[PATCH v6 15/17] xen/arm: Set correct per-cpu cpu_core_mask

[Henry Wang <Henry.Wang@xxxxxxx>]

In the common sysctl command XEN_SYSCTL_physinfo, the cores_per_socket
is calculated based on the cpu_core_mask of CPU0. Currently on Arm
this is a fixed value 1 (can be checked via xl info), which is not
correct. This is because during the Arm cpu online process,
set_cpu_sibling_map() only sets the per-cpu cpu_core_mask for itself.

cores_per_socket refers to the number of cores that belong to the same
socket (NUMA node). Therefore, this commit introduces a helper function
numa_set_cpu_core_mask(cpu), which sets the per-cpu cpu_core_mask to
the cpus in the same NUMA node as cpu. Calling this function at the
boot time can ensure the correct cpu_core_mask, leading to the correct
cores_per_socket to be returned by XEN_SYSCTL_physinfo.

Signed-off-by: Henry Wang <Henry.Wang@xxxxxxx>
---
v6:
- Rebase on top of staging without code changes.
---
 xen/arch/arm/include/asm/numa.h |  7 +++++++
 xen/arch/arm/numa.c             | 11 +++++++++++
 xen/arch/arm/setup.c            |  5 +++++
 3 files changed, 23 insertions(+)

diff --git a/xen/arch/arm/include/asm/numa.h b/xen/arch/arm/include/asm/numa.h
index 71b95a9a62..d4c89909d0 100644
--- a/xen/arch/arm/include/asm/numa.h
+++ b/xen/arch/arm/include/asm/numa.h
@@ -46,6 +46,7 @@ extern void numa_set_distance(nodeid_t from, nodeid_t to,
 extern void numa_detect_cpu_node(unsigned int cpu);
 extern int numa_device_tree_init(const void *fdt);
 extern void numa_init(void);
+extern void numa_set_cpu_core_mask(int cpu);
 
 /*
  * Device tree NUMA doesn't have architecural node id.
@@ -62,6 +63,12 @@ static inline unsigned int numa_node_to_arch_nid(nodeid_t n)
 #define cpu_to_node(cpu) 0
 #define node_to_cpumask(node)   (cpu_online_map)
 
+static inline void numa_set_cpu_core_mask(int cpu)
+{
+    cpumask_or(per_cpu(cpu_core_mask, cpu),
+               per_cpu(cpu_core_mask, cpu), &cpu_possible_map);
+}
+
 /*
  * TODO: make first_valid_mfn static when NUMA is supported on Arm, this
  * is required because the dummy helpers are using it.
diff --git a/xen/arch/arm/numa.c b/xen/arch/arm/numa.c
index 13a167fc4f..1ac2df37fc 100644
--- a/xen/arch/arm/numa.c
+++ b/xen/arch/arm/numa.c
@@ -52,6 +52,17 @@ int __init arch_numa_setup(const char *opt)
     return -EINVAL;
 }
 
+void numa_set_cpu_core_mask(int cpu)
+{
+    nodeid_t node = cpu_to_node[cpu];
+
+    if ( node == NUMA_NO_NODE )
+        node = 0;
+
+    cpumask_or(per_cpu(cpu_core_mask, cpu),
+               per_cpu(cpu_core_mask, cpu), &node_to_cpumask(node));
+}
+
 void __init numa_set_distance(nodeid_t from, nodeid_t to,
                               unsigned int distance)
 {
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 01affc12d9..af8631b6e5 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -1229,6 +1229,11 @@ void __init start_xen(unsigned long boot_phys_offset,
     }
 
     printk("Brought up %ld CPUs\n", (long)num_online_cpus());
+
+    /* Set per-cpu cpu_core_mask to cpus that belongs to the same NUMA node. */
+    for_each_online_cpu ( i )
+        numa_set_cpu_core_mask(i);
+
     /* TODO: smp_cpus_done(); */
 
     /* This should be done in a vpmu driver but we do not have one yet. */
-- 
2.25.1