From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by mx.groups.io with SMTP id smtpd.web10.1561.1620241869501558036 for ; Wed, 05 May 2021 12:11:09 -0700 Authentication-Results: mx.groups.io; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=Ongx4cI0; spf=pass (domain: redhat.com, ip: 216.205.24.124, mailfrom: lersek@redhat.com) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1620241868; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=O7bPJahJCPkLcYwRErcTsjvzT+HKBuM2AlFINbjE8TI=; b=Ongx4cI0zubnWIHoW/7Z9kWYYXYvRZKK7zvsIQN+3ojFb7ZdcDh5F1sfTGqv92CyHMtE/F OOKnCLsz/FpdDmIDxgYR7BHiUSZ7vEPKl3ei4rPg9foDCowa9YyoLnCkUGgKSWBzQ5EgNJ qCdovLhpvQQB92FE2uhkYM0Zadwgb2Q= 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-323-YnOh2v2gP8KvyR4kC9rd3g-1; Wed, 05 May 2021 15:11:05 -0400 X-MC-Unique: YnOh2v2gP8KvyR4kC9rd3g-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6703710066E6; Wed, 5 May 2021 19:11:03 +0000 (UTC) Received: from lacos-laptop-7.usersys.redhat.com (ovpn-113-136.ams2.redhat.com [10.36.113.136]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6F79710074E5; Wed, 5 May 2021 19:11:00 +0000 (UTC) Subject: Re: [edk2-devel] [PATCH RFC v2 05/28] MdePkg: Add AsmPvalidate() support To: devel@edk2.groups.io, brijesh.singh@amd.com Cc: James Bottomley , Min Xu , Jiewen Yao , Tom Lendacky , Jordan Justen , Ard Biesheuvel , Erdem Aktas References: <20210430115148.22267-1-brijesh.singh@amd.com> <20210430115148.22267-6-brijesh.singh@amd.com> <167BF2A01FA60569.6407@groups.io> <90dec0ee-0d4b-e72e-ce4d-b8b8e69f2b80@amd.com> From: "Laszlo Ersek" Message-ID: <5475b7d2-cddb-96a5-553a-32bebc434083@redhat.com> Date: Wed, 5 May 2021 21:10:59 +0200 MIME-Version: 1.0 In-Reply-To: <90dec0ee-0d4b-e72e-ce4d-b8b8e69f2b80@amd.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=lersek@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 05/04/21 21:55, Brijesh Singh wrote: > > On 5/4/21 2:07 PM, Brijesh Singh via groups.io wrote: >>> Return EFI_UNSUPPORTED (0x8000_0003), or even EFI_NO_MAPPING >>> (0x8000_0017), for value 6 (FAIL_SIZEMISMATCH). >> I am not sure if we really want to do this. You will see later in the >> patches that in some cases the PVALIDATE will return a failure and we >> will need to know the failure code to determine the next steps. >> Especially this particular error code is used later. This error happens >> when the page size of the backing pages does not match with the >> pvalidated size. In those cases we need to retry the PVALIDATE with >> lower page size so that a validation succeed. One such a example is: >> >> - Guest ask hypervisor to add the page as 2M in RMP table. >> >> - Hypervisor added the page as 512 4K pages - because it was not able to >> find a large backing pages. >> >> - Guest attempts to pvalidate the page as a 2M. The pvalidate will >> return a failure saying its a size mismatch between the requested >> pvalidated and RMP table. The recommendation is that guest should try >> with a smaller page size. >> >> I would prefer to pass the pvalidate error as-is to caller so that it >> can make the correct decision. >> > I am perfectly fine if the function return UINTN and then use #define > instead of the enum to define the PVALIDATE return code. So that caller > can check the error code. Let me know your thought on #define instead of > the enum. (1) If the funcion returns UINTN rather than an enum type, that resolves my request, technically speaking. I think it's inferior to the EFI_STATUS mapping that I proposed, but it certainly resolves my request! (2) How you provide the symbolic names for the values 0, 1, 6, does not matter. If you use #define's (= macros), that's fine. If you use an enum type, with enum constants, that's also fine. This aspect is orthogonal to my request. Thanks! Laszlo