On Sun, Apr 27, 2014 at 09:34:06AM +0100, Peter Maydell wrote: > On 27 April 2014 09:29, Michael S. Tsirkin <m...@redhat.com> wrote: > > On Tue, Apr 22, 2014 at 04:55:15PM +0800, Fam Zheng wrote: > >> If guest driver behaves abnormally, emulation code could mark the device > >> as "broken". > >> > >> Once "broken" is set, device emulation will typically wait for a reset > >> command and ignore any other operations, but it could also return error > >> responds. In other words, whether and how does guest know about this > >> error status is device specific. > >> > >> Signed-off-by: Fam Zheng <f...@redhat.com> > > > > I'm assuming the idea is to make debugging guest drivers easier > > for people not familiar with qemu? > > As a general rule, guests shouldn't be able to cause QEMU to > just randomly exit. We have a bunch of code in tree which does > handle guest errors this way, of course, but cleanups to fix it > are worth having.
OK so by using a wrong address an MMIO handler can e.g. start MMIO on the device itself instead of doing DMA, this will cause an infinite loop. Any idea how to fix this? > The benefits include that one duff device > driver doesn't take out your whole VM, that you have a chance > for a clean shutdown, and reboot might restore the operation of > the offending device. > > There was a thread about this a little while back. > > thanks > -- PMM I agree, but I'd like the change to be done in a way that does not make debugging harder. -- MST