Re: [PATCH] target/ppc: Fix e6500 boot

["Cédric Le Goater" <clg@kaod.org>]

On 12/13/21 14:35, Fabiano Rosas wrote:
> When Altivec support was added to the e6500 kernel in 2012[1], the
> QEMU code was not changed, so we don't register the VPU/VPUA
> exceptions for the e6500:
> 
>    qemu: fatal: Raised an exception without defined vector 73
> 
> Note that the error message says 73, instead of 32, which is the IVOR
> for VPU. This is because QEMU knows only knows about the VPU interrupt
> for the 7400s. In theory, we should not be raising _that_ VPU
> interrupt, but instead another one specific for the e6500.
> 
> We unfortunately cannot register e6500-specific VPU/VPUA interrupts
> because the SPEU/EFPDI interrupts also use IVOR32/33. These are
> present only in the e500v1/2 versions. From the user manual:
> 
> e500v1, e500v2: only SPEU/EFPDI/EFPRI
> e500mc, e5500:  no SPEU/EFPDI/EFPRI/VPU/VPUA
> e6500:          only VPU/VPUA
> 
> So I'm leaving IVOR32/33 as SPEU/EFPDI, but altering the dispatch code
> to convert the VPU #73 to a #32 when we're in the e6500. Since the
> handling for SPEU and VPU is the same this is the only change that's
> needed. The EFPDI is not implemented and will cause an abort. I don't
> think it worth it changing the error message to take VPUA into
> consideration, so I'm not changing anything there.
> 
> This bug was discussed in the thread:
> https://lists.gnu.org/archive/html/qemu-ppc/2021-06/msg00222.html
> 
> 1- https://git.kernel.org/torvalds/c/cd66cc2ee52
> 
> Reported-by: <mario@locati.it>
> Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Applied to ppc-next.

Thanks,

C.