[Qemu-devel] [PATCH v3] NUMA: Enable adding NUMA node implicitly

[Qemu-devel] [PATCH v3] NUMA: Enable adding NUMA node implicitly

[Dou Liyang]

Linux and Windows need ACPI SRAT table to make memory hotplug work properly,
however currently QEMU doesn't create SRAT table if numa options aren't present
on CLI.

Which breaks both linux and windows guests in certain conditions:
 * Windows: won't enable memory hotplug without SRAT table at all
 * Linux: if QEMU is started with initial memory all below 4Gb and no SRAT table
   present, guest kernel will use nommu DMA ops, which breaks 32bit hw drivers
   when memory is hotplugged and guest tries to use it with that drivers.

Fix above issues by automatically creating a numa node when QEMU is started with
memory hotplug enabled but without '-numa' options on CLI.
(PS: auto-create numa node only for new machine types so not to break migration).

Which would provide SRAT table to guests without explicit -numa options on CLI
and would allow:
 * Windows: to enable memory hotplug
 * Linux: switch to SWIOTLB DMA ops, to bounce DMA transfers to 32bit allocated
   buffers that legacy drivers/hw can handle.

[Rewritten by Igor]

Reported-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Suggested-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Marcel Apfelbaum <marcel@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Thomas Huth <thuth@redhat.com>
Cc: Alistair Francis <alistair23@gmail.com>
Cc: f4bug@amsat.org
Cc: Takao Indoh <indou.takao@jp.fujitsu.com>
Cc: Izumi Taku <izumi.taku@jp.fujitsu.com>
---
changelog V2 --> V3:
  -Replace the callback function with a boolean parameter suggested by Igor
  -Use QTAILQ_EMPTY() macro to check the QemuOptsList

 hw/i386/pc.c          |  1 +
 hw/i386/pc_piix.c     |  1 +
 hw/i386/pc_q35.c      |  1 +
 include/hw/boards.h   |  1 +
 include/sysemu/numa.h |  2 +-
 numa.c                | 24 ++++++++++++++++++++++--
 vl.c                  |  9 +++++----
 7 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 05985d4..f1a44cc 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -2318,6 +2318,7 @@ static void pc_machine_class_init(ObjectClass *oc, void *data)
     mc->cpu_index_to_instance_props = pc_cpu_index_to_props;
     mc->get_default_cpu_node_id = pc_get_default_cpu_node_id;
     mc->possible_cpu_arch_ids = pc_possible_cpu_arch_ids;
+    mc->auto_enable_numa_with_memhp = true;
     mc->has_hotpluggable_cpus = true;
     mc->default_boot_order = "cad";
     mc->hot_add_cpu = pc_hot_add_cpu;
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 9ff79b1..d87a433 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -449,6 +449,7 @@ static void pc_i440fx_2_10_machine_options(MachineClass *m)
     m->is_default = 0;
     m->alias = NULL;
     SET_MACHINE_COMPAT(m, PC_COMPAT_2_10);
+    m->auto_enable_numa_with_memhp = false;
 }
 
 DEFINE_I440FX_MACHINE(v2_10, "pc-i440fx-2.10", NULL,
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 6c4ec4b..68cbfc5 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -319,6 +319,7 @@ static void pc_q35_2_10_machine_options(MachineClass *m)
     m->alias = NULL;
     SET_MACHINE_COMPAT(m, PC_COMPAT_2_10);
     m->numa_auto_assign_ram = numa_legacy_auto_assign_ram;
+    m->auto_enable_numa_with_memhp = false;
 }
 
 DEFINE_Q35_MACHINE(v2_10, "pc-q35-2.10", NULL,
diff --git a/include/hw/boards.h b/include/hw/boards.h
index 156e0a5..0fe2c8f 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -191,6 +191,7 @@ struct MachineClass {
     bool has_hotpluggable_cpus;
     bool ignore_memory_transaction_failures;
     int numa_mem_align_shift;
+    bool auto_enable_numa_with_memhp;
     void (*numa_auto_assign_ram)(MachineClass *mc, NodeInfo *nodes,
                                  int nb_nodes, ram_addr_t size);
 
diff --git a/include/sysemu/numa.h b/include/sysemu/numa.h
index 5c6df28..31d3ac0 100644
--- a/include/sysemu/numa.h
+++ b/include/sysemu/numa.h
@@ -30,7 +30,7 @@ struct NumaNodeMem {
 };
 
 extern NodeInfo numa_info[MAX_NODES];
-void parse_numa_opts(MachineState *ms);
+void parse_numa_opts(MachineState *ms, uint64_t ram_slots);
 void query_numa_node_mem(NumaNodeMem node_mem[]);
 extern QemuOptsList qemu_numa_opts;
 void numa_set_mem_node_id(ram_addr_t addr, uint64_t size, uint32_t node);
diff --git a/numa.c b/numa.c
index 100a67f..ba8d813 100644
--- a/numa.c
+++ b/numa.c
@@ -423,12 +423,32 @@ void numa_default_auto_assign_ram(MachineClass *mc, NodeInfo *nodes,
     nodes[i].node_mem = size - usedmem;
 }
 
