diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index e5b77d63769a06f16dc815c9fa995783a7d65d86..3871034818b119b340db22ccd7eb2a3eff7c1ffa 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -2195,6 +2195,7 @@ qemuProcessInitCpuAffinity(virDomainObjPtr vm)
     int ret = -1;
     virBitmapPtr cpumap = NULL;
     virBitmapPtr cpumapToSet = NULL;
+    virBitmapPtr hostcpumap = NULL;
     qemuDomainObjPrivatePtr priv = vm->privateData;
 
     if (!vm->pid) {
@@ -2217,20 +2218,34 @@ qemuProcessInitCpuAffinity(virDomainObjPtr vm)
              * its config file */
             int hostcpus;
 
-            /* setaffinity fails if you set bits for CPUs which
-             * aren't present, so we have to limit ourselves */
-            if ((hostcpus = virHostCPUGetCount()) < 0)
+            if (virHostCPUHasBitmap()) {
+                hostcpumap = virHostCPUGetOnlineBitmap();
+                cpumap = virProcessGetAffinity(vm->pid);
+            }
+
+            if (hostcpumap && cpumap && virBitmapEqual(hostcpumap, cpumap)) {
+                /* we're using all available CPUs, no reason to set
+                 * mask. If libvirtd is running without explicit
+                 * affinity, we can use hotplugged CPUs for this VM */
+                ret = 0;
                 goto cleanup;
+            } else {
+                /* setaffinity fails if you set bits for CPUs which
+                 * aren't present, so we have to limit ourselves */
+                if ((hostcpus = virHostCPUGetCount()) < 0)
+                    goto cleanup;
 
-            if (hostcpus > QEMUD_CPUMASK_LEN)
-                hostcpus = QEMUD_CPUMASK_LEN;
+                if (hostcpus > QEMUD_CPUMASK_LEN)
+                    hostcpus = QEMUD_CPUMASK_LEN;
 
-            if (!(cpumap = virBitmapNew(hostcpus)))
-                goto cleanup;
+                virBitmapFree(cpumap);
+                if (!(cpumap = virBitmapNew(hostcpus)))
+                    goto cleanup;
 
-            virBitmapSetAll(cpumap);
+                virBitmapSetAll(cpumap);
 
-            cpumapToSet = cpumap;
+                cpumapToSet = cpumap;
+            }
         }
     }
 
@@ -2241,6 +2256,7 @@ qemuProcessInitCpuAffinity(virDomainObjPtr vm)
 
  cleanup:
     virBitmapFree(cpumap);
+    virBitmapFree(hostcpumap);
     return ret;
 }