xl: introduce specific VCPU to PCPU mapping in config file

xm supports the following syntax (in the config file) for
specific VCPU to PCPU mapping:

cpus = "0-3,5,^1" # all vcpus run on cpus 0,2,3,5
cpus = ["2", "3"] # VCPU0 runs on CPU2, VCPU1 runs on CPU3

Allow for the same in xl.

This fixes what happened in changeset 54000bca7a6a, which
introduced suppot for the `cpus=` option within xl, but used
both the list (cpus=[2, 3]) and the string (cpus="2,3") syntax
for achieving the same behaviour (pin all guest's vcpus to the
pcpus in the list/string).

Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>

1 files changed, 19 insertions, 7 deletions

diff --git a/docs/man/xl.cfg.pod.5 b/docs/man/xl.cfg.pod.5
index 64baf38f74..832bae4cb9 100644
--- a/docs/man/xl.cfg.pod.5
+++ b/docs/man/xl.cfg.pod.5
@@ -108,9 +108,25 @@ created online and the remainder will be offline.
 =item B<cpus="CPU-LIST">
 
 List of which cpus the guest is allowed to use. Default behavior is
-`all cpus`. A list of cpus may be specified as follows: `cpus="0-3,5,^1"`
-(all vcpus will run on cpus 0,2,3,5), or `cpus=["2", "3"]` (all vcpus
-will run on cpus 2 and 3).
+`all cpus`. A C<CPU-LIST> may be specified as follows:
+
+=over 4
+
+=item "all"
+
+To allow all the vcpus of the guest to run on all the cpus on the host.
+
+=item "0-3,5,^1"
+
+To allow all the vcpus of the guest to run on cpus 0,2,3,5.
+
+=item ["2", "3"] (or [2, 3])
+
+To ask for specific vcpu mapping. That means (in this example), vcpu #0
+of the guest will run on cpu #2 of the host and vcpu #1 of the guest will
+run on cpu #3 of the host.
+
+=back
 
 =item B<cpu_weight=WEIGHT>
 
@@ -951,10 +967,6 @@ XXX
 
 XXX
 
-=item B<cpus=XXX>
-
-XXX
-
 =item B<maxmem=NUMBER>
 
 XXX