SRAT entry

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, May 24, 2017 at 11:16:14AM +0200, Ladi Prosek wrote:
> On Wed, May 24, 2017 at 11:07 AM, Laszlo Ersek <lersek@redhat.com> wrote:
> > On 05/24/17 10:09, Ladi Prosek wrote:
> >> For reasons unknown, Windows won't online all memory, both at command
> >> line and hot-plugged later, unless the hotplug mem hole SRAT entry
> >> specifies a node greater or equal to the ones where memory is added.
> >
> > s/greater or equal to/greater *than* or equal to/
> >
> > Thanks,
> > Laszlo
> > (always finding the important issues! ;) )
> 
> Haha, thanks! Igor, please let me know if you'd like me to send a
> corrected version.

Yes and pls include Igor's note to maintainer after --- so I don't
forget.

> >>
> >> Using the highest node on the machine makes recent versions of Windows
> >> happy.
> >>
> >> With this example command line:
> >>   ... \
> >>   -m 1024,slots=4,maxmem=32G \
> >>   -numa node,nodeid=0 \
> >>   -numa node,nodeid=1 \
> >>   -numa node,nodeid=2 \
> >>   -numa node,nodeid=3 \
> >>   -object memory-backend-ram,size=1G,id=mem-mem1 \
> >>   -device pc-dimm,id=dimm-mem1,memdev=mem-mem1,node=1
> >>
> >> Windows reports a total of 1G of RAM without this commit and the expected
> >> 2G with this commit.
> >>
> >> Signed-off-by: Ladi Prosek <lprosek@redhat.com>
> >> ---
> >>  hw/i386/acpi-build.c | 7 +++++--
> >>  1 file changed, 5 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> >> index afcadac..9653583 100644
> >> --- a/hw/i386/acpi-build.c
> >> +++ b/hw/i386/acpi-build.c
> >> @@ -2404,14 +2404,17 @@ build_srat(GArray *table_data, BIOSLinker *linker, MachineState *machine)
> >>      }
> >>
> >>      /*
> >> -     * Entry is required for Windows to enable memory hotplug in OS.
> >> +     * Entry is required for Windows to enable memory hotplug in OS
> >> +     * and for Linux to enable SWIOTLB even if booted with less than
> >> +     * 4G of RAM. Windows works better if the entry sets proximity
> >> +     * to the highest NUMA node in the machine.
> >>       * Memory devices may override proximity set by this entry,
> >>       * providing _PXM method if necessary.
> >>       */
> >>      if (hotplugabble_address_space_size) {
> >>          numamem = acpi_data_push(table_data, sizeof *numamem);
> >>          build_srat_memory(numamem, pcms->hotplug_memory.base,
> >> -                          hotplugabble_address_space_size, 0,
> >> +                          hotplugabble_address_space_size, pcms->numa_nodes - 1,
> >>                            MEM_AFFINITY_HOTPLUGGABLE | MEM_AFFINITY_ENABLED);
> >>      }
> >>
> >>
> >