[edk2-devel] [PATCH v7 0/7] Add safe unaccepted memory behavior

[Dionna Glaze via groups.io]

On Tue, Oct 25, 2022 at 5:23 PM Alexey Kardashevskiy <aik at ozlabs.ru> wrote:
>
> Hi Dionna,
>
> Thanks for updating the tree, builds nicely now! However the VM's kernel
> does not boot - the guest kernel reports
>
> EFI stub: ERROR: exit_boot() failed!
>
> and hangs. I am not quite sure how it is supposed to work (still
> learning) but "Accepting all memory" happens twice (should it?) and the
> actual reason for the CoreExitBootService() failure is that MapKey !=
> mMemoryMapKey in CoreTerminateMemoryMap(), these are 0x7AD7 vs 0x7AD9
> or  0x7AE1 vs 0x7AE3 (the diff is always 2).
>

"Accepting all memory" may happen twice, but it's idempotent. The
debug_info log happening twice might be confusing, so I can change
that if you'd like.

The first accept will remove all unaccepted memory regions from the
address space map.
CoreExitBootService should fail the first time since the first accept
will change the memory map.
That failure means that the caller should GetMemoryMap again and try
CoreExitBootService again.

> How do you test it exactly, is there any command line change needed in
> addition to enabling SNP?
>
> My guest kernel uses
> https://patchew.org/linux/cover.1664298261.git.thomas.lendacky@amd.com/
> with the TDX prerequisite. Thanks,
>

It's a few name changes behind, but this branch of Linux is what I've
been using:

https://github.com/deeglaze/amdese-linux/tree/v12unacceptedv7v5-enableum

Specific enablement patch here
https://github.com/AMDESE/linux/commit/5a708081d58d773e767b11735ee1fd17ef5e5f61

I incorporate Kirill's patch set v7 for basic unaccepted memory
support, Tom Lendacky's v5 patch set for SEV-SNP support of unaccepted
memory, and I have a single patch that calls the protocol.
This branch doesn't have Kirill's TDX patches.
I've run it with a regular SEV-SNP enabled guest kernel too. At this
point all the tests have used kernel injection rather than having the
kernels all baked into the image.


-- 
-Dionna Glaze, PhD (she/her)


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