The "Memory Proximity Domain Attributes" structure of the ACPI HMAT
has a "Processor Proximity Domain Valid" flag that is currently
always set because Qemu -numa requires an initiator=X value
when hmat=on. Unsetting this flag allows to create more complex
memory topologies by having multiple best initiators for a single
memory target.
This patch allows -numa without initiator=X when hmat=on by keeping
the default value MAX_NODES in numa_state->nodes[i].initiator.
All places reading numa_state->nodes[i].initiator already check
whether it's different from MAX_NODES before using it.
Tested with
qemu-system-x86_64 -accel kvm \
-machine pc,hmat=on \
-drive if=pflash,format=raw,file=./OVMF.fd \
-drive media=disk,format=qcow2,file=efi.qcow2 \
-smp 4 \
-m 3G \
-object memory-backend-ram,size=1G,id=ram0 \
-object memory-backend-ram,size=1G,id=ram1 \
-object memory-backend-ram,size=1G,id=ram2 \
-numa node,nodeid=0,memdev=ram0,cpus=0-1 \
-numa node,nodeid=1,memdev=ram1,cpus=2-3 \
-numa node,nodeid=2,memdev=ram2 \
-numa
hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=10
\
-numa
hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=10485760
\
-numa
hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=20
\
-numa
hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=5242880
\
-numa
hmat-lb,initiator=0,target=2,hierarchy=memory,data-type=access-latency,latency=30
\
-numa
hmat-lb,initiator=0,target=2,hierarchy=memory,data-type=access-bandwidth,bandwidth=1048576
\
-numa
hmat-lb,initiator=1,target=0,hierarchy=memory,data-type=access-latency,latency=20
\
-numa
hmat-lb,initiator=1,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=5242880
\
-numa
hmat-lb,initiator=1,target=1,hierarchy=memory,data-type=access-latency,latency=10
\
-numa
hmat-lb,initiator=1,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=10485760
\
-numa
hmat-lb,initiator=1,target=2,hierarchy=memory,data-type=access-latency,latency=30
\
-numa
hmat-lb,initiator=1,target=2,hierarchy=memory,data-type=access-bandwidth,bandwidth=1048576
which reports NUMA node2 at same distance from both node0 and node1 as seen in
lstopo:
Machine (2966MB total) + Package P#0
NUMANode P#2 (979MB)
Group0
NUMANode P#0 (980MB)
Core P#0 + PU P#0
Core P#1 + PU P#1
Group0
NUMANode P#1 (1007MB)
Core P#2 + PU P#2
Core P#3 + PU P#3
Before this patch, we had to add ",initiator=X" to "-numa
node,nodeid=2,memdev=ram2".
The lstopo output difference between initiator=1 and no initiator is:
@@ -1,10 +1,10 @@
Machine (2966MB total) + Package P#0
+ NUMANode P#2 (979MB)
Group0
NUMANode P#0 (980MB)
Core P#0 + PU P#0
Core P#1 + PU P#1
Group0
NUMANode P#1 (1007MB)
-NUMANode P#2 (979MB)
Core P#2 + PU P#2
Core P#3 + PU P#3
Corresponding changes in the HMAT MPDA structure:
@@ -49,10 +49,10 @@
[078h 0120 2] Structure Type : [Memory Proximity Domain
Attributes]
[07Ah 0122 2] Reserved :
[07Ch 0124 4] Length : 0028
-[080h 0128 2]Flags (decoded below) : 0001
-Processor Proximity Domain Valid : 1
+[080h 0128 2]Flags (decoded below) :
+Processor Proximity Domain Valid : 0
[082h 0130 2]Reserved1 :
-[084h 0132 4] Attached Initiator Proximity Domain : 0001
+[084h 0132 4] Attached Initiator Proximity Domain : 0080
[088h 0136 4] Memory Proximity Domain : 0002
[08Ch 0140 4]Reserved2 :
[090h 0144 8]Reserved3 :
Final HMAT SLLB structures:
[0A0h 0160 2] Structure Type : 0001 [System Locality Latency
and Bandwidth Information]
[0A2h 0162 2] Reserved :
[0A4h 0164 4] Length : 0040
[0A8h 0168 1]Flags (decoded below) : 00
Memory Hierarchy : 0
[0A9h 0169 1]Data Type : 00
[0AAh 0170 2]Reserved1 :
[0ACh 0172 4] Initiator Proximity Domains # : 0002
[0B0h 0176 4] Target Proximity Domains # : 0003
[0B4h 0180 4]Reserved2 :
[0B8h 0184 8] Entry Base Unit : 2710
[0C0h 0192 4] Initiator Proximity Domain List :
[0C4h 0196 4] Initiator Proximity Domain List : 0001
[0C8h 0200 4] Target Proximity Domain List :
[0CCh 0204 4] Target Proximity Domain List : 0001
[0D0h 0208 4] Target Proximity Domain List : 0002
[0D4h 0212 2]Entry : 0001
[0D6h 0214 2]Entry : 0002
[0D8h 0216 2]Entry : 0003
[0DAh 0218 2]Entry : 0002
[0DCh 0220 2]Entry : 0001
