[Xen-changelog] [xen-4.1-testing] x86/hvm: Crash domain rather than guest on unexpected PIO IO state

[Xen patchbot-4.1-testing <patchbot@xxxxxxx>]

# HG changeset patch
# User George Dunlap <george.dunlap@xxxxxxxxxxxxx>
# Date 1308167120 -3600
# Node ID 1980763433607fb28e5857850954b3d05e71d899
# Parent  d105e0a98b586583b17648026037a016bcf70912
x86/hvm: Crash domain rather than guest on unexpected PIO IO state

Under certain conditions, if an IO gets into an unexpected state,
hvmemul_do_io can return X86EMUL_UNHANDLEABLE.  Unfortunately,
handle_pio() does not expect this state, and calls BUG() if it sees
it, crashing the host.

Other HVM io-related code crashes the guest in this case.  This patch
makes handle_pio() do the same.

The crash was seen when executing crash_guest in dom0 to forcibly
crash the guest.

Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
xen-unstable changeset:   23538:35b4220c98bc
xen-unstable date:        Wed Jun 15 16:05:14 2011 +0100
---


diff -r d105e0a98b58 -r 198076343360 xen/arch/x86/hvm/io.c
--- a/xen/arch/x86/hvm/io.c     Wed Jun 15 20:44:44 2011 +0100
+++ b/xen/arch/x86/hvm/io.c     Wed Jun 15 20:45:20 2011 +0100
@@ -239,7 +239,9 @@
         curr->arch.hvm_vcpu.io_state = HVMIO_handle_pio_awaiting_completion;
         break;
     default:
-        BUG();
+        gdprintk(XENLOG_ERR, "Weird HVM ioemulation status %d.\n", rc);
+        domain_crash(curr->domain);
+        break;
     }
 
     return 1;

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