From 18c9d1578bae7576c0c34c10c9a8ec9e4061d3b2 Mon Sep 17 00:00:00 2001 From: Peter Krempa Date: Fri, 26 Jun 2015 13:58:20 +0200 Subject: [PATCH] qemu: agent: Don't automatically disable CPU0 via guest agent 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 043695b3ac..7021a7a78b 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",