Re: [PATCH v4 2/3] spapr_numa: create a vcpu associativity helper

[Daniel Henrique Barboza]

On 9/4/20 1:10 AM, David Gibson wrote:

On Thu, Sep 03, 2020 at 10:04:38PM -0300, Daniel Henrique Barboza wrote:

The work to be done in h_home_node_associativity() intersects
with what is already done in spapr_numa_fixup_cpu_dt(). This
patch creates a new helper, spapr_numa_get_vcpu_assoc(), to
be used for both spapr_numa_fixup_cpu_dt() and
h_home_node_associativity().

While we're at it, use memcpy() instead of loop assignment
to created the returned array.

Signed-off-by: Daniel Henrique Barboza <danielhb...@gmail.com>
---
  hw/ppc/spapr_numa.c | 30 ++++++++++++++++++++----------
  1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/hw/ppc/spapr_numa.c b/hw/ppc/spapr_numa.c
index 368c1a494d..980a6488bf 100644
--- a/hw/ppc/spapr_numa.c
+++ b/hw/ppc/spapr_numa.c
@@ -71,13 +71,15 @@ void spapr_numa_write_associativity_dt(SpaprMachineState 
*spapr, void *fdt,
                        sizeof(spapr->numa_assoc_array[nodeid]))));
  }

-int spapr_numa_fixup_cpu_dt(SpaprMachineState *spapr, void *fdt,

-                            int offset, PowerPCCPU *cpu)
+static uint32_t *spapr_numa_get_vcpu_assoc(SpaprMachineState *spapr,
+                                          PowerPCCPU *cpu,
+                                          uint *vcpu_assoc_size)
  {
-    uint vcpu_assoc_size = NUMA_ASSOC_SIZE + 1;
-    uint32_t vcpu_assoc[vcpu_assoc_size];
+    uint32_t *vcpu_assoc = NULL;
      int index = spapr_get_vcpu_id(cpu);
-    int i;
+
+    *vcpu_assoc_size = (NUMA_ASSOC_SIZE + 1) * sizeof(uint32_t);
+    vcpu_assoc = g_malloc(*vcpu_assoc_size);

/*

       * VCPUs have an extra 'cpu_id' value in ibm,associativity
@@ -86,16 +88,24 @@ int spapr_numa_fixup_cpu_dt(SpaprMachineState *spapr, void 
*fdt,
       * cpu_id last.
       */
      vcpu_assoc[0] = cpu_to_be32(MAX_DISTANCE_REF_POINTS + 1);
+    memcpy(vcpu_assoc + 1, spapr->numa_assoc_array[cpu->node_id],
+           MAX_DISTANCE_REF_POINTS);

That needs to be MAX_DISTANCE_REF_POINTS * sizeof(uint32_t), doesn't it?

Hmmmm yeah it does. Even if this didn't break spectacularly in my guest (not
sure why), we're doing a similar operation in 
spapr_numa_write_assoc_lookup_arrays()
using 'sizeof(uint32_t)'. Might as well do the same here.


Thanks,



DHB

+    vcpu_assoc[MAX_DISTANCE_REF_POINTS + 1] = cpu_to_be32(index);

- for (i = 1; i <= MAX_DISTANCE_REF_POINTS; i++) {

-        vcpu_assoc[i] = spapr->numa_assoc_array[cpu->node_id][i];
-    }
+    return vcpu_assoc;
+}
+
+int spapr_numa_fixup_cpu_dt(SpaprMachineState *spapr, void *fdt,
+                            int offset, PowerPCCPU *cpu)
+{
+    g_autofree uint32_t *vcpu_assoc = NULL;
+    uint vcpu_assoc_size;

- vcpu_assoc[vcpu_assoc_size - 1] = cpu_to_be32(index);

+    vcpu_assoc = spapr_numa_get_vcpu_assoc(spapr, cpu, &vcpu_assoc_size);

/* Advertise NUMA via ibm,associativity */

      return fdt_setprop(fdt, offset, "ibm,associativity",
-                       vcpu_assoc, sizeof(vcpu_assoc));
+                       vcpu_assoc, vcpu_assoc_size);>  }