Re: [PATCH] OvmfPkg/PlatformDebugLibIoPort: fix port detection for use in the DXE Core

[Brijesh Singh <brijesh.singh@amd.com>]

On 08/02/2018 07:30 PM, Laszlo Ersek wrote:
> The DXE Core is one of those modules that call
> ProcessLibraryConstructorList() manually.
> 
> Before DxeMain() [MdeModulePkg/Core/Dxe/DxeMain/DxeMain.c] calls
> ProcessLibraryConstructorList(), and through it, our
> PlatformDebugLibIoPortConstructor() function, DxeMain() invokes the
> DEBUG() macro multiple times. That macro lands in our
> PlatformDebugLibIoPortFound() function -- which currently relies on the
> "mDebugIoPortFound" global variable that has (not yet) been set by the
> constructor. As a result, early debug messages from the DXE Core are lost.
> 
> Move the device detection into PlatformDebugLibIoPortFound(), also caching
> the fact (not just the result) of the device detection.
> 
> (We could introduce a separate DebugLib instance just for the DXE Core,
> but the above approach works for all modules that currently consume the
> PlatformDebugLibIoPort instance (which means "everything but SEC").)
> 
> This restores messages such as:
> 
>> CoreInitializeMemoryServices:
>>    BaseAddress - 0x7AF21000 Length - 0x3CDE000 MinimalMemorySizeNeeded - 0x10F4000
> 
> Keep the empty constructor function -- OVMF's DebugLib instances have
> always had constructors; we had better not upset constructor dependency
> ordering by making our instance(s) constructor-less.
> 
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: Brijesh Singh <brijesh.singh@amd.com>
> Cc: Jordan Justen <jordan.l.justen@intel.com>
> Fixes: c09d9571300a089c35f5df2773b70edc25050d0d
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Laszlo Ersek <lersek@redhat.com>
> ---
> 
> Notes:
>      Brijesh, can you please test this patch on SEV, with and without
>      capturing the debug port? (In the first case, the debug log should just
>      work; in the second case, the boot should remain fast.) Thanks!


I have tested the patch on SEV and it works well with and without the 
debug flag. thank you!

Tested-by: Brijesh Singh <brijesh.singh@amd.com>