[PATCH] qga: Correct loop count in qmp_guest_get_vcpus()

* [PATCH] qga: Correct loop count in qmp_guest_get_vcpus()
@ 2020-11-19  6:08 Lin Ma
  2020-11-19  6:12 ` no-reply
  0 siblings, 1 reply; 6+ messages in thread
From: Lin Ma @ 2020-11-19  6:08 UTC (permalink / raw)
  To: qemu-devel; +Cc: mdroth, Lin Ma

The guest-get-vcpus returns incorrect vcpu info in case we hotunplug vcpus(not
the last one).
e.g.:
A VM has 4 VCPUs: cpu0 + 3 hotunpluggable online vcpus(cpu1, cpu2 and cpu3).
Hotunplug cpu2,  Now only cpu0, cpu1 and cpu3 are present & online.

./qmp-shell /tmp/qmp-monitor.sock
(QEMU) query-hotpluggable-cpus
{"return": [
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 3}, "vcpus-count": 1,
 "qom-path": "/machine/peripheral/cpu3", "type": "host-x86_64-cpu"},
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 2}, "vcpus-count": 1,
 "qom-path": "/machine/peripheral/cpu2", "type": "host-x86_64-cpu"},
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 1}, "vcpus-count": 1,
 "qom-path": "/machine/peripheral/cpu1", "type": "host-x86_64-cpu"},
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 0}, "vcpus-count": 1,
 "qom-path": "/machine/unattached/device[0]", "type": "host-x86_64-cpu"}
]}

(QEMU) device_del id=cpu2
{"return": {}}

(QEMU) query-hotpluggable-cpus
{"return": [
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 3}, "vcpus-count": 1,
 "qom-path": "/machine/peripheral/cpu3", "type": "host-x86_64-cpu"},
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 2}, "vcpus-count": 1,
 "type": "host-x86_64-cpu"},
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 1}, "vcpus-count": 1,
 "qom-path": "/machine/peripheral/cpu1", "type": "host-x86_64-cpu"},
{"props": {"core-id": 0, "thread-id": 0, "socket-id": 0}, "vcpus-count": 1,
 "qom-path": "/machine/unattached/device[0]", "type": "host-x86_64-cpu"}
]}

Before:
./qmp-shell -N /tmp/qmp-ga.sock
Welcome to the QMP low-level shell!
Connected
(QEMU) guest-get-vcpus
{"return": [
{"online": true, "can-offline": false, "logical-id": 0},
{"online": true, "can-offline": true, "logical-id": 1}]}

After:
./qmp-shell -N /tmp/qmp-ga.sock
Welcome to the QMP low-level shell!
Connected
(QEMU) guest-get-vcpus
{"execute":"guest-get-vcpus"}
{"return": [
{"online": true, "can-offline": false, "logical-id": 0},
{"online": true, "can-offline": true, "logical-id": 1},
{"online": true, "can-offline": true, "logical-id": 3}]}

Signed-off-by: Lin Ma <lma@suse.com>
---
 qga/commands-posix.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index c089e38120..6452e14a0f 100644
--- a/qga/commands-posix.c
+++ b/qga/commands-posix.c
@@ -2466,15 +2466,15 @@ GuestLogicalProcessorList *qmp_guest_get_vcpus(Error **errp)
 {
     int64_t current;
     GuestLogicalProcessorList *head, **link;
-    long sc_max;
+    long max_loop_count;
     Error *local_err = NULL;
 
     current = 0;
     head = NULL;
     link = &head;
-    sc_max = SYSCONF_EXACT(_SC_NPROCESSORS_CONF, &local_err);
+    max_loop_count = SYSCONF_EXACT(_SC_NPROCESSORS_CONF, &local_err);
 
-    while (local_err == NULL && current < sc_max) {
+    while (local_err == NULL && current < max_loop_count) {
         GuestLogicalProcessor *vcpu;
         GuestLogicalProcessorList *entry;
         int64_t id = current++;
@@ -2491,6 +2491,8 @@ GuestLogicalProcessorList *qmp_guest_get_vcpus(Error **errp)
             *link = entry;
             link = &entry->next;
         }
+        else
+            max_loop_count += 1;
         g_free(path);
     }
 
-- 
2.29.1



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