-void parse_numa_opts(MachineState *ms)
+void parse_numa_opts(MachineState *ms, uint64_t ram_slots)
 {
     int i;
     MachineClass *mc = MACHINE_GET_CLASS(ms);
+    QemuOptsList *numa_opts = qemu_find_opts("numa");
 
-    if (qemu_opts_foreach(qemu_find_opts("numa"), parse_numa, ms, NULL)) {
+    /*
+     * If memory hotplug is enabled (slots > 0) but without '-numa'
+     * options explicitly on CLI, guestes will break.
+     *
+     *   Windows: won't enable memory hotplug without SRAT table at all
+     *
+     *   Linux: if QEMU is started with initial memory all below 4Gb
+     *   and no SRAT table present, guest kernel will use nommu DMA ops,
+     *   which breaks 32bit hw drivers when memory is hotplugged and
+     *   guest tries to use it with that drivers.
+     *
+     * Enable NUMA implicitly by adding a new NUMA node automatically.
+     */
+    if (ram_slots > 0 && QTAILQ_EMPTY(&numa_opts->head)) {
+        if (mc->auto_enable_numa_with_memhp) {
+            qemu_opts_parse_noisily(numa_opts, "node", true);
+        }
+    }
+
+    if (qemu_opts_foreach(numa_opts, parse_numa, ms, NULL)) {
         exit(1);
     }
 
diff --git a/vl.c b/vl.c
index 9bb5058..d083b4d 100644
--- a/vl.c
+++ b/vl.c
@@ -4665,7 +4665,11 @@ int main(int argc, char **argv, char **envp)
     default_drive(default_floppy, snapshot, IF_FLOPPY, 0, FD_OPTS);
     default_drive(default_sdcard, snapshot, IF_SD, 0, SD_OPTS);
 
-    parse_numa_opts(current_machine);
+    current_machine->ram_size = ram_size;
+    current_machine->maxram_size = maxram_size;
+    current_machine->ram_slots = ram_slots;
+
+    parse_numa_opts(current_machine, ram_slots);
 
     if (qemu_opts_foreach(qemu_find_opts("mon"),
                           mon_init_func, NULL, NULL)) {
@@ -4710,9 +4714,6 @@ int main(int argc, char **argv, char **envp)
     replay_checkpoint(CHECKPOINT_INIT);
     qdev_machine_init();
 
-    current_machine->ram_size = ram_size;
-    current_machine->maxram_size = maxram_size;
-    current_machine->ram_slots = ram_slots;
     current_machine->boot_order = boot_order;
     current_machine->cpu_model = cpu_model;
 
-- 
2.5.5

Re: [Qemu-devel] [PATCH v3] NUMA: Enable adding NUMA node implicitly

[Dou Liyang]

Hi all,

It seems that a month has passed

So, Ping...

Thanks,
	dou.

