Re: [PATCH for-8.2 0/2] target/riscv: add zicntr and zihpm flags

[Conor Dooley]

Hey,

On Mon, Jul 17, 2023 at 06:54:17PM -0300, Daniel Henrique Barboza wrote:
> Hi,
> 
> I decided to include flags for both timer/counter extensions to make it
> easier for us later on when dealing with the RVA22 profile (which
> includes both). 
> 
> The features were already implemented by Atish Patra some time ago, but
> back then these 2 extensions weren't introduced yet. This means that,
> aside from extra stuff in riscv,isa FDT no other functional changes were
> made.
> 
> Both are defaulted to 'true' since QEMU already implements both
> features, but the flag can be disabled if Zicsr isn't present or, in
> the case of zihpm, if pmu_num = 0.

Out of curiosity, since you are allowing them to be disabled, how do you
intend to communicate to a guest that zicsr or zihpm are not present?

> This means that,
> aside from extra stuff in riscv,isa FDT no other functional changes were
> made.

This is barely a "functional" change either, as the presence of these
extensions has to be assumed, whether they appear in riscv,isa or not :/

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