On Mon, Mar 22, 2021 at 10:52:02AM +0000, Peter Maydell wrote:
> On Thu, 18 Mar 2021 at 09:30, Daniel P. Berrangé <berra...@redhat.com> wrote:
> > ----------------------------------------------------------------
> > Remove many old deprecated features
> >
> > The following features have been deprecated for well over the 2
> > release cycle we promise
> >
> > ``-drive file=json:{...{'driver':'file'}}`` (since 3.0)
> > ``-vnc acl`` (since 4.0.0)
> > ``-mon ...,control=readline,pretty=on|off`` (since 4.1)
> > ``migrate_set_downtime`` and ``migrate_set_speed`` (since 2.8.0)
> > ``query-named-block-nodes`` result ``encryption_key_missing`` (since
> > 2.10.0)
> > ``query-block`` result ``inserted.encryption_key_missing`` (since 2.10.0)
> > ``migrate-set-cache-size`` and ``query-migrate-cache-size`` (since 2.11.0)
> > ``query-named-block-nodes`` and ``query-block`` result
> > dirty-bitmaps[i].status (since 4.0)
> > ``query-cpus`` (since 2.12.0)
> > ``query-cpus-fast`` ``arch`` output member (since 3.0.0)
> > ``query-events`` (since 4.0)
> > chardev client socket with ``wait`` option (since 4.0)
> > ``acl_show``, ``acl_reset``, ``acl_policy``, ``acl_add``, ``acl_remove``
> > (since 4.0.0)
> > ``ide-drive`` (since 4.2)
> > ``scsi-disk`` (since 4.2)
>
> Just FYI, it turns out that removing 'query-cpus' has broken Xen,
> whose libxl control library is still using it:
>
> https://lists.xenproject.org/archives/html/xen-devel/2021-03/msg01178.html
I don't know what Xen's expected min QEMU version is, but if it
can assume QEMU >= 2.12, then there's no need to check for existance
of query-cpus-fast, and can just apply
diff --git a/tools/libs/light/libxl_domain.c b/tools/libs/light/libxl_domain.c
index 5d4ec90711..5fdcc182c0 100644
--- a/tools/libs/light/libxl_domain.c
+++ b/tools/libs/light/libxl_domain.c
@@ -1749,14 +1749,14 @@ static int qmp_parse_query_cpus(libxl__gc *gc,
const libxl__json_object *cpu;
libxl_bitmap_set_none(map);
- /* Parse response to QMP command "query-cpus":
- * [ { 'CPU': 'int',...} ]
+ /* Parse response to QMP command "query-cpus-fast":
+ * [ { 'cpu-index': 'int',...} ]
*/
for (i = 0; (cpu = libxl__json_array_get(response, i)); i++) {
unsigned int cpu_index;
const libxl__json_object *o;
- o = libxl__json_map_get("CPU", cpu, JSON_INTEGER);
+ o = libxl__json_map_get("cpu-index", cpu, JSON_INTEGER);
if (!o) {
LOGD(ERROR, domid, "Failed to retrieve CPU index.");
return ERROR_QEMU_API;
@@ -1841,7 +1841,7 @@ int libxl_set_vcpuonline(libxl_ctx *ctx, uint32_t domid,
LIBXL_QMP_CMD_TIMEOUT * 1000);
if (rc) goto out;
qmp->callback = set_vcpuonline_qmp_cpus_queried;
- rc = libxl__ev_qmp_send(egc, qmp, "query-cpus", NULL);
+ rc = libxl__ev_qmp_send(egc, qmp, "query-cpus-fast", NULL);
if (rc) goto out;
return AO_INPROGRESS;
default:
@@ -2199,7 +2199,7 @@ static void retrieve_domain_configuration_lock_acquired(
libxl_bitmap_alloc(CTX, &rdcs->qemuu_cpus,
d_config->b_info.max_vcpus);
rdcs->qmp.callback = retrieve_domain_configuration_cpu_queried;
- rc = libxl__ev_qmp_send(egc, &rdcs->qmp, "query-cpus", NULL);
+ rc = libxl__ev_qmp_send(egc, &rdcs->qmp, "query-cpus-fast", NULL);
if (rc) goto out;
has_callback = true;
}
If Xen needs to support QEMU < 2.12, then it will need to
probe for existance of query-cpus-fast using "query-commands"
as libvirt does...
> This suggests we should probably try to coordinate a bit better
> with Xen as one of our downstream QMP users.
They could be added to the MAINTAINERS file for the deprecated features
doc, so that paches automatically CC xen-devel (or another suitable
list or person).
> Am I right in thinking that QEMU now has an option that Xen
> could turn on in their CI for "make attempts to use deprecated
> features fail" so they could catch them earlier in the
> deprecate-and-delete cycle?
Yes, you just merged it from Markus:
https://lists.gnu.org/archive/html/qemu-devel/2021-03/msg06803.html
it won't capture all deprecations, but it will catch QMP related ones
and thus I believe would have caught the query-cpus deprecaton.
Regards,
Daniel
--
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