At 09/21/2017 05:23 PM, Dou Liyang wrote:
> Linux and Windows need ACPI SRAT table to make memory hotplug work properly,
> however currently QEMU doesn't create SRAT table if numa options aren't present
> on CLI.
>
> Which breaks both linux and windows guests in certain conditions:
>  * Windows: won't enable memory hotplug without SRAT table at all
>  * Linux: if QEMU is started with initial memory all below 4Gb and no SRAT table
>    present, guest kernel will use nommu DMA ops, which breaks 32bit hw drivers
>    when memory is hotplugged and guest tries to use it with that drivers.
>
> Fix above issues by automatically creating a numa node when QEMU is started with
> memory hotplug enabled but without '-numa' options on CLI.
> (PS: auto-create numa node only for new machine types so not to break migration).
>
> Which would provide SRAT table to guests without explicit -numa options on CLI
> and would allow:
>  * Windows: to enable memory hotplug
>  * Linux: switch to SWIOTLB DMA ops, to bounce DMA transfers to 32bit allocated
>    buffers that legacy drivers/hw can handle.
>
> [Rewritten by Igor]
>
> Reported-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
> Suggested-by: Igor Mammedov <imammedo@redhat.com>
> Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Richard Henderson <rth@twiddle.net>
> Cc: Eduardo Habkost <ehabkost@redhat.com>
> Cc: "Michael S. Tsirkin" <mst@redhat.com>
> Cc: Marcel Apfelbaum <marcel@redhat.com>
> Cc: Igor Mammedov <imammedo@redhat.com>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Thomas Huth <thuth@redhat.com>
> Cc: Alistair Francis <alistair23@gmail.com>
> Cc: f4bug@amsat.org
> Cc: Takao Indoh <indou.takao@jp.fujitsu.com>
> Cc: Izumi Taku <izumi.taku@jp.fujitsu.com>
> ---
> changelog V2 --> V3:
>   -Replace the callback function with a boolean parameter suggested by Igor
>   -Use QTAILQ_EMPTY() macro to check the QemuOptsList
>
>  hw/i386/pc.c          |  1 +
>  hw/i386/pc_piix.c     |  1 +
>  hw/i386/pc_q35.c      |  1 +
>  include/hw/boards.h   |  1 +
>  include/sysemu/numa.h |  2 +-
>  numa.c                | 24 ++++++++++++++++++++++--
>  vl.c                  |  9 +++++----
>  7 files changed, 32 insertions(+), 7 deletions(-)
>
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index 05985d4..f1a44cc 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -2318,6 +2318,7 @@ static void pc_machine_class_init(ObjectClass *oc, void *data)
>      mc->cpu_index_to_instance_props = pc_cpu_index_to_props;
>      mc->get_default_cpu_node_id = pc_get_default_cpu_node_id;
>      mc->possible_cpu_arch_ids = pc_possible_cpu_arch_ids;
> +    mc->auto_enable_numa_with_memhp = true;
>      mc->has_hotpluggable_cpus = true;
>      mc->default_boot_order = "cad";
>      mc->hot_add_cpu = pc_hot_add_cpu;
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index 9ff79b1..d87a433 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -449,6 +449,7 @@ static void pc_i440fx_2_10_machine_options(MachineClass *m)
>      m->is_default = 0;
>      m->alias = NULL;
>      SET_MACHINE_COMPAT(m, PC_COMPAT_2_10);
> +    m->auto_enable_numa_with_memhp = false;
>  }
>
>  DEFINE_I440FX_MACHINE(v2_10, "pc-i440fx-2.10", NULL,
> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> index 6c4ec4b..68cbfc5 100644
> --- a/hw/i386/pc_q35.c
> +++ b/hw/i386/pc_q35.c
> @@ -319,6 +319,7 @@ static void pc_q35_2_10_machine_options(MachineClass *m)
>      m->alias = NULL;
>      SET_MACHINE_COMPAT(m, PC_COMPAT_2_10);
>      m->numa_auto_assign_ram = numa_legacy_auto_assign_ram;
> +    m->auto_enable_numa_with_memhp = false;
>  }
>
>  DEFINE_Q35_MACHINE(v2_10, "pc-q35-2.10", NULL,
> diff --git a/include/hw/boards.h b/include/hw/boards.h
> index 156e0a5..0fe2c8f 100644
> --- a/include/hw/boards.h
> +++ b/include/hw/boards.h
> @@ -191,6 +191,7 @@ struct MachineClass {
>      bool has_hotpluggable_cpus;
>      bool ignore_memory_transaction_failures;
>      int numa_mem_align_shift;
> +    bool auto_enable_numa_with_memhp;
>      void (*numa_auto_assign_ram)(MachineClass *mc, NodeInfo *nodes,
>                                   int nb_nodes, ram_addr_t size);
>
> diff --git a/include/sysemu/numa.h b/include/sysemu/numa.h
> index 5c6df28..31d3ac0 100644
> --- a/include/sysemu/numa.h
> +++ b/include/sysemu/numa.h
> @@ -30,7 +30,7 @@ struct NumaNodeMem {
>  };
>
>  extern NodeInfo numa_info[MAX_NODES];
> -void parse_numa_opts(MachineState *ms);
> +void parse_numa_opts(MachineState *ms, uint64_t ram_slots);
>  void query_numa_node_mem(NumaNodeMem node_mem[]);
>  extern QemuOptsList qemu_numa_opts;
>  void numa_set_mem_node_id(ram_addr_t addr, uint64_t size, uint32_t node);
> diff --git a/numa.c b/numa.c
> index 100a67f..ba8d813 100644
> --- a/numa.c
> +++ b/numa.c
> @@ -423,12 +423,32 @@ void numa_default_auto_assign_ram(MachineClass *mc, NodeInfo *nodes,
>      nodes[i].node_mem = size - usedmem;
>  }
>
> -void parse_numa_opts(MachineState *ms)
> +void parse_numa_opts(MachineState *ms, uint64_t ram_slots)
>  {
>      int i;
>      MachineClass *mc = MACHINE_GET_CLASS(ms);
> +    QemuOptsList *numa_opts = qemu_find_opts("numa");
>
> -    if (qemu_opts_foreach(qemu_find_opts("numa"), parse_numa, ms, NULL)) {
> +    /*
> +     * If memory hotplug is enabled (slots > 0) but without '-numa'
> +     * options explicitly on CLI, guestes will break.
> +     *
> +     *   Windows: won't enable memory hotplug without SRAT table at all
> +     *
> +     *   Linux: if QEMU is started with initial memory all below 4Gb
> +     *   and no SRAT table present, guest kernel will use nommu DMA ops,
> +     *   which breaks 32bit hw drivers when memory is hotplugged and
> +     *   guest tries to use it with that drivers.
> +     *
> +     * Enable NUMA implicitly by adding a new NUMA node automatically.
> +     */
> +    if (ram_slots > 0 && QTAILQ_EMPTY(&numa_opts->head)) {
> +        if (mc->auto_enable_numa_with_memhp) {
> +            qemu_opts_parse_noisily(numa_opts, "node", true);
> +        }
> +    }
> +
> +    if (qemu_opts_foreach(numa_opts, parse_numa, ms, NULL)) {
>          exit(1);
>      }
>
> diff --git a/vl.c b/vl.c
> index 9bb5058..d083b4d 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -4665,7 +4665,11 @@ int main(int argc, char **argv, char **envp)
>      default_drive(default_floppy, snapshot, IF_FLOPPY, 0, FD_OPTS);
>      default_drive(default_sdcard, snapshot, IF_SD, 0, SD_OPTS);
>
> -    parse_numa_opts(current_machine);
> +    current_machine->ram_size = ram_size;
> +    current_machine->maxram_size = maxram_size;
> +    current_machine->ram_slots = ram_slots;
> +
> +    parse_numa_opts(current_machine, ram_slots);
>
>      if (qemu_opts_foreach(qemu_find_opts("mon"),
>                            mon_init_func, NULL, NULL)) {
> @@ -4710,9 +4714,6 @@ int main(int argc, char **argv, char **envp)
>      replay_checkpoint(CHECKPOINT_INIT);
>      qdev_machine_init();
>
> -    current_machine->ram_size = ram_size;
> -    current_machine->maxram_size = maxram_size;
> -    current_machine->ram_slots = ram_slots;
>      current_machine->boot_order = boot_order;
>      current_machine->cpu_model = cpu_model;
>
>

