Re: [kvm-unit-tests PATCH 3/3] s390x: pv: Add IPL reset tests

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

On Tue, 21 Feb 2023 10:26:11 +0100
Janosch Frank <frankja@linux.ibm.com> wrote:

[...]

> 
> >> +/* Execute the diag500 which will set the subcode we execute in gr2 */
> >> +diag	0, 0, 0x500
> >> +
> >> +/*
> >> + * A valid PGM new PSW can be a real problem since we never fall out
> >> + * of SIE and therefore effectively loop forever. 0 is a valid PSW
> >> + * therefore we re-use the reset_psw as this has the short PSW
> >> + * bit set which is invalid for a long PSW like the exception new
> >> + * PSWs.
> >> + *
> >> + * For subcode 0/1 there are no PGMs to consider.
> >> + */
> >> +lgrl   %r5, reset_psw
> >> +stg    %r5, GEN_LC_PGM_NEW_PSW
> >> +
> >> +/* Clean registers that are used */
> >> +xgr	%r0, %r0
> >> +xgr	%r1, %r1
> >> +xgr	%r3, %r3
> >> +xgr	%r4, %r4
> >> +xgr	%r5, %r5
> >> +xgr	%r6, %r6
> >> +
> >> +/* Subcode 0 - Modified Clear */  
> > 
> > what about subcode 1?  
> 
> My guess is that this hasn't been removed after a re-work of the code.
> I suggest to remove the comment.

sounds good

> 
> >   
> >> +SET_RESET_PSW_ADDR done
> >> +diag	%r0, %r2, 0x308
> >> +
> >> +/* Should never be executed because of the reset PSW */
> >> +diag	0, 0, 0x44
> >> +
> >> +done:
> >> +lghi	%r1, 42
> >> +diag	%r1, 0, 0x9c
> >> +
> >> +
> >> +	.align	8
> >> +reset_psw:
> >> +	.quad	0x0008000180000000  
> >   
>