qemu-devel.nongnu.org archive mirror
 help / color / mirror / Atom feed
* [PATCH] hw/arm/virt: Expose empty NUMA nodes through ACPI
@ 2021-10-25 23:41 Gavin Shan
  2021-10-26  6:25 ` Andrew Jones
  2021-10-26  9:47 ` Igor Mammedov
  0 siblings, 2 replies; 6+ messages in thread
From: Gavin Shan @ 2021-10-25 23:41 UTC (permalink / raw)
  To: qemu-arm
  Cc: peter.maydell, drjones, ehabkost, richard.henderson, qemu-devel,
	shan.gavin

The empty NUMA nodes, where no memory resides, aren't exposed
through ACPI SRAT table. It's not user preferred behaviour because
the corresponding memory node devices are missed from the guest
kernel as the following example shows, and memory can't be hot
added to these empty NUMA nodes at later point.

  /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \
  -accel kvm -machine virt,gic-version=host               \
  -cpu host -smp 4,sockets=2,cores=2,threads=1            \
  -m 1024M,slots=16,maxmem=64G                            \
  -object memory-backend-ram,id=mem0,size=512M            \
  -object memory-backend-ram,id=mem1,size=512M            \
  -numa node,nodeid=0,cpus=0-1,memdev=mem0                \
  -numa node,nodeid=1,cpus=2-3,memdev=mem1                \
  -numa node,nodeid=2                                     \
  -numa node,nodeid=3                                     \
     :
  guest# ls /sys/devices/system/node | grep node
  node0
  node1
  node2

This exposes these empty NUMA nodes through ACPI SRAT table. With
this applied, the corresponding memory node devices can be found
from the guest. Note that the hotpluggable capability is explicitly
given to these empty NUMA nodes for sake of completeness.

  guest# ls /sys/devices/system/node | grep node
  node0
  node1
  node2
  node3

Signed-off-by: Gavin Shan <gshan@redhat.com>
---
 hw/arm/virt-acpi-build.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
index 674f902652..a4c95b2f64 100644
--- a/hw/arm/virt-acpi-build.c
+++ b/hw/arm/virt-acpi-build.c
@@ -526,6 +526,7 @@ build_srat(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
     const CPUArchIdList *cpu_list = mc->possible_cpu_arch_ids(ms);
     AcpiTable table = { .sig = "SRAT", .rev = 3, .oem_id = vms->oem_id,
                         .oem_table_id = vms->oem_table_id };
+    MemoryAffinityFlags flags;
 
     acpi_table_begin(&table, table_data);
     build_append_int_noprefix(table_data, 1, 4); /* Reserved */
@@ -547,12 +548,15 @@ build_srat(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
 
     mem_base = vms->memmap[VIRT_MEM].base;
     for (i = 0; i < ms->numa_state->num_nodes; ++i) {
-        if (ms->numa_state->nodes[i].node_mem > 0) {
-            build_srat_memory(table_data, mem_base,
-                              ms->numa_state->nodes[i].node_mem, i,
-                              MEM_AFFINITY_ENABLED);
-            mem_base += ms->numa_state->nodes[i].node_mem;
+        if (ms->numa_state->nodes[i].node_mem) {
+            flags = MEM_AFFINITY_ENABLED;
+        } else {
+            flags = MEM_AFFINITY_ENABLED | MEM_AFFINITY_HOTPLUGGABLE;
         }
+
+        build_srat_memory(table_data, mem_base,
+                          ms->numa_state->nodes[i].node_mem, i, flags);
+        mem_base += ms->numa_state->nodes[i].node_mem;
     }
 
     if (ms->nvdimms_state->is_enabled) {
-- 
2.23.0



^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH] hw/arm/virt: Expose empty NUMA nodes through ACPI
  2021-10-25 23:41 [PATCH] hw/arm/virt: Expose empty NUMA nodes through ACPI Gavin Shan
@ 2021-10-26  6:25 ` Andrew Jones
  2021-10-27  5:16   ` Gavin Shan
  2021-10-26  9:47 ` Igor Mammedov
  1 sibling, 1 reply; 6+ messages in thread
From: Andrew Jones @ 2021-10-26  6:25 UTC (permalink / raw)
  To: Gavin Shan
  Cc: peter.maydell, ehabkost, richard.henderson, qemu-devel, qemu-arm,
	shan.gavin

