ACK/cmnt: [Patch 0/2 v2] [impish/linux-azure] Azure: not enough RAM under 4GB for CVM

[Bartlomiej Zolnierkiewicz]

Acked-by: Bartlomiej Zolnierkiewicz <bartlomiej.zolnierkiewicz at canonical.com>

This is under the assumption that the Azure host doesn't provide (on
any instance) devices with the addressing limitations which would
require a 4G limited swiotlb buffer.

Also it seems that the patch #2 should have "UBUNTU: SAUCE: azure:" in
the patch subject (just like it is present in the patch #1).

On Mon, Apr 4, 2022 at 3:17 PM Tim Gardner <tim.gardner at canonical.com> wrote:
>
> v2 - attach the 2nd patch which was forgotten the first time.
>
> SRU Justification
>
> [Impact]
> Can you please include one more patchset for the "no enough RAM under 4GB" issue
> for the v5.13 kernel (and v5.15 kernel):
> https://lwn.net/ml/linux-kernel/20220209122302.213882-2-ltykernel@gmail.com/
> https://lwn.net/ml/linux-kernel/20220209122302.213882-3-ltykernel@gmail.com/
>
> Without the two patches, currently the 5.13 kernel (and 5.15 kernel) can't boot
> as a CVM guest on Azure. :-(
>
> The background is: currently an Azure host only provides about 900 MB memory below
> the 4GB boundary while the swiotlb code (which is required by the CVM patchset)
> needs to allocate memory of a size of MIN(1GB, 6% of the total memory). There will
> be an Azure host update, with which the host will provide about 3GB memory below
> the 4GB boundary, but we still need to wait a few more weeks to know the ETA.
> Currently the above two patches can work around the issue from the guest side.
>
> [Test Case]
>
> Microsoft tested
>
> [Where things could go wrong]
>
> These patches could affect non-CVM instances.
>
> [Other Info]
>
> SF: #00323683