George Dunlap
2011-Jun-14 13:54 UTC
[Xen-devel] [PATCH] xen: 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@eu.citrix.com>
diff -r 782bc7b2661a -r f93006ca6d02 xen/arch/x86/hvm/io.c
--- a/xen/arch/x86/hvm/io.c Fri Jun 10 13:51:39 2011 +0100
+++ b/xen/arch/x86/hvm/io.c Tue Jun 14 14:53:27 2011 +0100
@@ -239,7 +239,9 @@ int handle_pio(uint16_t port, int size,
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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George Dunlap
2011-Jun-14 13:56 UTC
[Xen-devel] Re: [PATCH] xen: Crash domain rather than guest on unexpected PIO IO state
This is probably a candidate to backport to 4.1.x at some point. -George On Tue, 2011-06-14 at 14:54 +0100, George Dunlap wrote:> 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@eu.citrix.com> > > diff -r 782bc7b2661a -r f93006ca6d02 xen/arch/x86/hvm/io.c > --- a/xen/arch/x86/hvm/io.c Fri Jun 10 13:51:39 2011 +0100 > +++ b/xen/arch/x86/hvm/io.c Tue Jun 14 14:53:27 2011 +0100 > @@ -239,7 +239,9 @@ int handle_pio(uint16_t port, int size, > 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;_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel