From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from us-smtp-1.mimecast.com (us-smtp-1.mimecast.com [207.211.31.120])
 by mx.groups.io with SMTP id smtpd.web09.2199.1583442917030650833
 for <devel@edk2.groups.io>;
 Thu, 05 Mar 2020 13:15:17 -0800
Authentication-Results: mx.groups.io;
 dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=RqNG57yI;
 spf=pass (domain: redhat.com, ip: 207.211.31.120, mailfrom: lersek@redhat.com)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com;
	s=mimecast20190719; t=1583442916;
	h=from:from:reply-to:subject:subject:date:date:message-id:message-id:
	 to:to:cc:mime-version:mime-version:content-type:content-type:
	 content-transfer-encoding:content-transfer-encoding:
	 in-reply-to:in-reply-to:references:references;
	bh=8MdMBceigCTcN3DEMfhmRvkypBILGKDxoFnc/cgZ5VQ=;
	b=RqNG57yIQAvE94ECAslpttgP5XOc+cnxXoOb6G9kFP9n2keXvmlnupg4zT83imBhKe7RxT
	bDX9UgJsxJo98P6YvvbLd7LSdJQU+qdbnm+wk8xZmcgzwx7Nh+PLc6mcuO27qy6SBOumHA
	NhnNmmvMlrvSxJJkGEImzxxgMLHvMyo=
Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com
 [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id
 us-mta-3-Z7BF6n3IO9Kie3vQscX5yQ-1; Thu, 05 Mar 2020 16:15:11 -0500
X-MC-Unique: Z7BF6n3IO9Kie3vQscX5yQ-1
Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12])
	(using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))
	(No client certificate requested)
	by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A66D4801E66;
	Thu,  5 Mar 2020 21:15:10 +0000 (UTC)
Received: from lacos-laptop-7.usersys.redhat.com (ovpn-117-216.ams2.redhat.com [10.36.117.216])
	by smtp.corp.redhat.com (Postfix) with ESMTP id EAD0B60C99;
	Thu,  5 Mar 2020 21:15:09 +0000 (UTC)
Subject: Re: [edk2-devel] [PATCH v3 12/14] OvmfPkg/PlatformBootManagerLib: switch to QemuLoadImageLib
To: devel@edk2.groups.io, ard.biesheuvel@linaro.org
References: <20200305134607.20125-1-ard.biesheuvel@linaro.org>
 <20200305134607.20125-13-ard.biesheuvel@linaro.org>
From: "Laszlo Ersek" <lersek@redhat.com>
Message-ID: <5c7e3e2d-d47c-200a-f489-569abec4547d@redhat.com>
Date: Thu, 5 Mar 2020 22:15:09 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
 Thunderbird/52.9.1
MIME-Version: 1.0
In-Reply-To: <20200305134607.20125-13-ard.biesheuvel@linaro.org>
X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12
X-Mimecast-Spam-Score: 0
X-Mimecast-Originator: redhat.com
Content-Language: en-US
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 7bit

Hi Ard,

On 03/05/20 14:46, Ard Biesheuvel wrote:
> Replace the open coded sequence to load Linux on x86 with a short and
> generic sequence invoking QemuLoadImageLib, which can be provided by
> a generic version that only supports the LoadImage and StartImage boot
> services, and one that incorporates the entire legacy loading sequence
> as well.
> 
> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2566
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Reviewed-by: Laszlo Ersek <lersek@redhat.com>
> ---
>  OvmfPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf |   2 +-
>  OvmfPkg/Library/PlatformBootManagerLib/QemuKernel.c               | 144 ++------------------
>  2 files changed, 14 insertions(+), 132 deletions(-)
> 
> diff --git a/OvmfPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf b/OvmfPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf
> index c479f113b92b..e470b9a6a3e5 100644
> --- a/OvmfPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf
> +++ b/OvmfPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf
> @@ -49,7 +49,7 @@ [LibraryClasses]
>    NvVarsFileLib
>    QemuFwCfgLib
>    QemuFwCfgS3Lib
> -  LoadLinuxLib
> +  QemuLoadImageLib
>    QemuBootOrderLib
>    ReportStatusCodeLib
>    UefiLib

This hunk (in commit 859b55443a42) seems to break the OvmfXen platform build:

Active Platform          = OvmfPkg/OvmfXen.dsc

build.py...
OvmfPkg/OvmfXen.dsc(...): error 4000: Instance of library class [QemuLoadImageLib] is not found
        in [OvmfPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf] [X64]
        consumed by module [MdeModulePkg/Universal/BdsDxe/BdsDxe.inf]

Can you please send a patch?

I think resolving the lib class to the generic instance suffices. gBS->LoadImage() will return EFI_NOT_FOUND from QemuLoadKernelImage(), because OvmfPkg/QemuKernelLoaderFsDxe is not included in the Xen platform.

An alternative fix that's larger in source code, but lighter in binary code, would be to add a Null instance of QemuLoadImageLib, and use that in the Xen platform.

For the future, please include OvmfXen.dsc in your build / CI scripts.

Thanks!
Laszlo