Re: [Qemu-devel] [PATCH v3] NUMA: Enable adding NUMA node implicitly

[Igor Mammedov]

On Thu, 21 Sep 2017 17:23:08 +0800
Dou Liyang <douly.fnst@cn.fujitsu.com> wrote:

> Linux and Windows need ACPI SRAT table to make memory hotplug work properly,
> however currently QEMU doesn't create SRAT table if numa options aren't present
> on CLI.
> 
> Which breaks both linux and windows guests in certain conditions:
>  * Windows: won't enable memory hotplug without SRAT table at all
>  * Linux: if QEMU is started with initial memory all below 4Gb and no SRAT table
>    present, guest kernel will use nommu DMA ops, which breaks 32bit hw drivers
>    when memory is hotplugged and guest tries to use it with that drivers.
> 
> Fix above issues by automatically creating a numa node when QEMU is started with
> memory hotplug enabled but without '-numa' options on CLI.
> (PS: auto-create numa node only for new machine types so not to break migration).
> 
> Which would provide SRAT table to guests without explicit -numa options on CLI
> and would allow:
>  * Windows: to enable memory hotplug
>  * Linux: switch to SWIOTLB DMA ops, to bounce DMA transfers to 32bit allocated
>    buffers that legacy drivers/hw can handle.
> 
> [Rewritten by Igor]
> 
> Reported-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
> Suggested-by: Igor Mammedov <imammedo@redhat.com>
> Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Richard Henderson <rth@twiddle.net>
> Cc: Eduardo Habkost <ehabkost@redhat.com>
> Cc: "Michael S. Tsirkin" <mst@redhat.com>
> Cc: Marcel Apfelbaum <marcel@redhat.com>
> Cc: Igor Mammedov <imammedo@redhat.com>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Thomas Huth <thuth@redhat.com>
> Cc: Alistair Francis <alistair23@gmail.com>
> Cc: f4bug@amsat.org
> Cc: Takao Indoh <indou.takao@jp.fujitsu.com>
> Cc: Izumi Taku <izumi.taku@jp.fujitsu.com>
> ---
> changelog V2 --> V3:
>   -Replace the callback function with a boolean parameter suggested by Igor
>   -Use QTAILQ_EMPTY() macro to check the QemuOptsList
> 
>  hw/i386/pc.c          |  1 +
>  hw/i386/pc_piix.c     |  1 +
>  hw/i386/pc_q35.c      |  1 +
>  include/hw/boards.h   |  1 +
>  include/sysemu/numa.h |  2 +-
>  numa.c                | 24 ++++++++++++++++++++++--
>  vl.c                  |  9 +++++----
>  7 files changed, 32 insertions(+), 7 deletions(-)
> 
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index 05985d4..f1a44cc 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -2318,6 +2318,7 @@ static void pc_machine_class_init(ObjectClass *oc, void *data)
>      mc->cpu_index_to_instance_props = pc_cpu_index_to_props;
>      mc->get_default_cpu_node_id = pc_get_default_cpu_node_id;
>      mc->possible_cpu_arch_ids = pc_possible_cpu_arch_ids;
> +    mc->auto_enable_numa_with_memhp = true;
>      mc->has_hotpluggable_cpus = true;
>      mc->default_boot_order = "cad";
>      mc->hot_add_cpu = pc_hot_add_cpu;
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index 9ff79b1..d87a433 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -449,6 +449,7 @@ static void pc_i440fx_2_10_machine_options(MachineClass *m)
>      m->is_default = 0;
>      m->alias = NULL;
>      SET_MACHINE_COMPAT(m, PC_COMPAT_2_10);
> +    m->auto_enable_numa_with_memhp = false;
>  }
>  
>  DEFINE_I440FX_MACHINE(v2_10, "pc-i440fx-2.10", NULL,
> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> index 6c4ec4b..68cbfc5 100644
> --- a/hw/i386/pc_q35.c
> +++ b/hw/i386/pc_q35.c
> @@ -319,6 +319,7 @@ static void pc_q35_2_10_machine_options(MachineClass *m)
>      m->alias = NULL;
>      SET_MACHINE_COMPAT(m, PC_COMPAT_2_10);
>      m->numa_auto_assign_ram = numa_legacy_auto_assign_ram;
