Re: [XEN RFC PATCH 22/40] xen/arm: introduce a helper to parse device tree processor node

[Julien Grall]

On 20/08/2021 03:23, Wei Chen wrote:
Hi Julien,

Hi Wei,

-----Original Message-----
From: Julien Grall <jul...@xen.org>
Sent: 2021年8月20日 2:13
To: Wei Chen <wei.c...@arm.com>; xen-devel@lists.xenproject.org;
sstabell...@kernel.org; jbeul...@suse.com
Cc: Bertrand Marquis <bertrand.marq...@arm.com>
Subject: Re: [XEN RFC PATCH 22/40] xen/arm: introduce a helper to parse
device tree processor node

Hi Wei,

On 11/08/2021 11:24, Wei Chen wrote:
Processor NUMA ID information is stored in device tree's processor
node as "numa-node-id". We need a new helper to parse this ID from
processor node. If we get this ID from processor node, this ID's
validity still need to be checked. Once we got a invalid NUMA ID
from any processor node, the device tree will be marked as NUMA
information invalid.

Signed-off-by: Wei Chen <wei.c...@arm.com>
---
   xen/arch/arm/numa_device_tree.c | 41 +++++++++++++++++++++++++++++++--
   1 file changed, 39 insertions(+), 2 deletions(-)

diff --git a/xen/arch/arm/numa_device_tree.c
b/xen/arch/arm/numa_device_tree.c
index 1c74ad135d..37cc56acf3 100644
--- a/xen/arch/arm/numa_device_tree.c
+++ b/xen/arch/arm/numa_device_tree.c
@@ -20,16 +20,53 @@
   #include <xen/init.h>
   #include <xen/nodemask.h>
   #include <xen/numa.h>
+#include <xen/device_tree.h>

Nothing in this file seems to depend on xen/device_tree.h. So why do you
need to include it?


I remember that without this header file, device_tree_get_u32 in this patch
will cause compiling failed.

I looked at the prototype of device_tree_get_u32() and I can't find how 
it depends on bits from device_tree.h. Can you paste the compilation error?


+#include <asm/setup.h>

   s8 device_tree_numa = 0;
+static nodemask_t processor_nodes_parsed __initdata;

-int srat_disabled(void)
+static int srat_disabled(void)
   {
       return numa_off || device_tree_numa < 0;
   }

-void __init bad_srat(void)
+static __init void bad_srat(void)
   {
       printk(KERN_ERR "DT: NUMA information is not used.\n");
       device_tree_numa = -1;
   }
+
+/* Callback for device tree processor affinity */
+static int __init dtb_numa_processor_affinity_init(nodeid_t node)
+{
+    if ( srat_disabled() )
+        return -EINVAL;
+    else if ( node == NUMA_NO_NODE || node >= MAX_NUMNODES ) {
+               bad_srat();
+               return -EINVAL;
+       }
+
+    node_set(node, processor_nodes_parsed);
+
+    device_tree_numa = 1;
+    printk(KERN_INFO "DT: NUMA node %u processor parsed\n", node);
+
+    return 0;
+}
+
+/* Parse CPU NUMA node info */
+int __init device_tree_parse_numa_cpu_node(const void *fdt, int node)
+{
+    uint32_t nid;
+
+    nid = device_tree_get_u32(fdt, node, "numa-node-id", MAX_NUMNODES);
+    printk(XENLOG_WARNING "CPU on NUMA node:%u\n", nid);
+    if ( nid >= MAX_NUMNODES )
+    {
+        printk(XENLOG_WARNING "Node id %u exceeds maximum value\n",
nid);
+        return -EINVAL;
+    }
+
+    return dtb_numa_processor_affinity_init(nid);
+}


--
Julien Grall

Cheers,

--
Julien Grall