On Tue, Oct 26, 2021 at 07:41:01AM +0800, Gavin Shan wrote:
> The empty NUMA nodes, where no memory resides, aren't exposed
> through ACPI SRAT table. It's not user preferred behaviour because
> the corresponding memory node devices are missed from the guest
> kernel as the following example shows, and memory can't be hot
> added to these empty NUMA nodes at later point.
> 
>   /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \
>   -accel kvm -machine virt,gic-version=host               \
>   -cpu host -smp 4,sockets=2,cores=2,threads=1            \
>   -m 1024M,slots=16,maxmem=64G                            \
>   -object memory-backend-ram,id=mem0,size=512M            \
>   -object memory-backend-ram,id=mem1,size=512M            \
>   -numa node,nodeid=0,cpus=0-1,memdev=mem0                \
>   -numa node,nodeid=1,cpus=2-3,memdev=mem1                \
>   -numa node,nodeid=2                                     \
>   -numa node,nodeid=3                                     \
>      :
>   guest# ls /sys/devices/system/node | grep node
>   node0
>   node1
>   node2

node2 shouldn't be in this list, should it?

> 
> This exposes these empty NUMA nodes through ACPI SRAT table. With
> this applied, the corresponding memory node devices can be found
> from the guest. Note that the hotpluggable capability is explicitly
> given to these empty NUMA nodes for sake of completeness.
> 
>   guest# ls /sys/devices/system/node | grep node
>   node0
>   node1
>   node2
>   node3
> 
> Signed-off-by: Gavin Shan <gshan@redhat.com>
> ---
>  hw/arm/virt-acpi-build.c | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
> index 674f902652..a4c95b2f64 100644
> --- a/hw/arm/virt-acpi-build.c
> +++ b/hw/arm/virt-acpi-build.c
> @@ -526,6 +526,7 @@ build_srat(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
>      const CPUArchIdList *cpu_list = mc->possible_cpu_arch_ids(ms);
>      AcpiTable table = { .sig = "SRAT", .rev = 3, .oem_id = vms->oem_id,
>                          .oem_table_id = vms->oem_table_id };
> +    MemoryAffinityFlags flags;
>  
>      acpi_table_begin(&table, table_data);
>      build_append_int_noprefix(table_data, 1, 4); /* Reserved */
> @@ -547,12 +548,15 @@ build_srat(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
>  
>      mem_base = vms->memmap[VIRT_MEM].base;
>      for (i = 0; i < ms->numa_state->num_nodes; ++i) {
> -        if (ms->numa_state->nodes[i].node_mem > 0) {
> -            build_srat_memory(table_data, mem_base,
> -                              ms->numa_state->nodes[i].node_mem, i,
> -                              MEM_AFFINITY_ENABLED);
> -            mem_base += ms->numa_state->nodes[i].node_mem;
> +        if (ms->numa_state->nodes[i].node_mem) {
> +            flags = MEM_AFFINITY_ENABLED;
> +        } else {
> +            flags = MEM_AFFINITY_ENABLED | MEM_AFFINITY_HOTPLUGGABLE;
>          }
> +
> +        build_srat_memory(table_data, mem_base,
> +                          ms->numa_state->nodes[i].node_mem, i, flags);
> +        mem_base += ms->numa_state->nodes[i].node_mem;
>      }
>  
>      if (ms->nvdimms_state->is_enabled) {
> -- 
> 2.23.0
>

Besides the possible issue with the commit message,

Reviewed-by: Andrew Jones <drjones@redhat.com>

Thanks,
drew



^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] hw/arm/virt: Expose empty NUMA nodes through ACPI
  2021-10-25 23:41 [PATCH] hw/arm/virt: Expose empty NUMA nodes through ACPI Gavin Shan
  2021-10-26  6:25 ` Andrew Jones
@ 2021-10-26  9:47 ` Igor Mammedov
  2021-10-27  5:20   ` Gavin Shan
  1 sibling, 1 reply; 6+ messages in thread
From: Igor Mammedov @ 2021-10-26  9:47 UTC (permalink / raw)
  To: Gavin Shan
  Cc: peter.maydell, drjones, ehabkost, richard.henderson, qemu-devel,
	qemu-arm, shan.gavin

On Tue, 26 Oct 2021 07:41:01 +0800
Gavin Shan <gshan@redhat.com> wrote:

> The empty NUMA nodes, where no memory resides, aren't exposed
> through ACPI SRAT table. It's not user preferred behaviour because
> the corresponding memory node devices are missed from the guest
> kernel as the following example shows, and memory can't be hot
> added to these empty NUMA nodes at later point.

a error message one gets would be useful here.

btw:
memory hotplug seems to work for x86 without adding empty nodes.
So it beg a question, if absence of empty nodes is the issue here.