> +    m->auto_enable_numa_with_memhp = false;
>  }
>  
>  DEFINE_Q35_MACHINE(v2_10, "pc-q35-2.10", NULL,
> diff --git a/include/hw/boards.h b/include/hw/boards.h
> index 156e0a5..0fe2c8f 100644
> --- a/include/hw/boards.h
> +++ b/include/hw/boards.h
> @@ -191,6 +191,7 @@ struct MachineClass {
>      bool has_hotpluggable_cpus;
>      bool ignore_memory_transaction_failures;
>      int numa_mem_align_shift;
> +    bool auto_enable_numa_with_memhp;
>      void (*numa_auto_assign_ram)(MachineClass *mc, NodeInfo *nodes,
>                                   int nb_nodes, ram_addr_t size);
>  
> diff --git a/include/sysemu/numa.h b/include/sysemu/numa.h
> index 5c6df28..31d3ac0 100644
> --- a/include/sysemu/numa.h
> +++ b/include/sysemu/numa.h
> @@ -30,7 +30,7 @@ struct NumaNodeMem {
>  };
>  
>  extern NodeInfo numa_info[MAX_NODES];
> -void parse_numa_opts(MachineState *ms);
> +void parse_numa_opts(MachineState *ms, uint64_t ram_slots);
>  void query_numa_node_mem(NumaNodeMem node_mem[]);
>  extern QemuOptsList qemu_numa_opts;
>  void numa_set_mem_node_id(ram_addr_t addr, uint64_t size, uint32_t node);
> diff --git a/numa.c b/numa.c
> index 100a67f..ba8d813 100644
> --- a/numa.c
> +++ b/numa.c
> @@ -423,12 +423,32 @@ void numa_default_auto_assign_ram(MachineClass *mc, NodeInfo *nodes,
>      nodes[i].node_mem = size - usedmem;
>  }
>  
> -void parse_numa_opts(MachineState *ms)
> +void parse_numa_opts(MachineState *ms, uint64_t ram_slots)
>  {
>      int i;
>      MachineClass *mc = MACHINE_GET_CLASS(ms);
> +    QemuOptsList *numa_opts = qemu_find_opts("numa");
>  
> -    if (qemu_opts_foreach(qemu_find_opts("numa"), parse_numa, ms, NULL)) {
> +    /*
> +     * If memory hotplug is enabled (slots > 0) but without '-numa'
> +     * options explicitly on CLI, guestes will break.
> +     *
> +     *   Windows: won't enable memory hotplug without SRAT table at all
> +     *
> +     *   Linux: if QEMU is started with initial memory all below 4Gb
> +     *   and no SRAT table present, guest kernel will use nommu DMA ops,
> +     *   which breaks 32bit hw drivers when memory is hotplugged and
> +     *   guest tries to use it with that drivers.
> +     *
> +     * Enable NUMA implicitly by adding a new NUMA node automatically.
> +     */
> +    if (ram_slots > 0 && QTAILQ_EMPTY(&numa_opts->head)) {
> +        if (mc->auto_enable_numa_with_memhp) {
> +            qemu_opts_parse_noisily(numa_opts, "node", true);
> +        }
> +    }
> +
> +    if (qemu_opts_foreach(numa_opts, parse_numa, ms, NULL)) {
>          exit(1);
>      }
>  
> diff --git a/vl.c b/vl.c
> index 9bb5058..d083b4d 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -4665,7 +4665,11 @@ int main(int argc, char **argv, char **envp)
>      default_drive(default_floppy, snapshot, IF_FLOPPY, 0, FD_OPTS);
>      default_drive(default_sdcard, snapshot, IF_SD, 0, SD_OPTS);
>  
> -    parse_numa_opts(current_machine);
> +    current_machine->ram_size = ram_size;
> +    current_machine->maxram_size = maxram_size;
> +    current_machine->ram_slots = ram_slots;
> +
> +    parse_numa_opts(current_machine, ram_slots);
>  
>      if (qemu_opts_foreach(qemu_find_opts("mon"),
>                            mon_init_func, NULL, NULL)) {
> @@ -4710,9 +4714,6 @@ int main(int argc, char **argv, char **envp)
>      replay_checkpoint(CHECKPOINT_INIT);
>      qdev_machine_init();
>  
> -    current_machine->ram_size = ram_size;
> -    current_machine->maxram_size = maxram_size;
> -    current_machine->ram_slots = ram_slots;
>      current_machine->boot_order = boot_order;
>      current_machine->cpu_model = cpu_model;
it should be safe to move parse_numa_opts(current_machine) here

