Re: [PATCH v3 3/6] target/riscv: add remaining named features

[Andrew Jones]

On Fri, Feb 02, 2024 at 12:21:51PM -0300, Daniel Henrique Barboza wrote:
> The RVA22U64 and RVA22S64 profiles mandates certain extensions that,
> until now, we were implying that they were available.
> 
> We can't do this anymore since named features also has a riscv,isa
> entry. Let's add them to riscv_cpu_named_features[].
> 
> Instead of adding one bool for each named feature that we'll always
> implement, i.e. can't be turned off, add a 'ext_always_enabled' bool in
> cpu->cfg. This bool will be set to 'true' in TCG accel init, and all
> named features will point to it. This also means that KVM won't see
> these features as always enable, which is our intention.
> 
> If any accelerator adds support to disable one of these features, we'll
> have to promote them to regular extensions and allow users to disable it
> via command line.
> 
> After this patch, here's the riscv,isa from a buildroot using the
> 'rva22s64' CPU:
> 
>  # cat /proc/device-tree/cpus/cpu@0/riscv,isa
> rv64imafdc_zic64b_zicbom_zicbop_zicboz_ziccamoa_ziccif_zicclsm_ziccrse_
> zicntr_zicsr_zifencei_zihintpause_zihpm_za64rs_zfhmin_zca_zcd_zba_zbb_
> zbs_zkt_ssccptr_sscounterenw_sstvala_sstvecd_svade_svinval_svpbmt#
> 
> Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
> ---
>  target/riscv/cpu.c         | 42 +++++++++++++++++++++++++++++++-------
>  target/riscv/cpu_cfg.h     |  6 ++++++
>  target/riscv/tcg/tcg-cpu.c |  2 ++
>  3 files changed, 43 insertions(+), 7 deletions(-)
>

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>