Re: [PATCH v3 02/13] tcg/s390x: Remove TCG_REG_TB

[Richard Henderson]

On 12/7/22 01:45, Thomas Huth wrote:
> On 06/12/2022 23.22, Richard Henderson wrote:
> > On 12/6/22 13:29, Ilya Leoshkevich wrote:
> > > This change doesn't seem to affect that, but what is the minimum
> > > supported s390x qemu host? z900?
> >
> > Possibly z990, if I'm reading the gcc processor_flags_table[] correctly; 
> > long-displacement-facility is definitely a minimum.
> >
> > We probably should revisit what the minimum for TCG should be, assert those features at 
> > startup, and drop the corresponding runtime tests.
>
> If we consider the official IBM support statement:
>
> https://www.ibm.com/support/pages/system/files/inline-files/IBM%20Mainframe%20Life%20Cycle%20History%20V2.10%20-%20Sept%2013%202022_1.pdf
>
> ... that would mean that the z10 and all older machines are not supported 
> anymore.

Thanks for the pointer.  It would appear that z114 exits support at the end of this month, 
which would leave z12 as minimum supported cpu.

Even assuming z196 gets us extended-immediate, general-insn-extension, load-on-condition, 
and distinct-operands, which are all quite important to TCG, and constitute almost all of 
the current runtime checks.

The other metric would be matching the set of supported cpus from the set of supported os 
distributions, but I would be ready to believe z196 is below the minimum there too.


r~