Re: [PATCH v2 3/4] ArmPkg/ArmDmaLib: clean up abuse of device address

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On 15 November 2016 at 11:34, Ryan Harkin <ryan.harkin@linaro.org> wrote:
> On 15 November 2016 at 09:19, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
>> On 14 November 2016 at 16:16, Leif Lindholm <leif.lindholm@linaro.org> wrote:
>>> On Sat, Nov 12, 2016 at 02:02:27PM +0100, Ard Biesheuvel wrote:
>>>> In preparation of adding support to ArmDmalib for DMA bus masters whose
>>>> view of memory is offset by a constant compared to the CPU's view, clean
>>>> up some abuse of the device address.
>>>>
>>>> The device address is not defined in terms of the CPU's address space,
>>>> and so it should not be used in CopyMem () or cache maintenance operations
>>>> that require a valid mapping. This not only applies to the above use case,
>>>> but also to the DebugUncachedMemoryAllocationLib that unmaps the
>>>> primary, cached mapping of an allocation, and returns a host address
>>>> which is an uncached alias offset by a constant.
>>>>
>>>> Since we should never access the device address from the CPU, there is
>>>> no need to record it in the MAPINFO struct. Instead, record the buffer
>>>> address in case of double buffering, since we do need to copy the contents
>>>> (in case of a bus master write) and free the buffer (in all cases) when
>>>> DmaUnmap() is called.
>>>>
>>>> Contributed-under: TianoCore Contribution Agreement 1.0
>>>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>>>
>>> For the fix itself:
>>> Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
>>>
>>> However, can we wait for a few Tested-by:s to ensure this fix does not
>>> reveal any companion bugs?
>>>
>>
>> Perhaps, yes.
>>
>> In case anyone is up to doing that, please find the branch here
>> https://git.linaro.org/people/ard.biesheuvel/uefi-next.git/log/?h=armdmalib-offset
>>
>
> I tested your branch on the usual victims (R0/1/2, FVP Foundation &
> AEMv8 and TC2) and they all work fine for me.
>
> Tested-by: Ryan Harkin <ryan.harkin@linaro.org>
>

Thanks!