Re: [PATCH 0/2] Update use_goto_tb() in hppa and rx targets

[Alex Bennée]

Richard Henderson <address@hidden> writes:

> On 5/19/20 9:21 AM, Ahmed Karaman wrote:
>> The issue arose because the page crossings check in use_goto_tb()
>> function is required only in the system mode. Checking it in both modes
>> causes an unnecessary overhead in the user mode.
>
> It is not only required in system mode.
>
> You can see failures in user-mode if you modify executable pages, or change
> their permissions with mmap.  Such as if the guest program contains a
> JIT.

If we kept better track couldn't we just tb_flush() if a new +x region
gets mmaped? I guess that would be sub-optimal compared to having a
translation cache per mmap region.

-- 
Alex Bennée