qemu_process: Issue an info message when subtracting isolcpus

In one of my previous commits I've made us substract isolcpus
from all online CPUs when setting affinity on QEMU threads. See
commit below for more info on that. Nevertheless, this is
something that surely deserves an entry in log. I've chosen INFO
priority for now. We can promote that to a regular WARN if users
complain.

Fixes: da95bcb6b2
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

src/qemu/qemu_process.c

@@ -2348,6 +2348,12 @@ qemuProcessGetAllCpuAffinity(virBitmap **cpumapRet)
         return -1;
 
     if (isolCpus) {
+        g_autofree char *isolCpusStr = virBitmapFormat(isolCpus);
+        g_autofree char *cpumapRetStr = virBitmapFormat(*cpumapRet);
+
+        VIR_INFO("Subtracting isolated CPUs %1$s from online CPUs %2$s",
+                 isolCpusStr, cpumapRetStr);
+
         virBitmapSubtract(*cpumapRet, isolCpus);
     }