Re: [PATCH v1 RFC Zisslpcfi 3/9] target/riscv: implements CSRs and new bits in existing CSRs in zisslpcfi

[Richard Henderson]

On 2/15/23 13:33, Deepak Gupta wrote:
> On Tue, Feb 14, 2023 at 9:47 PM LIU Zhiwei <zhiwei_liu@linux.alibaba.com> wrote:
> > And MSTATUS_UBCFIEN field change don't need flush tlb.
>
> TCG code-gen would be different depending on whether ubcfi is enabled or not.
> As an example a TB might have code generated when bcfi was enabled.
> But if someone disables it,
> translation needs to happen again and zimops implementation should be
> generated this time.

tlb_flush does not affect translation.  TB are tied to physical addresses and are only 
flushed by writes or tb_flush().

The correct fix is to allocate a bit from FIELD(TB_FLAGS, X, Y, 1), and adjust 
cpu_get_tb_cpu_state to indicate when CFI is active in the current cpu mode.


r~