Re: [PATCH v2 1/3] trans_rvv.c.inc: write CSRs must call mark_vs_dirty() too

[Richard Henderson]

On 2/16/24 03:57, Daniel Henrique Barboza wrote:
> In the Vector spec section 3.2 [1]:
>
> "When mstatus.VS is set to Initial or Clean, executing any instruction
>   that changes vector state, including the vector CSRs, will change
>   mstatus.VS to Dirty."
>
> ldst_us_trans(), ldst_stride_trans(), ldst_index_trans() and
> ldst_whole_trans() will change vector state regardless of being a store
> op or not. Stores will set env->vstart to zero after execution (see
> vext_ldst_us() in vector_helper.c), and this is vector CSR state change.

In Initial or Clean state, it could be argued that vstart is already zero, so is there 
really a change to state?

OTOH, on the exception path out of a vector store, where we *do* set vstart != 0, we do 
not also set vs dirty.

Therefore I think that loads and stores need to manage dirty within the helper, alongside 
the management of vstart, or perhaps move the mark_vs_dirty call to *before* the call to 
the helper.


r~