From cffbabd734488678614832ff26222aaa10920472 Mon Sep 17 00:00:00 2001

From: Igor Mammedov <imammedo@redhat.com>

Date: Wed, 12 Sep 2018 15:21:41 +0200

Subject: [PATCH 06/49] pc: acpi: revert back to 1 SRAT entry for hotpluggable

 area

RH-Author: Igor Mammedov <imammedo@redhat.com>

Message-id: <1536765701-266415-1-git-send-email-imammedo@redhat.com>

Patchwork-id: 82145

O-Subject: [RHEL-7.6 qemu-kvm-rhev PATCH] pc: acpi: revert back to 1 SRAT entry for hotpluggable area

Bugzilla: 1626059

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>

Commit

  10efd7e108 "pc: acpi: fix memory hotplug regression by reducing stub SRAT entry size"

attemped to fix hotplug regression introduced by

  848a1cc1e "hw/acpi-build: build SRAT memory affinity structures for DIMM devices"

fixed issue for Windows/3.0+ linux kernels, however it regressed 2.6 based

kernels (RHEL6) to the point where guest might crash at boot.

Reason is that 2.6 kernel discards SRAT table due too small last entry

which down the road leads to crashes. Hack I've tried in 10efd7e108 is also

not ACPI spec compliant according to which whole possible RAM should be

described in SRAT. Revert 10efd7e108 to fix regression for 2.6 based kernels.

With 10efd7e108 reverted, I've also tried splitting SRAT table statically

in different ways %/node and %/slot but Windows still fails to online

2nd pc-dimm hot-plugged into node 0 (as described in 10efd7e108) and

sometimes even coldplugged pc-dimms where affected with static SRAT

partitioning.

The only known so far way where Windows stays happy is when we have 1

SRAT entry in the last node covering all hotplug area.

Revert 848a1cc1e until we come up with a way to avoid regression

on Windows with hotplug area split in several entries.

Tested this with 2.6/3.0 based kernels (RHEL6/7) and WS20[08/12/12R2/16]).

Signed-off-by: Igor Mammedov <imammedo@redhat.com>

Acked-by: Laszlo Ersek <lersek@redhat.com>

Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

(pull request  https://www.mail-archive.com/qemu-devel@nongnu.org/msg560638.html)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

Conflicts:

  hw/i386/acpi-build.c

    - contextual conflict since we do not have

         (d471bf3e hw/i386: Use the IEC binary prefix definitions)

         (b0c14ec4 machine: make MemoryHotplugState accessible via the machine)

Since it's blocker and urgent, sending patch without waiting for upstream

commit id (pull req is out there but it looks like Peter is absent to merge it)

---

 hw/i386/acpi-build.c | 74 +++++++++-------------------------------------------

 1 file changed, 13 insertions(+), 61 deletions(-)

diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c

index 683e5f4..2bc8117 100644

--- a/hw/i386/acpi-build.c

+++ b/hw/i386/acpi-build.c

@@ -2253,64 +2253,6 @@ build_tpm2(GArray *table_data, BIOSLinker *linker, GArray *tcpalog)

 #define HOLE_640K_START  (640 * 1024)

 #define HOLE_640K_END   (1024 * 1024)

-static void build_srat_hotpluggable_memory(GArray *table_data, uint64_t base,

-                                           uint64_t len, int default_node)

-{

-    MemoryDeviceInfoList *info_list = qmp_pc_dimm_device_list();

-    MemoryDeviceInfoList *info;

-    MemoryDeviceInfo *mi;

-    PCDIMMDeviceInfo *di;

-    uint64_t end = base + len, cur, size;

-    bool is_nvdimm;

-    AcpiSratMemoryAffinity *numamem;

-    MemoryAffinityFlags flags;

-

-    for (cur = base, info = info_list;

-         cur < end;

-         cur += size, info = info->next) {

-        numamem = acpi_data_push(table_data, sizeof *numamem);

-

-        if (!info) {

-            /*

-             * 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;

-        }

-

-        mi = info->value;

-        is_nvdimm = (mi->type == MEMORY_DEVICE_INFO_KIND_NVDIMM);

-        di = !is_nvdimm ? mi->u.dimm.data : mi->u.nvdimm.data;

-

-        if (cur < di->addr) {

-            build_srat_memory(numamem, cur, di->addr - cur, default_node,

-                              MEM_AFFINITY_HOTPLUGGABLE | MEM_AFFINITY_ENABLED);

-            numamem = acpi_data_push(table_data, sizeof *numamem);

-        }

-

-        size = di->size;

-

-        flags = MEM_AFFINITY_ENABLED;

-        if (di->hotpluggable) {

-            flags |= MEM_AFFINITY_HOTPLUGGABLE;

-        }

-        if (is_nvdimm) {

-            flags |= MEM_AFFINITY_NON_VOLATILE;

-        }

-

-        build_srat_memory(numamem, di->addr, size, di->node, flags);

-    }

-

-    qapi_free_MemoryDeviceInfoList(info_list);

-}

-

 static void

 build_srat(GArray *table_data, BIOSLinker *linker, MachineState *machine)

 {

@@ -2413,10 +2355,20 @@ 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 at the end of the

+     * reserved space.

+     * 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,

-                                       pcms->numa_nodes - 1);

+        numamem = acpi_data_push(table_data, sizeof *numamem);

+        build_srat_memory(numamem, pcms->hotplug_memory.base,

+                          hotplugabble_address_space_size, pcms->numa_nodes - 1,

+                          MEM_AFFINITY_HOTPLUGGABLE | MEM_AFFINITY_ENABLED);

     }

     build_header(linker, table_data,

-- 

1.8.3.1