accel/tcg: Support execution from MMIO and small MMU regions

[Qemu-devel] [PATCH 6/6] target/arm: Allow execution from small regions

Posted by Peter Maydell 7 years, 7 months ago

Now that we have full support for small regions, including execution,
we can remove the workarounds where we marked all small regions as
non-executable for the M-profile MPU and SAU.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/helper.c | 23 -----------------------
 1 file changed, 23 deletions(-)

diff --git a/target/arm/helper.c b/target/arm/helper.c
index a2ac96084e7..ed96e6c02fb 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -9784,17 +9784,6 @@ static bool get_phys_addr_pmsav7(CPUARMState *env, uint32_t address,
 
     fi->type = ARMFault_Permission;
     fi->level = 1;
-    /*
-     * Core QEMU code can't handle execution from small pages yet, so
-     * don't try it. This way we'll get an MPU exception, rather than
-     * eventually causing QEMU to exit in get_page_addr_code().
-     */
-    if (*page_size < TARGET_PAGE_SIZE && (*prot & PAGE_EXEC)) {
-        qemu_log_mask(LOG_UNIMP,
-                      "MPU: No support for execution from regions "
-                      "smaller than 1K\n");
-        *prot &= ~PAGE_EXEC;
-    }
     return !(*prot & (1 << access_type));
 }
 
@@ -10014,18 +10003,6 @@ static bool pmsav8_mpu_lookup(CPUARMState *env, uint32_t address,
 
     fi->type = ARMFault_Permission;
     fi->level = 1;
-    /*
-     * Core QEMU code can't handle execution from small pages yet, so
-     * don't try it. This means any attempted execution will generate
-     * an MPU exception, rather than eventually causing QEMU to exit in
-     * get_page_addr_code().
-     */
-    if (*is_subpage && (*prot & PAGE_EXEC)) {
-        qemu_log_mask(LOG_UNIMP,
-                      "MPU: No support for execution from regions "
-                      "smaller than 1K\n");
-        *prot &= ~PAGE_EXEC;
-    }
     return !(*prot & (1 << access_type));
 }
 
-- 
2.17.1

Re: [Qemu-devel] [PATCH 6/6] target/arm: Allow execution from small regions

Posted by Richard Henderson 7 years, 7 months ago

On 07/10/2018 09:00 AM, Peter Maydell wrote:
> Now that we have full support for small regions, including execution,
> we can remove the workarounds where we marked all small regions as
> non-executable for the M-profile MPU and SAU.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  target/arm/helper.c | 23 -----------------------
>  1 file changed, 23 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~

Re: [Qemu-devel] [Qemu-arm] [PATCH 6/6] target/arm: Allow execution from small regions

Posted by Philippe Mathieu-Daudé 7 years, 7 months ago

On 07/10/2018 01:00 PM, Peter Maydell wrote:
> Now that we have full support for small regions, including execution,
> we can remove the workarounds where we marked all small regions as
> non-executable for the M-profile MPU and SAU.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

> ---
>  target/arm/helper.c | 23 -----------------------
>  1 file changed, 23 deletions(-)
> 
> diff --git a/target/arm/helper.c b/target/arm/helper.c
> index a2ac96084e7..ed96e6c02fb 100644
> --- a/target/arm/helper.c
> +++ b/target/arm/helper.c
> @@ -9784,17 +9784,6 @@ static bool get_phys_addr_pmsav7(CPUARMState *env, uint32_t address,
>  
>      fi->type = ARMFault_Permission;
>      fi->level = 1;
> -    /*
> -     * Core QEMU code can't handle execution from small pages yet, so
> -     * don't try it. This way we'll get an MPU exception, rather than
> -     * eventually causing QEMU to exit in get_page_addr_code().
> -     */
> -    if (*page_size < TARGET_PAGE_SIZE && (*prot & PAGE_EXEC)) {
> -        qemu_log_mask(LOG_UNIMP,
> -                      "MPU: No support for execution from regions "
> -                      "smaller than 1K\n");
> -        *prot &= ~PAGE_EXEC;
> -    }
>      return !(*prot & (1 << access_type));
>  }
>  
> @@ -10014,18 +10003,6 @@ static bool pmsav8_mpu_lookup(CPUARMState *env, uint32_t address,
>  
>      fi->type = ARMFault_Permission;
>      fi->level = 1;
> -    /*
> -     * Core QEMU code can't handle execution from small pages yet, so
> -     * don't try it. This means any attempted execution will generate
> -     * an MPU exception, rather than eventually causing QEMU to exit in
> -     * get_page_addr_code().
> -     */
> -    if (*is_subpage && (*prot & PAGE_EXEC)) {
> -        qemu_log_mask(LOG_UNIMP,
> -                      "MPU: No support for execution from regions "
> -                      "smaller than 1K\n");
> -        *prot &= ~PAGE_EXEC;
> -    }
>      return !(*prot & (1 << access_type));
>  }
>  
>