Re: [Qemu-devel] [PATCH for-3.1] target/arm: Remove workaround for small SAU regions

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 6/11/18 17:38, Peter Maydell wrote:
> Before we supported direct execution from MMIO regions, we
> implemented workarounds in commit 720424359917887c926a33d2
> which let us avoid doing so, even if the SAU or MPU region
> was less than page-sized.
> 
> Once we implemented execute-from-MMIO, we removed part
> of those workarounds in commit d4b6275df320cee76; but
> we forgot the one in get_phys_addr_pmsav8() which
> suppressed use of small SAU regions in executable regions.
> Remove that workaround now.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> ---
>   target/arm/helper.c | 12 ------------
>   1 file changed, 12 deletions(-)
> 
> diff --git a/target/arm/helper.c b/target/arm/helper.c
> index 96301930cc8..ec56becc394 100644
> --- a/target/arm/helper.c
> +++ b/target/arm/helper.c
> @@ -10560,18 +10560,6 @@ static bool get_phys_addr_pmsav8(CPUARMState *env, uint32_t address,
>   
>       ret = pmsav8_mpu_lookup(env, address, access_type, mmu_idx, phys_ptr,
>                               txattrs, prot, &mpu_is_subpage, fi, NULL);
> -    /*
> -     * TODO: this is a temporary hack to ignore the fact that the SAU region
> -     * is smaller than a page if this is an executable region. We never
> -     * supported small MPU regions, but we did (accidentally) allow small
> -     * SAU regions, and if we now made small SAU regions not be executable
> -     * then this would break previously working guest code. We can't
> -     * remove this until/unless we implement support for execution from
> -     * small regions.
> -     */
> -    if (*prot & PAGE_EXEC) {
> -        sattrs.subpage = false;
> -    }
>       *page_size = sattrs.subpage || mpu_is_subpage ? 1 : TARGET_PAGE_SIZE;
>       return ret;
>   }
>