Re: [Xen-devel] Cs/ 14346 breaks 64bit hv

[Tim Deegan <Tim.Deegan@xxxxxxxxxxxxx>]

At 01:47 -0500 on 14 Mar (1173836821), Woller, Thomas wrote:
> Took a look at the rombios.s code generated in both cases (14344 and
> 14345) and seems like the "jump to the boot vector" code is not executed
> on the failing case.  There is a "default: return" in the function
> immediately above an "#if BX_TCGBIOS", and then the non-executed asm
> code. 
> Is bcc not understanding that the asm code following should be executed?
> Seems like there is added a default "return" so that the "jump to boot
> vector" code is never executed?  appears to be the case..but not sure.  

That would be terrifying.  Presumably there's a jmp past that ret
somewhere.  I got the impression from your first email that some
guests do boot, and that can only happen through that iret. 

Does adding an explicit "return;" in C after the asm block change the
behaviour?

> Code snippets are below.  Using gcc 3.3.5, but will try 4.x compiler,
> although looks like bcc is used to generate the rombios.s file if I read
> the Makefile correctly.

Yep.  What version of bcc are you using? (bcc -v says 0.16.14 for me)

Cheers,

Tim.

-- 
Tim Deegan <Tim.Deegan@xxxxxxxxxxxxx>, XenSource UK Limited
Registered office c/o EC2Y 5EB, UK; company number 05334508

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