Re: [PATCH] OvmfPkg/OvmfXen: Fix S3

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

Hi Xenia,

On Thu, Jul 13, 2023 at 01:47:12PM +0300, Xenia Ragiadakou wrote:
> Currently, resuming an S3 suspended guest results in the following
> assertion failure:
> ASSERT 
> MdePkg/Library/PeiResourcePublicationLib/PeiResourcePublicationLib.c(41): 
> MemoryLength > 0
> This happens because some parts of the S3 suspend and resume paths
> are missing in order for S3 to work. For instance, the variables
> mS3AcpiReservedMemoryBase and mS3AcpiReservedMemoryBase are not
> initialized, regions that are used on S3 resume are either missing
> or not marked as ACPI NVS memory and can be corrupted by the OS.
> This patch adds the missing parts based heavily on the existing S3
> implementation of other virtual platforms.
> 
> For S3 support, the provision of fw_cfg is required in order for
> suspend states to be retrieved.

Is it possible to have S3 work without fw_cfg? We normally disable
fw_cfg in QEMU when using it to start a Xen guest. We only enable fw_cfg
if we want to boot a kernel directly in HVM (like PV guest, called
Direct Kernel Boot in xl.cfg(5)).

But even trying the direct kernel boot method, I've got issue trying to
resume a suspended guest. I ran into:
    ASSERT /root/build/ovmf/UefiCpuPkg/Library/MpInitLib/MpLib.c(2093): 
(LibPcdGet64(9U) & (0x00000001 | 0x00000002)) == (0x00000001 | 0x00000002)

By the way, I'm using `xl` to boot a guest to test this patch.

So, I've got some question, which version of QEMU do you use, which work
with this patch?
What toolstack do you use to boot a guest?


Thanks,

-- 
Anthony PERARD