Re: [Qemu-devel] [PATCH-for-4.2 v8 7/9] hw/arm/virt-acpi-build: Add PC-DIMM in SRAT

[Shameerali Kolothum Thodi]

Hi Igor,

> -----Original Message-----
> From: Qemu-devel
> [mailto:qemu-devel-bounces+shameerali.kolothum.thodi=huawei.com@nongn
> u.org] On Behalf Of Igor Mammedov
> Sent: 06 August 2019 14:22
> To: Shameerali Kolothum Thodi <address@hidden>
> Cc: address@hidden; address@hidden;
> address@hidden; address@hidden;
> address@hidden; xuwei (O) <address@hidden>; Linuxarm
> <address@hidden>; address@hidden; address@hidden;
> address@hidden; address@hidden
> Subject: Re: [Qemu-devel] [PATCH-for-4.2 v8 7/9] hw/arm/virt-acpi-build: Add
> PC-DIMM in SRAT
> 
> On Fri, 26 Jul 2019 11:45:17 +0100
> Shameer Kolothum <address@hidden> wrote:
> 
> > Generate Memory Affinity Structures for PC-DIMM ranges.
> >
> > Signed-off-by: Shameer Kolothum <address@hidden>
> > Signed-off-by: Eric Auger <address@hidden>
> > Reviewed-by: Igor Mammedov <address@hidden>
> > ---
> >  hw/arm/virt-acpi-build.c | 9 +++++++++
> >  1 file changed, 9 insertions(+)
> >
> > diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
> > index 018b1e326d..75657caa36 100644
> > --- a/hw/arm/virt-acpi-build.c
> > +++ b/hw/arm/virt-acpi-build.c
> > @@ -518,6 +518,7 @@ build_srat(GArray *table_data, BIOSLinker *linker,
> VirtMachineState *vms)
> >      int i, srat_start;
> >      uint64_t mem_base;
> >      MachineClass *mc = MACHINE_GET_CLASS(vms);
> > +    MachineState *ms = MACHINE(vms);
> >      const CPUArchIdList *cpu_list =
> mc->possible_cpu_arch_ids(MACHINE(vms));
> >
> >      srat_start = table_data->len;
> > @@ -543,6 +544,14 @@ build_srat(GArray *table_data, BIOSLinker *linker,
> VirtMachineState *vms)
> >          }
> >      }
> >
> > +    if (ms->device_memory) {
> > +        numamem = acpi_data_push(table_data, sizeof *numamem);
> > +        build_srat_memory(numamem, ms->device_memory->base,
> > +
> memory_region_size(&ms->device_memory->mr),
> > +                          nb_numa_nodes - 1,
> > +                          MEM_AFFINITY_HOTPLUGGABLE |
> MEM_AFFINITY_ENABLED);
> > +    }
> > +
> >      build_header(linker, table_data, (void *)(table_data->data +
> srat_start),
> >                   "SRAT", table_data->len - srat_start, 3, NULL, NULL);
> >  }
> 
> missing entry in
>   tests/bios-tables-test-allowed-diff.h

I can't find any SRAT file in tests/data/acpi/virt. Arm/virt doesn't have much
tests in bios-tables-test.c. So does it make any difference?

> PS:
> I don't really know what ARM guest kernel expects but on x86 we had to enable
> numa
> for guest to figure out max_possible_pfn
> (see: in linux.git: 8dd330300197 / ec941c5ffede).

>From whatever I can find, doesn't look like there is any special handling of
max_possible_pfn in ARM64 world. The variable seems to be only updated
in acpi_numa_memory_affinity_init()

https://elixir.bootlin.com/linux/v5.3-rc3/source/drivers/acpi/numa.c#L298

Is there any way to test this in Guest to see whether this is actually a 
problem?

Thanks,
Shameer

> It's worth to check if we might need a patch for turning on NUMA
> (how to do it in QEMU see: auto_enable_numa_with_memhp)