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

[Andrew Cooper <andrew.cooper3@citrix.com>]

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

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