numa: add '-numa cpu,...' option for property based node mapping

legacy cpu to node mapping is using cpu index values to map
VCPU to node with help of '-numa node,nodeid=node,cpus=x[-y]'
option. However cpu index is internal concept and QEMU users
have to guess /reimplement qemu's logic/ to map it to
a concrete cpu socket/core/thread to make sane CPUs
placement across numa nodes.

This patch allows to map cpu objects to numa nodes using
the same properties as used for cpus with -device/device_add
(socket-id/core-id/thread-id/node-id).

At present valid properties/values to address CPUs could be
fetched using hotpluggable-cpus monitor/qmp command, it will
require user to start qemu twice when creating domain to fetch
possible CPUs for a machine type/-smp layout first and
then the second time with numa explicit mapping for actual
usage. The first step results could be saved and reused to
set/change mapping later as far as machine type/-smp stays
the same.

Proposed impl. supports exact and wildcard matching to
simplify CLI and allow to set mapping for a specific cpu
or group of cpu objects specified by matched properties.

For example:

   # exact mapping x86
   -numa cpu,node-id=x,socket-id=y,core-id=z,thread-id=n

   # exact mapping SPAPR
   -numa cpu,node-id=x,core-id=y

   # wildcard mapping, all cpu objects that match socket-id=y
   # are mapped to node-id=x
   -numa cpu,node-id=x,socket-id=y

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <1494415802-227633-18-git-send-email-imammedo@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/qemu-options.hx b/qemu-options.hx
index e10c1454d1..6ffa98097d 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -145,10 +145,12 @@ STEXI
 @item -numa node[,mem=@var{size}][,cpus=@var{firstcpu}[-@var{lastcpu}]][,nodeid=@var{node}]
 @itemx -numa node[,memdev=@var{id}][,cpus=@var{firstcpu}[-@var{lastcpu}]][,nodeid=@var{node}]
 @itemx -numa dist,src=@var{source},dst=@var{destination},val=@var{distance}
+@itemx -numa cpu,node-id=@var{node}[,socket-id=@var{x}][,core-id=@var{y}][,thread-id=@var{z}]
 @findex -numa
 Define a NUMA node and assign RAM and VCPUs to it.
 Set the NUMA distance from a source node to a destination node.
 
+Legacy VCPU assignment uses @samp{cpus} option where
 @var{firstcpu} and @var{lastcpu} are CPU indexes. Each
 @samp{cpus} option represent a contiguous range of CPU indexes
 (or a single VCPU if @var{lastcpu} is omitted). A non-contiguous
@@ -162,6 +164,24 @@ a NUMA node:
 -numa node,cpus=0-2,cpus=5
 @end example
 
+@samp{cpu} option is a new alternative to @samp{cpus} option
+which uses @samp{socket-id|core-id|thread-id} properties to assign
+CPU objects to a @var{node} using topology layout properties of CPU.
+The set of properties is machine specific, and depends on used
+machine type/@samp{smp} options. It could be queried with
+@samp{hotpluggable-cpus} monitor command.
+@samp{node-id} property specifies @var{node} to which CPU object
+will be assigned, it's required for @var{node} to be declared
+with @samp{node} option before it's used with @samp{cpu} option.
+
+For example:
+@example
+-M pc \
+-smp 1,sockets=2,maxcpus=2 \
+-numa node,nodeid=0 -numa node,nodeid=1 \
+-numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1
+@end example
+
 @samp{mem} assigns a given RAM amount to a node. @samp{memdev}
 assigns RAM from a given memory backend device to a node. If
 @samp{mem} and @samp{memdev} are omitted in all nodes, RAM is