> 
>   /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \
>   -accel kvm -machine virt,gic-version=host               \
>   -cpu host -smp 4,sockets=2,cores=2,threads=1            \
>   -m 1024M,slots=16,maxmem=64G                            \
>   -object memory-backend-ram,id=mem0,size=512M            \
>   -object memory-backend-ram,id=mem1,size=512M            \
>   -numa node,nodeid=0,cpus=0-1,memdev=mem0                \
>   -numa node,nodeid=1,cpus=2-3,memdev=mem1                \
>   -numa node,nodeid=2                                     \
>   -numa node,nodeid=3                                     \
>      :
>   guest# ls /sys/devices/system/node | grep node
>   node0
>   node1
>   node2
> 
> This exposes these empty NUMA nodes through ACPI SRAT table. With
> this applied, the corresponding memory node devices can be found
> from the guest. Note that the hotpluggable capability is explicitly
> given to these empty NUMA nodes for sake of completeness.
> 
>   guest# ls /sys/devices/system/node | grep node
>   node0
>   node1
>   node2
>   node3
> 
> Signed-off-by: Gavin Shan <gshan@redhat.com>
> ---
>  hw/arm/virt-acpi-build.c | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
> index 674f902652..a4c95b2f64 100644
> --- a/hw/arm/virt-acpi-build.c
> +++ b/hw/arm/virt-acpi-build.c
> @@ -526,6 +526,7 @@ build_srat(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
>      const CPUArchIdList *cpu_list = mc->possible_cpu_arch_ids(ms);
>      AcpiTable table = { .sig = "SRAT", .rev = 3, .oem_id = vms->oem_id,
>                          .oem_table_id = vms->oem_table_id };
> +    MemoryAffinityFlags flags;
>  
>      acpi_table_begin(&table, table_data);
>      build_append_int_noprefix(table_data, 1, 4); /* Reserved */
> @@ -547,12 +548,15 @@ build_srat(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
>  
>      mem_base = vms->memmap[VIRT_MEM].base;
>      for (i = 0; i < ms->numa_state->num_nodes; ++i) {
> -        if (ms->numa_state->nodes[i].node_mem > 0) {
> -            build_srat_memory(table_data, mem_base,
> -                              ms->numa_state->nodes[i].node_mem, i,
> -                              MEM_AFFINITY_ENABLED);
> -            mem_base += ms->numa_state->nodes[i].node_mem;
> +        if (ms->numa_state->nodes[i].node_mem) {
> +            flags = MEM_AFFINITY_ENABLED;
> +        } else {
> +            flags = MEM_AFFINITY_ENABLED | MEM_AFFINITY_HOTPLUGGABLE;
>          }
> +
> +        build_srat_memory(table_data, mem_base,
> +                          ms->numa_state->nodes[i].node_mem, i, flags);
> +        mem_base += ms->numa_state->nodes[i].node_mem;
>      }
>  
>      if (ms->nvdimms_state->is_enabled) {



^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] hw/arm/virt: Expose empty NUMA nodes through ACPI
  2021-10-26  6:25 ` Andrew Jones
@ 2021-10-27  5:16   ` Gavin Shan
  0 siblings, 0 replies; 6+ messages in thread
From: Gavin Shan @ 2021-10-27  5:16 UTC (permalink / raw)
  To: Andrew Jones
  Cc: peter.maydell, ehabkost, richard.henderson, qemu-devel, qemu-arm,
	shan.gavin

On 10/26/21 5:25 PM, Andrew Jones wrote:
> On Tue, Oct 26, 2021 at 07:41:01AM +0800, Gavin Shan wrote:
>> The empty NUMA nodes, where no memory resides, aren't exposed
>> through ACPI SRAT table. It's not user preferred behaviour because
>> the corresponding memory node devices are missed from the guest
>> kernel as the following example shows, and memory can't be hot
>> added to these empty NUMA nodes at later point.
>>
>>    /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \
>>    -accel kvm -machine virt,gic-version=host               \
>>    -cpu host -smp 4,sockets=2,cores=2,threads=1            \
>>    -m 1024M,slots=16,maxmem=64G                            \
>>    -object memory-backend-ram,id=mem0,size=512M            \
>>    -object memory-backend-ram,id=mem1,size=512M            \
>>    -numa node,nodeid=0,cpus=0-1,memdev=mem0                \
>>    -numa node,nodeid=1,cpus=2-3,memdev=mem1                \
>>    -numa node,nodeid=2                                     \
>>    -numa node,nodeid=3                                     \
>>       :
>>    guest# ls /sys/devices/system/node | grep node
>>    node0
>>    node1
>>    node2
> 
> node2 shouldn't be in this list, should it?
> 

Yes, the list shouldn't include node2. I'll amend the commit
log in v2.

