[PATCH v2 2/2] spapr: Add a new level of NUMA for GPUs

[Reza Arbab]

NUMA nodes corresponding to GPU memory currently have the same
affinity/distance as normal memory nodes. Add a third NUMA associativity
reference point enabling us to give GPU nodes more distance.

This is guest visible information, which shouldn't change under a
running guest across migration between different qemu versions, so make
the change effective only in new (pseries > 5.0) machine types.

Before, `numactl -H` output in a guest with 4 GPUs (nodes 2-5):

node distances:
node   0   1   2   3   4   5
  0:  10  40  40  40  40  40
  1:  40  10  40  40  40  40
  2:  40  40  10  40  40  40
  3:  40  40  40  10  40  40
  4:  40  40  40  40  10  40
  5:  40  40  40  40  40  10

After:

node distances:
node   0   1   2   3   4   5
  0:  10  40  80  80  80  80
  1:  40  10  80  80  80  80
  2:  80  80  10  80  80  80
  3:  80  80  80  10  80  80
  4:  80  80  80  80  10  80
  5:  80  80  80  80  80  10

These are the same distances as on the host, mirroring the change made
to host firmware in skiboot commit f845a648b8cb ("numa/associativity:
Add a new level of NUMA for GPU's").

Signed-off-by: Reza Arbab <ar...@linux.ibm.com>
---
 hw/ppc/spapr.c             | 11 +++++++++--
 hw/ppc/spapr_pci_nvlink2.c |  2 +-
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 88b4a1f17716..1d9193d5ee49 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -893,7 +893,11 @@ static void spapr_dt_rtas(SpaprMachineState *spapr, void 
*fdt)
     int rtas;
     GString *hypertas = g_string_sized_new(256);
     GString *qemu_hypertas = g_string_sized_new(256);
-    uint32_t refpoints[] = { cpu_to_be32(0x4), cpu_to_be32(0x4) };
+    uint32_t refpoints[] = {
+        cpu_to_be32(0x4),
+        cpu_to_be32(0x4),
+        cpu_to_be32(0x2),
+    };
     uint32_t nr_refpoints;
     uint64_t max_device_addr = MACHINE(spapr)->device_memory->base +
         memory_region_size(&MACHINE(spapr)->device_memory->mr);
@@ -4544,7 +4548,7 @@ static void spapr_machine_class_init(ObjectClass *oc, 
void *data)
     smc->linux_pci_probe = true;
     smc->smp_threads_vsmt = true;
     smc->nr_xirqs = SPAPR_NR_XIRQS;
-    smc->nr_assoc_refpoints = 2;
+    smc->nr_assoc_refpoints = 3;
     xfc->match_nvt = spapr_match_nvt;
 }
 
@@ -4611,8 +4615,11 @@ DEFINE_SPAPR_MACHINE(5_1, "5.1", true);
  */
 static void spapr_machine_5_0_class_options(MachineClass *mc)
 {
+    SpaprMachineClass *smc = SPAPR_MACHINE_CLASS(mc);
+
     spapr_machine_5_1_class_options(mc);
     compat_props_add(mc->compat_props, hw_compat_5_0, hw_compat_5_0_len);
+    smc->nr_assoc_refpoints = 2;
 }
 
 DEFINE_SPAPR_MACHINE(5_0, "5.0", false);
diff --git a/hw/ppc/spapr_pci_nvlink2.c b/hw/ppc/spapr_pci_nvlink2.c
index 8332d5694e46..247fd48731e2 100644
--- a/hw/ppc/spapr_pci_nvlink2.c
+++ b/hw/ppc/spapr_pci_nvlink2.c
@@ -362,7 +362,7 @@ void spapr_phb_nvgpu_ram_populate_dt(SpaprPhbState *sphb, 
void *fdt)
         uint32_t associativity[] = {
             cpu_to_be32(0x4),
             SPAPR_GPU_NUMA_ID,
-            SPAPR_GPU_NUMA_ID,
+            cpu_to_be32(nvslot->numa_id),
             SPAPR_GPU_NUMA_ID,
             cpu_to_be32(nvslot->numa_id)
         };
-- 
2.18.2