On Wed, Jul 19, 2023 at 09:06:08AM +0100, Andrew Cooper wrote:
> On 19/07/2023 8:38 am, Jan Beulich wrote:
> > Loading the VGA base address involves sym_esi(), i.e. %esi still needs
> > to hold the relocation base address. Therefore the address of the
> > message to output cannot be "passed" in %esi. Put the message offset in
> > %ecx instead, adding it into %esi _after_ its last use as base address.
> >
> > Fixes: b28044226e1c ("x86: make Xen early boot code relocatable")
> > Signed-off-by: Jan Beulich <[email protected]>
>
> When I was doing the label cleanup, I did wonder how this worked, given
> that it clobbered %esi. I guess this is the answer...
>
> Acked-by: Andrew Cooper <[email protected]>
>
> Although it occurs to me that probably want to (optionally) use one of
> the IO-port/Hypercall protocols too to get these messages in PVH boot
> case too.
Using XEN_HVM_DEBUGCONS_IOPORT would be my preference, as it's the
same IO port that's used by QEMU as a debug console.
Roger.
