Re: [Qemu-devel] [PATCH v1 05/22] target-arm: Add arm_el_to_mmu_idx()

[Alexander Graf <agraf@suse.de>]

On 17.05.14 00:10, Edgar E. Iglesias wrote:
> On Fri, May 16, 2014 at 03:24:42PM +0100, Peter Maydell wrote:
>> On 6 May 2014 07:08, Edgar E. Iglesias <edgar.iglesias@gmail.com> wrote:
>>> From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com>
>>>
>>> Maps a given EL to the corresponding MMU index.
>>>
>>> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
>>> ---
>>>   target-arm/cpu.h           | 21 ++++++++++++++++++++-
>>>   target-arm/translate-a64.c |  8 ++------
>>>   2 files changed, 22 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/target-arm/cpu.h b/target-arm/cpu.h
>>> index ff86250..938f389 100644
>>> --- a/target-arm/cpu.h
>>> +++ b/target-arm/cpu.h
>>> @@ -1086,9 +1086,28 @@ static inline CPUARMState *cpu_init(const char *cpu_model)
>>>   #define MMU_MODE0_SUFFIX _kernel
>>>   #define MMU_MODE1_SUFFIX _user
>>>   #define MMU_USER_IDX 1
>>> +static inline int arm_el_to_mmu_idx(int current_el)
>>> +{
>>> +#ifdef CONFIG_USER_ONLY
>>> +    return MMU_USER_IDX;
>>> +#else
>>> +    switch (current_el) {
>>> +    case 0:
>>> +        return MMU_USER_IDX;
>>> +    case 1:
>>> +        return 0;
>>> +    default:
>>> +        /* Unsupported EL.  */
>>> +        assert(0);
>>> +        return 0;
>>> +    }
>>> +#endif
>> Can we just make the EL and the MMU index the same thing,
>> or is secure-vs-nonsecure going to need its own MMU
>> indexes anyway?
> Right, I did the conversion to 1:1 mapping at an early stage
> but avoided it as we will need an indirect mapping for
> Secure EL0/1 anyway.

How often do we switch between secure and non-secure? If it doesn't 
happen all that often, we could just flush the TLB on every transition.


Alex