>>
>> This exposes these empty NUMA nodes through ACPI SRAT table. With
>> this applied, the corresponding memory node devices can be found
>> from the guest. Note that the hotpluggable capability is explicitly
>> given to these empty NUMA nodes for sake of completeness.
>>
>>    guest# ls /sys/devices/system/node | grep node
>>    node0
>>    node1
>>    node2
>>    node3
>>
>> Signed-off-by: Gavin Shan <gshan@redhat.com>
>> ---
>>   hw/arm/virt-acpi-build.c | 14 +++++++++-----
>>   1 file changed, 9 insertions(+), 5 deletions(-)
>>
>> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
>> index 674f902652..a4c95b2f64 100644
>> --- a/hw/arm/virt-acpi-build.c
>> +++ b/hw/arm/virt-acpi-build.c
>> @@ -526,6 +526,7 @@ build_srat(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
>>       const CPUArchIdList *cpu_list = mc->possible_cpu_arch_ids(ms);
>>       AcpiTable table = { .sig = "SRAT", .rev = 3, .oem_id = vms->oem_id,
>>                           .oem_table_id = vms->oem_table_id };
>> +    MemoryAffinityFlags flags;
>>   
>>       acpi_table_begin(&table, table_data);
>>       build_append_int_noprefix(table_data, 1, 4); /* Reserved */
>> @@ -547,12 +548,15 @@ build_srat(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
>>   
>>       mem_base = vms->memmap[VIRT_MEM].base;
>>       for (i = 0; i < ms->numa_state->num_nodes; ++i) {
>> -        if (ms->numa_state->nodes[i].node_mem > 0) {
>> -            build_srat_memory(table_data, mem_base,
>> -                              ms->numa_state->nodes[i].node_mem, i,
>> -                              MEM_AFFINITY_ENABLED);
>> -            mem_base += ms->numa_state->nodes[i].node_mem;
>> +        if (ms->numa_state->nodes[i].node_mem) {
>> +            flags = MEM_AFFINITY_ENABLED;
>> +        } else {
>> +            flags = MEM_AFFINITY_ENABLED | MEM_AFFINITY_HOTPLUGGABLE;
>>           }
>> +
>> +        build_srat_memory(table_data, mem_base,
>> +                          ms->numa_state->nodes[i].node_mem, i, flags);
>> +        mem_base += ms->numa_state->nodes[i].node_mem;
>>       }
>>   
>>       if (ms->nvdimms_state->is_enabled) {
>> -- 
>> 2.23.0
>>
> 
> Besides the possible issue with the commit message,
> 
> Reviewed-by: Andrew Jones <drjones@redhat.com>
> 

Thanks,
Gavin



^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] hw/arm/virt: Expose empty NUMA nodes through ACPI
  2021-10-26  9:47 ` Igor Mammedov
@ 2021-10-27  5:20   ` Gavin Shan
  2021-10-27 14:31     ` Igor Mammedov
  0 siblings, 1 reply; 6+ messages in thread
From: Gavin Shan @ 2021-10-27  5:20 UTC (permalink / raw)
  To: Igor Mammedov
  Cc: peter.maydell, drjones, ehabkost, richard.henderson, qemu-devel,
	qemu-arm, shan.gavin

On 10/26/21 8:47 PM, Igor Mammedov wrote:
> On Tue, 26 Oct 2021 07:41:01 +0800
> Gavin Shan <gshan@redhat.com> wrote:
> 
>> The empty NUMA nodes, where no memory resides, aren't exposed
>> through ACPI SRAT table. It's not user preferred behaviour because
>> the corresponding memory node devices are missed from the guest
>> kernel as the following example shows, and memory can't be hot
>> added to these empty NUMA nodes at later point.
> 
> a error message one gets would be useful here.
> 
> btw:
> memory hotplug seems to work for x86 without adding empty nodes.
> So it beg a question, if absence of empty nodes is the issue here.
> 

Yes, the memory can be still hot added even the empty NUMA nodes
aren't exposed. However, we still need to expose them so that
the guest kernel has the information as the users specifies.

I will make the commit log more precise in v2.

