Re: [PATCH v2 1/5] OvmfPkg/OvmfXen: set PcdAcpiS3Enable at initialization

["Anthony PERARD" <anthony.perard@citrix.com>]

On Fri, Aug 13, 2021 at 02:13:01PM +0800, Gary Lin wrote:
> There are several functions in OvmfPkg/Library using
> QemuFwCfgS3Enabled() to detect the S3 support status. However, in
> MdeModulePkg, PcdAcpiS3Enable is used to check S3 support. Since
> InitializeXenPlatform() didn't set PcdAcpiS3Enable as
> InitializePlatform() did, this made the inconsistency between
> drivers/functions.
> 
> For example, S3SaveStateDxe checked PcdAcpiS3Enable and skipped
> S3BootScript because the default value is FALSE. On the other hand,
> PlatformBootManagerBeforeConsole() from OvmfPkg/Library called
> QemuFwCfgS3Enabled() and found it returned TRUE, so it invoked
> SaveS3BootScript(). However, S3SaveStateDxe skipped S3BootScript, so
> SaveS3BootScript() asserted due to EFI_NOT_FOUND.
> 
> This issue mainly affects "HVM Direct Kernel Boot". If "acpi_s3" is
> set as "True" in xl.cfg, then the S3 Support bit is set and passed
> with fw_cfg.

The part about acpi_s3 isn't true, it doesn't affect fw_cfg.

Maybe this paragraph would be better:

    This issue mainly affects "HVM Direct Kernel Boot". When used,
    "fw_cfg" is enabled in QEMU and QemuFwCfgS3Enabled() returns true in
    that case.

The rest of the patch looks good, thanks.

-- 
Anthony PERARD