Re: Exporting discontiguous System Memory to EFI STUB

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

On 21 September 2016 at 12:32, Bhupesh Sharma <bhupesh.sharma@nxp.com> wrote:
> Hi Ard,
>
>> From: Ard Biesheuvel
>> Sent: Wednesday, September 21, 2016 4:50 PM
>>
[...]
>> I recently fixed a problem in the MMU code where the maximum size of
>> the VA range which is programmed into the MMU registers was based on
>> the initial memory size, and adding memory (or MMIO) ranges later would
>> cause problems.
>>
>> WIth the latest EDK2, adding memory may be done at any time, and will
>> be reflected in the 1:1 mapping in the MMU
>
> Thanks. That looks promising. Can you please share the SHA-ID, commit-ID
> of this *MMU fixup* patch.
>

commit dd82465a9f0f0beff0e4d74c6e3192b966853332
Author: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Date:   Fri Sep 9 09:01:56 2016 +0100

    ArmPkg/ArmMmuLib: base page table VA size on GCD memory map size

    As reported by Eugene, the practice of sizing the address space in the
    virtual memory system based on the maximum address in the table passed
    to ArmConfigureMmu() is problematic, since it fails to take into account
    the fact that the GCD memory space may be extended at a later time, both
    for memory and for MMIO. So instead, choose the VA size identical to the
    GCD memory map size, which is based on PcdPrePiCpuMemorySize on ARM
    systems.

    Reported-by: Eugene Cohen <eugene@hp.com>
    Contributed-under: TianoCore Contribution Agreement 1.0
    Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
    Reviewed-by: Eugene Cohen <eugene@hp.com>
    Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>