Re: [PATCH 2/2] linux-user: Adjust guest page protection for the host

[Laurent Vivier]

Le 19/05/2020 à 20:56, Richard Henderson a écrit :
> Executable guest pages are never directly executed by
> the host, but do need to be readable for translation.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  linux-user/mmap.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/linux-user/mmap.c b/linux-user/mmap.c
> index 36fd1e2250..84662c3311 100644
> --- a/linux-user/mmap.c
> +++ b/linux-user/mmap.c
> @@ -76,8 +76,12 @@ static int validate_prot_to_pageflags(int *host_prot, int 
> prot)
>       * don't bother transforming guest bit to host bit.  Any other
>       * target-specific prot bits will not be understood by the host
>       * and will need to be encoded into page_flags for qemu emulation.
> +     *
> +     * Pages that are executable by the guest will never be executed
> +     * by the host, but the host will need to be able to read them.
>       */
> -    *host_prot = prot & (PROT_READ | PROT_WRITE | PROT_EXEC);
> +    *host_prot = (prot & (PROT_READ | PROT_WRITE))
> +               | (prot & PROT_EXEC ? PROT_READ : 0);
>  
>      return prot & ~valid ? 0 : page_flags;
>  }
> 

Applied to my linux-user-for-5.2 branch.

Thanks,
Laurent