At 17:14 +0000 on 15 Mar (1331831693), Stefano Stabellini wrote: > On Thu, 15 Mar 2012, Julien Grall wrote: > > When an IOREQ_TYPE_INVALIDATE is sent to QEMU, it invalidates all entry > > of the map cache even if it's locked. > > > > QEMU is not able to know that entry was invalidated, so when an IO > > access is requested a segfault occured. > > The problem here is the long term mappings in QEMU that cannot easily be > re-created. > I am not sure whether this can cause any trouble to things like > xenpaging.
It causes some trouble to ballooning - a guest might try to return memory to Xen only to find that Qemu won't let go of it. If (as I hope is the case) qemu never has a locked mapping to something that the guets ought to be ballooning, that's OK. If this happens just because the page was recently a DMA target, then it's not. Cheers, Tim.
