Re: [Xen-devel] Emulating in response of an int3 vm_event

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 02.12.15 at 19:34, <andrew.cooper3@xxxxxxxxxx> wrote:
> On 02/12/15 18:21, Tamas K Lengyel wrote:
>> Why would that vmread fail there and why would the call trace tell me
>> it's in vmx_vmenter_helper?
> 
> The symbol information is incorrect because of the bugframe being inside
> an UNLIKELY() block.
> 
> I have a patch to fix it,
> http://www.gossamer-threads.com/lists/xen/devel/404482?do=post_view_threaded 
> but this has been rejected.
> 
> I don't see a way to make a global symbol for the current translation
> units' unlikely section.  I also don't believe it is a sensible approach
> to take even if is a technical way to make it happen, as it still leaves
> the stack trace not correctly identifying the source of the issue, so
> the fix is in limbo.

I still don't see how that patch would help: You'd have a series of
machine generated unlikely.vmread.<n> labels in them, which
would still require you to look things up in disassembly. No different
to what I'm suggesting, only causing symbol table bloat.

Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel