Re: [Xen-devel] xen-unstabel + linux 4.2: MMIO emulation failed: d23v0 64bit @ 0010:ffffffff814e2b1c -> 66 89 02 48 8d 55 c0 48 89 5d c0 44 89 65 c8 e8

[linux@xxxxxxxxxxxxxx]

On 2015-07-27 16:07, Andrew Cooper wrote:
> On 24/07/15 19:56, linux@xxxxxxxxxxxxxx wrote:
> > Hi All,
> >
> > On my AMD system running xen-unstable (last commit: ),
> >  after a few restarts of a HVM guest with pci-passthrough i got these
> > on shutdown of the guest:
> > (never seen this before, so it should be something triggered by a
> > recent commit)
> >
> > --
> > Sander
> >
> >
> > .... (probably lost before but that's lost)
> >
> > (XEN) [2015-07-24 18:46:53.732] domain_crash called from io.c:166
> > (XEN) [2015-07-24 18:46:53.732] io.c:165:d23v0 Weird HVM ioemulation
> > status 1.
> > (XEN) [2015-07-24 18:46:53.732] domain_crash called from io.c:166
> > (XEN) [2015-07-24 18:46:53.732] io.c:165:d23v0 Weird HVM ioemulation
> > status 1.
> > (XEN) [2015-07-24 18:46:53.732] domain_crash called from io.c:166
> > (XEN) [2015-07-24 18:46:53.732] io.c:165:d23v0 Weird HVM ioemulation
> > status 1.
> Paul: this is very likely an issue your emulation series.
>
> 66 89 02 is mov %ax,(%rdx), but has ended up in handle_pio() which 
> seems
> wrong.
>
> Sander: Please can you rerun with the following debug
>
> diff --git a/xen/arch/x86/hvm/io.c b/xen/arch/x86/hvm/io.c
> index d3b9cae..7560d08 100644
> --- a/xen/arch/x86/hvm/io.c
> +++ b/xen/arch/x86/hvm/io.c
> @@ -163,7 +163,9 @@ int handle_pio(uint16_t port, unsigned int size, 
> int
> dir)
>          break;
>      default:
>          gdprintk(XENLOG_ERR, "Weird HVM ioemulation status %d.\n", 
> rc);
> -        domain_crash(curr->domain);
> +        show_execution_state(curr);
> +        dump_execution_state();
> +        domain_crash_synchronous(curr->domain);
>          break;
>      }
>
> ~Andrew

Hi Andrew,

I tried your debug patch, however that doesn't print anything new to xl 
dmesg.
It seems to be too busy trying to crash .. (although that actually seems 
to fail)
This was testing on a tree with a619657e2d5725a61cb72f65901db42e98f2a896 
as last commit and it fails at the first shutdown of the guest.
After that i tried it with the current staging tree with 
44313ab77f3e3c5b566ea4f23b0e32bfd5eafa29 as last commit
and i don't to get those failures anymore .. i even done a start 
shutdown loop of 100 iterations .. everything was fine.
--
Sander

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