Re: [PATCH v4 1/6] trans_rvv.c.inc: mark_vs_dirty() before loads and stores

[Richard Henderson]

On 2/20/24 12:25, Daniel Henrique Barboza wrote:
> While discussing a problem with how we're (not) setting vstart_eq_zero
> Richard had the following to say w.r.t the conditional mark_vs_dirty()
> calls on load/store functions [1]:
>
> "I think it's required to have stores set dirty unconditionally, before
> the operation.
>
> Consider a store that traps on the 2nd element, leaving vstart = 2, and
> exiting to the main loop via exception. The exception enters the kernel
> page fault handler. The kernel may need to fault in the page for the
> process, and in the meantime task switch.
>
> If vs dirty is not already set, the kernel won't know to save vector
> state on task switch."
>
> Do a mark_vs_dirty() before both loads and stores.
>
> [1]72c7503b-0f43-44b8-aa82-fbafed2aac0c@linaro.org/">https://lore.kernel.org/qemu-riscv/72c7503b-0f43-44b8-aa82-fbafed2aac0c@linaro.org/
>
> Suggested-by: Richard Henderson<richard.henderson@linaro.org>
> Signed-off-by: Daniel Henrique Barboza<dbarboza@ventanamicro.com>
> ---
>   target/riscv/insn_trans/trans_rvv.c.inc | 23 ++++++++---------------
>   1 file changed, 8 insertions(+), 15 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~