Re: 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

From: Sander Eikelenboom <linux@eikelenboom.it>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Paul Durrant <Paul.Durrant@citrix.com>, xen-devel@lists.xen.org
Subject: Re: 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
Date: Mon, 27 Jul 2015 16:44:30 +0200	[thread overview]
Message-ID: <1119624571.20150727164430@eikelenboom.it> (raw)
In-Reply-To: <55B63B2B.8070508@citrix.com>

Monday, July 27, 2015, 4:07:39 PM, you wrote:

> On 24/07/15 19:56, linux@eikelenboom.it 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

Well i have only seen this once now .. hasn't happened again so far, so 
it's not very reproduceable i'm afraid.

I can see when i can make some time to run a script that does a loop
on creating and shutting down a guest with pci-passthrough, see if i can
get it to fail again.

--
Sander

> 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