>>
>>    /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \
>>    -accel kvm -machine virt,gic-version=host               \
>>    -cpu host -smp 4,sockets=2,cores=2,threads=1            \
>>    -m 1024M,slots=16,maxmem=64G                            \
>>    -object memory-backend-ram,id=mem0,size=512M            \
>>    -object memory-backend-ram,id=mem1,size=512M            \
>>    -numa node,nodeid=0,cpus=0-1,memdev=mem0                \
>>    -numa node,nodeid=1,cpus=2-3,memdev=mem1                \
>>    -numa node,nodeid=2                                     \
>>    -numa node,nodeid=3                                     \
>>       :
>>    guest# ls /sys/devices/system/node | grep node
>>    node0
>>    node1
>>    node2
>>
>> This exposes these empty NUMA nodes through ACPI SRAT table. With
>> this applied, the corresponding memory node devices can be found
>> from the guest. Note that the hotpluggable capability is explicitly
>> given to these empty NUMA nodes for sake of completeness.
>>
>>    guest# ls /sys/devices/system/node | grep node
>>    node0
>>    node1
>>    node2
>>    node3
>>
>> Signed-off-by: Gavin Shan <gshan@redhat.com>
>> ---
>>   hw/arm/virt-acpi-build.c | 14 +++++++++-----
>>   1 file changed, 9 insertions(+), 5 deletions(-)
>>
>> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
>> index 674f902652..a4c95b2f64 100644
>> --- a/hw/arm/virt-acpi-build.c
>> +++ b/hw/arm/virt-acpi-build.c
>> @@ -526,6 +526,7 @@ build_srat(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
>>       const CPUArchIdList *cpu_list = mc->possible_cpu_arch_ids(ms);
>>       AcpiTable table = { .sig = "SRAT", .rev = 3, .oem_id = vms->oem_id,
>>                           .oem_table_id = vms->oem_table_id };
>> +    MemoryAffinityFlags flags;
>>   
>>       acpi_table_begin(&table, table_data);
>>       build_append_int_noprefix(table_data, 1, 4); /* Reserved */
>> @@ -547,12 +548,15 @@ build_srat(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
>>   
>>       mem_base = vms->memmap[VIRT_MEM].base;
>>       for (i = 0; i < ms->numa_state->num_nodes; ++i) {
>> -        if (ms->numa_state->nodes[i].node_mem > 0) {
>> -            build_srat_memory(table_data, mem_base,
>> -                              ms->numa_state->nodes[i].node_mem, i,
>> -                              MEM_AFFINITY_ENABLED);
>> -            mem_base += ms->numa_state->nodes[i].node_mem;
>> +        if (ms->numa_state->nodes[i].node_mem) {
>> +            flags = MEM_AFFINITY_ENABLED;
>> +        } else {
>> +            flags = MEM_AFFINITY_ENABLED | MEM_AFFINITY_HOTPLUGGABLE;
>>           }
>> +
>> +        build_srat_memory(table_data, mem_base,
>> +                          ms->numa_state->nodes[i].node_mem, i, flags);
>> +        mem_base += ms->numa_state->nodes[i].node_mem;
>>       }
>>   
>>       if (ms->nvdimms_state->is_enabled) {
> 

Thanks,
Gavin



^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] hw/arm/virt: Expose empty NUMA nodes through ACPI
  2021-10-27  5:20   ` Gavin Shan
@ 2021-10-27 14:31     ` Igor Mammedov
  0 siblings, 0 replies; 6+ messages in thread
From: Igor Mammedov @ 2021-10-27 14:31 UTC (permalink / raw)
  To: Gavin Shan
  Cc: peter.maydell, drjones, ehabkost, richard.henderson, qemu-devel,
	qemu-arm, shan.gavin

On Wed, 27 Oct 2021 16:20:30 +1100
Gavin Shan <gshan@redhat.com> wrote:

> On 10/26/21 8:47 PM, Igor Mammedov wrote:
> > On Tue, 26 Oct 2021 07:41:01 +0800
> > Gavin Shan <gshan@redhat.com> wrote:
> >   
> >> The empty NUMA nodes, where no memory resides, aren't exposed
> >> through ACPI SRAT table. It's not user preferred behaviour because
> >> the corresponding memory node devices are missed from the guest
> >> kernel as the following example shows, and memory can't be hot
> >> added to these empty NUMA nodes at later point.  
> > 
> > a error message one gets would be useful here.
> > 
> > btw:
> > memory hotplug seems to work for x86 without adding empty nodes.
> > So it beg a question, if absence of empty nodes is the issue here.
> >   
> 
> Yes, the memory can be still hot added even the empty NUMA nodes
> aren't exposed. However, we still need to expose them so that
> the guest kernel has the information as the users specifies.

commit message says that memory can't be hotplugged though ...
so what doesn't work/is broken currently.

