Re-test this issue on kvm-83-164.el5_5.7 with the steps in bug #583947.
Guest does not aborted after stop nfs server, it paused and output following messages:

(qemu) info status 
VM status: running
(qemu) bdrv_write ret=-5
qcow2: free_clusters failed: Input/output error
VM is stopped due to disk write error: ide0-hd1: Input/output error

(qemu) 
(qemu) info status 
VM status: paused
(qemu) 

*Then start nfs server, and after 5 sec input "cont" in qemu monitor*


(qemu) c
(qemu)
(qemu) info status 
VM status: running

*stop nfs server again*

(qemu)ide_dma_cancel: aiocb still pendingide_dma_cancel: BM_STATUS_DMAING still pendingbdrv_write ret=-5
qcow2: free_clusters failed: Input/output error
VM is stopped due to disk write error: ide0-hd1: Input/output error

(qemu) 

So, this bug is fixed and verified PASS.

An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHBA-2010-0419.html