[PATCH v2 1/2] hmat acpi: Do not add Memory Proximity Domain Attributes Structure targetting non existent memory.

[Jonathan Cameron]

If qemu is started with a proximity node containing CPUs alone,
it will provide one of these structures to say memory in this
node is directly connected to itself.

This description is arguably pointless even if there is memory
in the node.  If there is no memory present, and hence no SRAT
entry it breaks Linux HMAT passing and the table is rejected.

https://elixir.bootlin.com/linux/v6.7/source/drivers/acpi/numa/hmat.c#L444

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

----
v2: Fix link in patch description to be stable.
---
 hw/acpi/hmat.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/hw/acpi/hmat.c b/hw/acpi/hmat.c
index 3042d223c8..723ae28d32 100644
--- a/hw/acpi/hmat.c
+++ b/hw/acpi/hmat.c
@@ -204,6 +204,13 @@ static void hmat_build_table_structs(GArray *table_data, 
NumaState *numa_state)
     build_append_int_noprefix(table_data, 0, 4); /* Reserved */
 
     for (i = 0; i < numa_state->num_nodes; i++) {
+        /*
+         * Linux rejects whole HMAT table if a node with no memory
+         * has one of these structures listing it as a target.
+         */
+        if (!numa_state->nodes[i].node_mem) {
+            continue;
+        }
         flags = 0;
 
         if (numa_state->nodes[i].initiator < MAX_NODES) {
-- 
2.39.2