Re: [edk2-devel] [PATCH v2 1/4] OvmfPkg/Sec: Setup MTRR early in the boot process.

["Laszlo Ersek" <lersek@redhat.com>]

On 1/25/24 11:52, Pedro Falcato wrote:
> On Thu, Jan 25, 2024 at 8:23 AM Gerd Hoffmann <kraxel@redhat.com> wrote:
>>
>> Specifically before running lzma uncompress of the main firmware volume.
>> This is needed to make sure caching is enabled, otherwise the uncompress
>> can be extremely slow.
>>
>> Adapt the ASSERTs and MTRR setup in PlatformInitLib to the changes.
>>
>> Background:  Depending on virtual machine configuration kvm may uses EPT
>> memory types to apply guest MTRR settings.  In case MTRRs are disabled
>> kvm will use the uncachable memory type for all mappings.  Here is the
>> linux kernel function handling this:
> 
> It might not be wise to blat out GPLv2 source code in a commit message
> :) Not that it's a violation of the GPL (we're not linking against it,
> neither can the patch be considered a derivative work), but it might
> just be a little too grey-area for a !GPL project.
> 

I think you are right.

How incredibly annoying.

Perhaps we should replace the vmx_get_mt_mask() quote with a link like...

https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/arch/x86/kvm/vmx/vmx.c?h=v6.7.1#n7580

This link (including a line number) is stable, because it references a tag.

"all problems in computer science can be solved by another layer of
indirection"

https://en.wikipedia.org/wiki/David_Wheeler_(computer_scientist)#Quotes

Funnily enough, Linus would yell at us for this; IIRC he strongly
prefers embedding information over linking information, in commit
messages. :/

Laszlo



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