While CPU0 was made unpluggable in Linux a while ago it's not desirable
to unplug it since some parts of the kernel (suspend-to-ram) still
depend on it.
This patch fixes the vCPU selection code in libvirt so that it will not
be disabled.
---
src/qemu/qemu_agent.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/src/qemu/qemu_agent.c b/src/qemu/qemu_agent.c
index 043695b..7021a7a 100644
--- a/src/qemu/qemu_agent.c
+++ b/src/qemu/qemu_agent.c
@@ -1601,9 +1601,13 @@ qemuAgentUpdateCPUInfo(unsigned int nvcpus,
size_t i;
int nonline = 0;
int nofflinable = 0;
+ ssize_t cpu0 = -1;
/* count the active and offlinable cpus */
for (i = 0; i < ncpuinfo; i++) {
+ if (cpuinfo[i].id == 0)
+ cpu0 = i;
+
if (cpuinfo[i].online)
nonline++;
@@ -1618,6 +1622,15 @@ qemuAgentUpdateCPUInfo(unsigned int nvcpus,
}
}
+ /* CPU0 was made offlinable in linux a while ago, but certain parts (suspend
+ * to ram) of the kernel still don't cope well with that. Make sure that if
+ * all remaining vCPUs are offlinable, vCPU0 will not be selected to be
+ * offlined automatically */
+ if (nofflinable == nonline && cpu0 >= 0 && cpuinfo[cpu0].online) {
+ cpuinfo[cpu0].offlinable = false;
+ nofflinable--;
+ }
+
/* the guest agent reported less cpus than requested */
if (nvcpus > ncpuinfo) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
--
2.4.1
