[RFC,0/1] target/riscv: Make property names lowercase and add capitalized aliases

Message

Tsukasa OI May 13, 2022, 9:46 a.m. UTC

Hello,

While I'm reviewing Dao Lu's Zihintpause patch, I noticed something.

c.f. <https://lists.gnu.org/archive/html/qemu-riscv/2022-05/msg00210.html>

While some CPU configuration properties have capitalized names but others
have lowercase names.  See riscv_cpu_properties in target/riscv/cpu.c
for example:

    DEFINE_PROP_BOOL("i", RISCVCPU, cfg.ext_i, true),
    DEFINE_PROP_BOOL("e", RISCVCPU, cfg.ext_e, false),
    DEFINE_PROP_BOOL("g", RISCVCPU, cfg.ext_g, true),

...

    DEFINE_PROP_BOOL("Counters", RISCVCPU, cfg.ext_counters, true),
    DEFINE_PROP_BOOL("Zifencei", RISCVCPU, cfg.ext_ifencei, true),
    DEFINE_PROP_BOOL("Zicsr", RISCVCPU, cfg.ext_icsr, true),

...

    DEFINE_PROP_BOOL("zba", RISCVCPU, cfg.ext_zba, true),
    DEFINE_PROP_BOOL("zbb", RISCVCPU, cfg.ext_zbb, true),
    DEFINE_PROP_BOOL("zbc", RISCVCPU, cfg.ext_zbc, true),

...

I think this is not good.  Property names should have some sort of
consistency (especially when those names are case sensitive).  This is
what happens when invalid property is specified:

Invalid: -cpu rv64,counters=off
Valid  : -cpu rv64,Counters=off

    qemu-system-riscv64: can't apply global rv64-riscv-cpu.counters=off: Property 'rv64-riscv-cpu.counters' not found

But we can't just remove such names for compatibility.

I found a way to make "property aliases" and that way, we can make both
"Counters" and "counters" valid.  I chose lowercase names (because of
number of properties implemented) as primary ones and capitalized names
are defined as aliases.

For instance, I'll show how both "counters" and "Counters" are implemented
below. They share three arguments but on alias (the second one),:

-   it uses DEFINE_PROP on alias to disable setting default value and
-   it defines property type (that is generally set by DEFINE_PROP_BOOL but
    must be set manually because the alias uses DEFINE_PROP).

    DEFINE_PROP_BOOL("counters", RISCVCPU, cfg.ext_counters, true),
    DEFINE_PROP     ("Counters", RISCVCPU, cfg.ext_counters, qdev_prop_bool, bool),




Tsukasa OI (1):
  target/riscv: Make property names lowercase

 target/riscv/cpu.c | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)


base-commit: 178bacb66d98d9ee7a702b9f2a4dfcd88b72a9ab