  

Re: [Qemu-devel] [PATCH v3] NUMA: Enable adding NUMA node implicitly

[Dou Liyang]

Hi Igor,

>> diff --git a/vl.c b/vl.c
>> index 9bb5058..d083b4d 100644
>> --- a/vl.c
>> +++ b/vl.c
>> @@ -4665,7 +4665,11 @@ int main(int argc, char **argv, char **envp)
>>      default_drive(default_floppy, snapshot, IF_FLOPPY, 0, FD_OPTS);
>>      default_drive(default_sdcard, snapshot, IF_SD, 0, SD_OPTS);
>>
>> -    parse_numa_opts(current_machine);
>> +    current_machine->ram_size = ram_size;
>> +    current_machine->maxram_size = maxram_size;
>> +    current_machine->ram_slots = ram_slots;
>> +
>> +    parse_numa_opts(current_machine, ram_slots);
>>
>>      if (qemu_opts_foreach(qemu_find_opts("mon"),
>>                            mon_init_func, NULL, NULL)) {
>> @@ -4710,9 +4714,6 @@ int main(int argc, char **argv, char **envp)
>>      replay_checkpoint(CHECKPOINT_INIT);
>>      qdev_machine_init();
>>
>> -    current_machine->ram_size = ram_size;
>> -    current_machine->maxram_size = maxram_size;
>> -    current_machine->ram_slots = ram_slots;
>>      current_machine->boot_order = boot_order;
>>      current_machine->cpu_model = cpu_model;
> it should be safe to move parse_numa_opts(current_machine) here
>

Yes, Indeed!

I have modified and tested this, It's good. will change in the next
version.

Thanks,
	dou.

>
>
>
>
>