Hi All, We did some testing for Xen-unstable tree with upstream QEMU. We covered basic guest booting up, power management, VT-d, SR-IOV features. We found 4 new bugs which only exist in upstream QEMU not in qemu-xen. We followed the below wiki page to use upstream QEMU. http://wiki.xen.org/wiki/QEMU_Upstream test tree: xen-unstable-tree.hg: C/S 26193 (about 20 days ago) qemu.git: commit e9bff10f8db (about 20 days ago) Dom0: Linux 3.6.9 release version. test machine: Intel Westmere-EP and SandyBridge-EP systems. new bugs (which don''t exist with qemu-xen-unstable tree): 1. ''maxvcpus=NUM'' item is not supported in upstream QEMU http://bugzilla.xen.org/bugzilla/show_bug.cgi?id=1837 -- This blocked vCPU hot-plug for HVM guest. 2. Guest console hangs after save/restore or live-migration when setting ''hpet=0'' in guest config file http://bugzilla.xen.org/bugzilla/show_bug.cgi?id=1837 3. ''xen_platform_pci=0'' setting cannot make the guest use emulated PCI devices by default http://bugzilla.xen.org/bugzilla/show_bug.cgi?id=1839 4. Guest free memory with upstream qemu is 14MB lower than that with qemu-xen-unstable.git http://bugzilla.xen.org/bugzilla/show_bug.cgi?id=1836 -- This might not be a bug; we just curious to know what the additional 14MB memory is for. Best Regards, Yongjie (Jay)