From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from foss.arm.com (foss.arm.com [217.140.110.172])
 by mx.groups.io with SMTP id smtpd.web10.9773.1603698172779736582
 for <devel@edk2.groups.io>;
 Mon, 26 Oct 2020 00:42:53 -0700
Authentication-Results: mx.groups.io;
 dkim=missing; spf=pass (domain: arm.com, ip: 217.140.110.172, mailfrom: ard.biesheuvel@arm.com)
Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14])
	by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B0FC5101E;
	Mon, 26 Oct 2020 00:42:49 -0700 (PDT)
Received: from [192.168.1.81] (unknown [172.31.20.19])
	by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id EAAA13F68F;
	Mon, 26 Oct 2020 00:42:47 -0700 (PDT)
Subject: =?UTF-8?B?UmU6IOWbnuWkjTog5Zue5aSNOiBbZWRrMi1kZXZlbF0gW1BBVENIIDEvM10gTWRlTW9kdWxlUGtnL0FjcGlUYWJsZUR4ZTogdXNlIHBvb2wgYWxsb2NhdGlvbnMgd2hlbiBwb3NzaWJsZQ==?=
To: Laszlo Ersek <lersek@redhat.com>, gaoliming <gaoliming@byosoft.com.cn>,
 devel@edk2.groups.io
Cc: 'Dandan Bi' <dandan.bi@intel.com>, 'Jian J Wang' <jian.j.wang@intel.com>,
 'Hao A Wu' <hao.a.wu@intel.com>, 'Sami Mujawar' <sami.mujawar@arm.com>,
 'Leif Lindholm' <leif@nuviainc.com>
References: <20201016154923.21260-1-ard.biesheuvel@arm.com>
 <20201016154923.21260-2-ard.biesheuvel@arm.com>
 <f2c208c0-7680-c789-3ccd-d298b3963d3a@redhat.com>
 <009401d6a817$53da54e0$fb8efea0$@byosoft.com.cn>
 <bededbf0-a4e1-5f20-671b-c558897e897e@arm.com>
 <003401d6ab38$411f31d0$c35d9570$@byosoft.com.cn>
 <b58d3b6b-40ff-1d0d-a15b-17acb898f0ba@redhat.com>
From: "Ard Biesheuvel" <ard.biesheuvel@arm.com>
Message-ID: <756ec3e7-a1df-8251-f284-07b7aa45ef7f@arm.com>
Date: Mon, 26 Oct 2020 08:42:37 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101
 Thunderbird/68.10.0
MIME-Version: 1.0
In-Reply-To: <b58d3b6b-40ff-1d0d-a15b-17acb898f0ba@redhat.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit

On 10/26/20 7:25 AM, Laszlo Ersek wrote:
> On 10/26/20 02:35, gaoliming wrote:
>> Ard:
>>    I verify this patch on OvmfX64 and collect the memmap info. I don't see the difference in memmap.
>>    So, this enhancement is for AARCH64 only. Is it right?
> 
> That's my understanding, yes. OVMF enables ACPI 1.0b support in the
> bitmask PCD, and so the compat code for 32-bit allocations (= page
> allocations for expressing the 4GB limit) remains active.
> 

Indeed. Any platform that removes BIT1 from

gEfiMdeModulePkgTokenSpaceGuid.PcdAcpiExposedTableVersions

will switch over to pool allocations, but OVMF retains support for ACPI 
1.0b for some reason.