[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] IOMMU: don't disable bus mastering on faults for devices used by Xen or Dom0
On Tue, 2012-11-06 at 10:19 +0000, Jan Beulich wrote: > > This check is really there to stop a mad device from hosing the system > > rather than to contain a malicious OS, and a properly out-of-control > > device needs to be stopped or it will livelock Xen with iommu faults. > > In a uniprocessor system, dom0 might never get the chance to fix it. > > If that's the main goal, then on the AMD side the code may not do > what you want it to: PPR log entries, causing interrupts too, don't > get limited/suppressed in any way, yet are obviously to some > extent under guest control. > IIRC, PPR are dealt with in softirq context too, aren't they? > But yes, for the purpose here limiting the fault rate in some way > (with a slightly higher limit for Dom0 than DomU-s) would indeed > be the better route. > BTW, yes, independently from the above and for what it counts, I agree with this. Regards, Dario -- <<This happens because I choose it to happen!>> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://retis.sssup.it/people/faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK) Attachment:
signature.asc _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |