Subject: [RFC v2 0/5] arm64: kvm: reset hyp context for kexec

From: [email-masked] (Marc Zyngier)
Date: Mon, 30 Mar 2015 08:16:13 +0100

On Mon, 30 Mar 2015 02:39:53 +0100
AKASHI Takahiro <[email-masked]> wrote:

> On 03/28/2015 02:40 AM, Kyle McMartin wrote:
> > On Fri, Mar 27, 2015 at 03:37:04PM +0000, Marc Zyngier wrote:
> >>> [  236.260863] Kernel panic - not syncing: HYP panic:
> >>> [  236.260863] PS:600003c9 PC:000003ffffff0830 ESR:0000000096000006
> >>
> >> It would be interesting if you could find out what you have at offset
> >> 0x830 of hyp-init.o (the stack trace is for EL1, and is not going to
> >> help much).
> >>
> >
> > Given the alignment, i'm going to assume i'm looking at the right thing:
> >
> > 0000000000000820 <__kvm_hyp_reset>:
> >       820:       d51c2000        msr     ttbr0_el2, x0
> >       824:       d5033fdf        isb
> >       828:       d50c871f        tlbi    alle2
> >       82c:       d5033f9f        dsb     sy
> >       830:       10000060        adr     x0, 83c <__kvm_hyp_reset+0x1c>
> >       834:       b3403c01        bfxil   x1, x0, #0, #16
> >       838:       d61f0020        br      x1
> >       83c:       d53c1000        mrs     x0, sctlr_el2
> >
> > but it seems fairly implausible to be trapping on ADR x0, 1f...
> 
> 
> I've never seen this panic on fast model...
> 
> ESR shows that
>    - Exception class: Data abort taken without a change in Exception level
>    - Data fault status code: Translation fault at EL2
> 
> and FAR seems not to be a proper address.

... which is consistent with what we're seeing here (data fault on
something that doesn't generate a load/store). I'm pretty sure the
page tables are screwed.

Have you tested it with 64k pages?

Thanks,

        M.
-- 
Jazz is not dead. It just smells funny.