[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH v2] exec: flush the whole TLB if a watchpoint crosses a page
From: |
Richard Henderson |
Subject: |
Re: [PATCH v2] exec: flush the whole TLB if a watchpoint crosses a page boundary |
Date: |
Wed, 3 Jun 2020 09:12:09 -0700 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 |
On 6/3/20 4:24 AM, Alex Bennée wrote:
> There is no particular reason why you can't have a watchpoint in TCG
> that covers a large chunk of the address space. We could be clever
> about it but these cases are pretty rare and we can assume the user
> will expect a little performance degradation.
>
> NB: In my testing gdb will silently squash a watchpoint like:
>
> watch (char[0x7fffffffff]) *0x0
>
> to a 4 byte watchpoint. Practically it will limit the maximum size
> based on max-value-size. However given enough of a tweak the sky is
> the limit.
>
> Reported-by: Alexander Bulekov <alxndr@bu.edu>
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
>
> ---
> v2
> - use cleaner in_page = -(addr | TARGET_PAGE_MASK) logic per rth
> ---
> exec.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Queued to tcg-next.
r~