Currently, Using the fisrt node without memory on the machine makes
QEMU unhappy. With this example command line:
  ... \
  -m 1024M,slots=4,maxmem=32G \
  -numa node,nodeid=0 \
  -numa node,mem=1024M,nodeid=1 \
  -numa node,nodeid=2 \
  -numa node,nodeid=3 \
Guest reports "No NUMA configuration found" and the NUMA topology is
wrong.

This is because when QEMU builds ACPI SRAT, it regards node0 as the
default node to deal with the memory hole(640K-1M). this means the
node0 must have some memory(>1M), but, actually it can have no
memory.

Fix this problem by replace the node0 with the first node which has
memory on it. Add a new function for each node. Also do some cleanup.

Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
---
 hw/i386/acpi-build.c | 76 +++++++++++++++++++++++++++++++++-------------------
 1 file changed, 48 insertions(+), 28 deletions(-)

diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 98dd424..e5f57d2 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -2318,15 +2318,43 @@ build_tpm2(GArray *table_data, BIOSLinker *linker)
                  (void *)tpm2_ptr, "TPM2", sizeof(*tpm2_ptr), 4, NULL, NULL);
 }
 
+static uint64_t
+build_srat_node_entry(GArray *table_data, PCMachineState *pcms,
+                                int i, uint64_t mem_base, uint64_t mem_len)
+{
+    AcpiSratMemoryAffinity *numamem;
+    uint64_t next_base;
+
+    next_base = mem_base + mem_len;
+
+    /* Cut out the ACPI_PCI hole */
+    if (mem_base <= pcms->below_4g_mem_size &&
+        next_base > pcms->below_4g_mem_size) {
+        mem_len -= next_base - pcms->below_4g_mem_size;
+        if (mem_len > 0) {
+            numamem = acpi_data_push(table_data, sizeof *numamem);
+            build_srat_memory(numamem, mem_base, mem_len, i,
+                              MEM_AFFINITY_ENABLED);
+        }
+        mem_base = 1ULL << 32;
+        mem_len = next_base - pcms->below_4g_mem_size;
+        next_base += (1ULL << 32) - pcms->below_4g_mem_size;
+    }
+    numamem = acpi_data_push(table_data, sizeof *numamem);
+    build_srat_memory(numamem, mem_base, mem_len, i,
+                      MEM_AFFINITY_ENABLED);
+    return next_base;
+}
+
 static void
 build_srat(GArray *table_data, BIOSLinker *linker, MachineState *machine)
 {
     AcpiSystemResourceAffinityTable *srat;
     AcpiSratMemoryAffinity *numamem;
 
-    int i;
+    int i, node;
     int srat_start, numa_start, slots;
-    uint64_t mem_len, mem_base, next_base;
+    uint64_t mem_len, mem_base;
     MachineClass *mc = MACHINE_GET_CLASS(machine);
     const CPUArchIdList *apic_ids = mc->possible_cpu_arch_ids(machine);
     PCMachineState *pcms = PC_MACHINE(machine);
@@ -2370,36 +2398,28 @@ build_srat(GArray *table_data, BIOSLinker *linker, MachineState *machine)
     /* the memory map is a bit tricky, it contains at least one hole
      * from 640k-1M and possibly another one from 3.5G-4G.
      */
-    next_base = 0;
+
     numa_start = table_data->len;
 
+    /* get the first node which has memory and  map the hole from 640K-1M */
+    for (node = 0;
+            node < pcms->numa_nodes && pcms->node_mem[node] == 0;
+            node++);
     numamem = acpi_data_push(table_data, sizeof *numamem);
-    build_srat_memory(numamem, 0, 640 * 1024, 0, MEM_AFFINITY_ENABLED);
-    next_base = 1024 * 1024;
-    for (i = 1; i < pcms->numa_nodes + 1; ++i) {
-        mem_base = next_base;
-        mem_len = pcms->node_mem[i - 1];
-        if (i == 1) {
-            mem_len -= 1024 * 1024;
-        }
-        next_base = mem_base + mem_len;
-
-        /* Cut out the ACPI_PCI hole */
-        if (mem_base <= pcms->below_4g_mem_size &&
-            next_base > pcms->below_4g_mem_size) {
-            mem_len -= next_base - pcms->below_4g_mem_size;
-            if (mem_len > 0) {
-                numamem = acpi_data_push(table_data, sizeof *numamem);
-                build_srat_memory(numamem, mem_base, mem_len, i - 1,
-                                  MEM_AFFINITY_ENABLED);
-            }
-            mem_base = 1ULL << 32;
-            mem_len = next_base - pcms->below_4g_mem_size;
-            next_base += (1ULL << 32) - pcms->below_4g_mem_size;
+    build_srat_memory(numamem, 0, 640 * 1024, node, MEM_AFFINITY_ENABLED);
+
+    /* map the rest of memory from 1M */
+    mem_base = 1024 * 1024;
+    mem_len = pcms->node_mem[node] - mem_base;
+    mem_base = build_srat_node_entry(table_data, pcms, node,
+                                            mem_base, mem_len);
+
+    for (i = 0; i < pcms->numa_nodes; i++) {
+        if (i == node) {
+            continue;
         }
-        numamem = acpi_data_push(table_data, sizeof *numamem);
-        build_srat_memory(numamem, mem_base, mem_len, i - 1,
-                          MEM_AFFINITY_ENABLED);
+        mem_base = build_srat_node_entry(table_data, pcms, i,
+                                            mem_base, pcms->node_mem[i]);
     }
     slots = (table_data->len - numa_start) / sizeof *numamem;
     for (; slots < pcms->numa_nodes + 2; slots++) {
-- 
2.5.5

Hi,

This series seems to have some coding style problems. See output below for
more information:

Message-id: 1502787511-20894-1-git-send-email-douly.fnst@cn.fujitsu.com
Subject: [Qemu-devel] [PATCH] hw/acpi: Select an node with memory for mapping memory hole to
Type: series

=== TEST SCRIPT BEGIN ===
#!/bin/bash

BASE=base
n=1
total=$(git log --oneline $BASE.. | wc -l)
failed=0

git config --local diff.renamelimit 0
git config --local diff.renames True

commits="$(git log --format=%H --reverse $BASE..)"
for c in $commits; do
    echo "Checking PATCH $n/$total: $(git log -n 1 --format=%s $c)..."
    if ! git show $c --format=email | ./scripts/checkpatch.pl --mailback -; then
        failed=1
        echo
    fi
    n=$((n+1))
done

exit $failed
=== TEST SCRIPT END ===

Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384
From https://github.com/patchew-project/qemu
 * [new tag]               patchew/20170815085732.9794-1-ldoktor@redhat.com -> patchew/20170815085732.9794-1-ldoktor@redhat.com
Switched to a new branch 'test'
8d4d56ba54 hw/acpi: Select an node with memory for mapping memory hole to

=== OUTPUT BEGIN ===
Checking PATCH 1/1: hw/acpi: Select an node with memory for mapping memory hole to...
ERROR: trailing statements should be on next line
#88: FILE: hw/i386/acpi-build.c:2405:
+    for (node = 0;
[...]
+            node++);

total: 1 errors, 0 warnings, 99 lines checked

Your patch has style problems, please review.  If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.

=== OUTPUT END ===

Test command exited with code: 1


---
Email generated automatically by Patchew [http://patchew.org/].
Please send your feedback to patchew-devel@freelists.org