[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] unhandled word causes Xen crash with recent Linux kernels, was: Re: [PATCH v2 05/11] xen/arm: vgic: Properly emulate the full register
On Mon, 2015-11-30 at 12:22 +0000, Julien Grall wrote: > Hi Ian, > > On 25/11/15 12:26, Ian Campbell wrote: > > On Wed, 2015-11-25 at 12:15 +0000, Stefano Stabellini wrote: > > > On Wed, 25 Nov 2015, Shannon Zhao wrote: > > > > Upstream Linux kernel applies below patch which will write > > > > GICD_ICACTIVER. But since Xen doesn't support it, so it will cause > > > > Dom0 > > > > initializes GIC failed. > > > > > > > > 0eece2b22849c90b730815c893425a36b9d10fd5 (irqchip/gic: Make sure > > > > all > > > > interrupts are deactivated at boot) > > > > > > > > (XEN) d0v0: vGICD: unhandled word write 0xffffffff to ICACTIVER4 > > > > (XEN) traps.c:2447:d0v0 HSR=0x93860046 pc=0xffffffc0008d63f0 > > > > gva=0xffffff8000004384 gpa=0x0000002f000384 > > > > (XEN) DOM0: Unhandled fault: ttbr address size fault (0x96000000) > > > > at > > > > 0xffffff8000004384 > > > > (XEN) DOM0: Internal error: : 96000000 [#1] PREEMPT SMP > > > > (XEN) DOM0: Modules linked in: > > > > (XEN) DOM0: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.0-rc2+ > > > > #364 > > > > (XEN) DOM0: Hardware name: (null) (DT) > > > > (XEN) DOM0: task: ffffffc000969970 ti: ffffffc00095c000 task.ti: > > > > ffffffc00095c000 > > > > (XEN) DOM0: PC is at gic_dist_config+0x78/0xa0 > > > > (XEN) DOM0: LR is at __gic_init_bases+0x240/0x2bc > > > > > > > > Do we have a plan to fix this? > > > > > > Thanks for the reporting the issue, I can reproduce the > > > problem.ÂÂGiven > > > that this is a very serious regression and that we cannot really > > > "fix" > > > the Linux side because Linux is not doing anything wrong, I think we > > > have to go with a very simple change, something we can easily > > > backport > > > to all past Xen releases. > > > > > > I suggest we turn the "unhandled word write" into a write_ignore, see > > > below: > > > > As discussed IRL this might be tolerable as a patch intended for > > backporting purposes, but I would want to see it in a series along with > > one > > or more not-for-backport patches which actually makes the register work > > as > > it should. > > I have the feeling that fixing properly GICD_I*ACTIVER will take > sometimes as we also need to take into consideration hardware interrupt > routed to a guest. > > As this is preventing Linux upstream to run on the latest, can we get a > simple fix for now? With a suitable commit message explaining the interim/backportability nature of this patch and the intention to do it properly I'd be willing to accept it. Ian. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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