Question is why do we need to expose empty nodes
that aren't warranted by any present hardware (cpu/mem)?
(so far I see it as extra burden on qemu without any gain)

SRAT is typically used to describe startup configuration,
any changes to topology later during runtime are
made using _PXM objects.



> 
> I will make the commit log more precise in v2.
> 
> >>
> >>    /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \
> >>    -accel kvm -machine virt,gic-version=host               \
> >>    -cpu host -smp 4,sockets=2,cores=2,threads=1            \
> >>    -m 1024M,slots=16,maxmem=64G                            \
> >>    -object memory-backend-ram,id=mem0,size=512M            \
> >>    -object memory-backend-ram,id=mem1,size=512M            \
> >>    -numa node,nodeid=0,cpus=0-1,memdev=mem0                \
> >>    -numa node,nodeid=1,cpus=2-3,memdev=mem1                \
> >>    -numa node,nodeid=2                                     \
> >>    -numa node,nodeid=3                                     \
> >>       :
> >>    guest# ls /sys/devices/system/node | grep node
> >>    node0
> >>    node1
> >>    node2
> >>
> >> This exposes these empty NUMA nodes through ACPI SRAT table. With
> >> this applied, the corresponding memory node devices can be found
> >> from the guest. Note that the hotpluggable capability is explicitly
> >> given to these empty NUMA nodes for sake of completeness.
> >>
> >>    guest# ls /sys/devices/system/node | grep node
> >>    node0
> >>    node1
> >>    node2
> >>    node3
> >>
> >> Signed-off-by: Gavin Shan <gshan@redhat.com>
> >> ---
> >>   hw/arm/virt-acpi-build.c | 14 +++++++++-----
> >>   1 file changed, 9 insertions(+), 5 deletions(-)
> >>
> >> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
> >> index 674f902652..a4c95b2f64 100644
> >> --- a/hw/arm/virt-acpi-build.c
> >> +++ b/hw/arm/virt-acpi-build.c
> >> @@ -526,6 +526,7 @@ build_srat(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
> >>       const CPUArchIdList *cpu_list = mc->possible_cpu_arch_ids(ms);
> >>       AcpiTable table = { .sig = "SRAT", .rev = 3, .oem_id = vms->oem_id,
> >>                           .oem_table_id = vms->oem_table_id };
> >> +    MemoryAffinityFlags flags;
> >>   
> >>       acpi_table_begin(&table, table_data);
> >>       build_append_int_noprefix(table_data, 1, 4); /* Reserved */
> >> @@ -547,12 +548,15 @@ build_srat(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
> >>   
> >>       mem_base = vms->memmap[VIRT_MEM].base;
> >>       for (i = 0; i < ms->numa_state->num_nodes; ++i) {
> >> -        if (ms->numa_state->nodes[i].node_mem > 0) {
> >> -            build_srat_memory(table_data, mem_base,
> >> -                              ms->numa_state->nodes[i].node_mem, i,
> >> -                              MEM_AFFINITY_ENABLED);
> >> -            mem_base += ms->numa_state->nodes[i].node_mem;
> >> +        if (ms->numa_state->nodes[i].node_mem) {
> >> +            flags = MEM_AFFINITY_ENABLED;
> >> +        } else {
> >> +            flags = MEM_AFFINITY_ENABLED | MEM_AFFINITY_HOTPLUGGABLE;
> >>           }
> >> +
> >> +        build_srat_memory(table_data, mem_base,
> >> +                          ms->numa_state->nodes[i].node_mem, i, flags);
> >> +        mem_base += ms->numa_state->nodes[i].node_mem;
> >>       }
> >>   
> >>       if (ms->nvdimms_state->is_enabled) {  
> >   
> 
> Thanks,
> Gavin
> 



^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2021-10-27 15:17 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-10-25 23:41 [PATCH] hw/arm/virt: Expose empty NUMA nodes through ACPI Gavin Shan
2021-10-26  6:25 ` Andrew Jones
2021-10-27  5:16   ` Gavin Shan
2021-10-26  9:47 ` Igor Mammedov
2021-10-27  5:20   ` Gavin Shan
2021-10-27 14:31     ` Igor Mammedov

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).