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From 6d5bc18c3af1969cfcaea9c9bafb5ad0d32bb163 Mon Sep 17 00:00:00 2001
From: Igor Mammedov <imammedo@redhat.com>
Date: Tue, 7 Aug 2018 12:33:52 +0200
Subject: [PATCH 05/13] pc: acpi: fix memory hotplug regression by reducing
 stub SRAT entry size

RH-Author: Igor Mammedov <imammedo@redhat.com>
Message-id: <1533645232-98572-1-git-send-email-imammedo@redhat.com>
Patchwork-id: 81662
O-Subject: [RHEL-7.6 qemu-kvm-rhev PATCH] pc: acpi: fix memory hotplug regression by reducing stub SRAT entry size
Bugzilla: 1609234
RH-Acked-by: Michael S. Tsirkin <mst@redhat.com>
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
RH-Acked-by: Eduardo Habkost <ehabkost@redhat.com>

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1609234
Brew: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=17640116
Branch: rhv7/master-2.12.0

 1: there is no coldplugged dimm in the last numa node
    but there is a coldplugged dimm in another node

  -m 4096,slots=4,maxmem=32G               \
  -object memory-backend-ram,id=m0,size=2G \
  -device pc-dimm,memdev=m0,node=0         \
  -numa node,nodeid=0                      \
  -numa node,nodeid=1

 2: if order of dimms on CLI is:
       1st plugged dimm in node1
       2nd plugged dimm in node0

  -m 4096,slots=4,maxmem=32G               \
  -object memory-backend-ram,size=2G,id=m0 \
  -device pc-dimm,memdev=m0,node=1         \
  -object memory-backend-ram,id=m1,size=2G \
  -device pc-dimm,memdev=m1,node=0         \
  -numa node,nodeid=0                      \
  -numa node,nodeid=1

(qemu) object_add memory-backend-ram,id=m2,size=1G
(qemu) device_add pc-dimm,memdev=m2,node=0

the first DIMM hotplug to any node except the last one
fails (Windows is unable to online it).

Length reduction of stub hotplug memory SRAT entry,
fixes issue for some reason.

RHBZ: 1609234

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

(cherry picked from commit 10efd7e1088855dc019e6a248ac7f9b24af8dd26)
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 hw/i386/acpi-build.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index b309a97..683e5f4 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -2271,7 +2271,16 @@ static void build_srat_hotpluggable_memory(GArray *table_data, uint64_t base,
         numamem = acpi_data_push(table_data, sizeof *numamem);
 
         if (!info) {
-            build_srat_memory(numamem, cur, end - cur, default_node,
+            /*
+             * Entry is required for Windows to enable memory hotplug in OS
+             * and for Linux to enable SWIOTLB when booted with less than
+             * 4G of RAM. Windows works better if the entry sets proximity
+             * to the highest NUMA node in the machine at the end of the
+             * reserved space.
+             * Memory devices may override proximity set by this entry,
+             * providing _PXM method if necessary.
+             */
+            build_srat_memory(numamem, end - 1, 1, default_node,
                               MEM_AFFINITY_HOTPLUGGABLE | MEM_AFFINITY_ENABLED);
             break;
         }
@@ -2404,14 +2413,6 @@ build_srat(GArray *table_data, BIOSLinker *linker, MachineState *machine)
         build_srat_memory(numamem, 0, 0, 0, MEM_AFFINITY_NOFLAGS);
     }
 
-    /*
-     * Entry is required for Windows to enable memory hotplug in OS
-     * and for Linux to enable SWIOTLB when booted with less than
-     * 4G of RAM. Windows works better if the entry sets proximity
-     * to the highest NUMA node in the machine.
-     * Memory devices may override proximity set by this entry,
-     * providing _PXM method if necessary.
-     */
     if (hotplugabble_address_space_size) {
         build_srat_hotpluggable_memory(table_data, pcms->hotplug_memory.base,
                                        hotplugabble_address_space_size,
-- 
1.8.3.1