From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from ws5-mx01.kavi.com (ws5-mx01.kavi.com [34.193.7.191]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8A8EAEB64D8 for ; Wed, 21 Jun 2023 09:30:59 +0000 (UTC) Received: from lists.oasis-open.org (oasis.ws5.connectedcommunity.org [10.110.1.242]) by ws5-mx01.kavi.com (Postfix) with ESMTP id BE48DEEA06 for ; Wed, 21 Jun 2023 09:30:58 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id A29309865B2 for ; Wed, 21 Jun 2023 09:30:58 +0000 (UTC) Received: from host09.ws5.connectedcommunity.org (host09.ws5.connectedcommunity.org [10.110.1.97]) by lists.oasis-open.org (Postfix) with QMQP id 8EBAE98653D; Wed, 21 Jun 2023 09:30:58 +0000 (UTC) Mailing-List: contact virtio-comment-help@lists.oasis-open.org; run by ezmlm List-ID: Sender: Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 7725C986546 for ; Wed, 21 Jun 2023 09:30:58 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-MC-Unique: pt6xxTdrPEq8meRzc31PKQ-1 From: Cornelia Huck To: Alex =?utf-8?Q?Benn=C3=A9e?= , virtio-comment@lists.oasis-open.org Cc: Alex =?utf-8?Q?Benn=C3=A9e?= , Manos Pitsidianakis , Harald Mommer , Will Deacon In-Reply-To: <20230619120128.234244-1-alex.bennee@linaro.org> Organization: Red Hat GmbH References: <20230619120128.234244-1-alex.bennee@linaro.org> User-Agent: Notmuch/0.37 (https://notmuchmail.org) Date: Wed, 21 Jun 2023 11:30:52 +0200 Message-ID: <87v8fh17sj.fsf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [virtio-comment] [RFC PATCH] virtio-rpmb: fix spec land mine in max_[wr|rd]_cnt On Mon, Jun 19 2023, Alex Benn=C3=A9e wrote: > Even if 0 meant no limit we are still limited by the field size of the > request. That said for a maximum sized partition (* 80 128 1024) you > could only actually request 40960 blocks before running out of device. > Perhaps it would be better to mark 0 as invalid? I don't think we can mark 0 as invalid, as it has been in a published spec and implementations may be already using it. That said, what is the actual limitation? Knowing nothing about RPMB, is it 64k (what can fit in block_count), or the 40960 you mentioned above as a value defined by other reasons (maximum size of a partition -- I assume that cannot change?) > > Cc: Manos Pitsidianakis > Cc: Harald Mommer > Cc: Will Deacon > Signed-off-by: Alex Benn=C3=A9e > --- > device-types/rpmb/description.tex | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/device-types/rpmb/description.tex b/device-types/rpmb/descri= ption.tex > index 1dae3fd..2ce8a5b 100644 > --- a/device-types/rpmb/description.tex > +++ b/device-types/rpmb/description.tex > @@ -37,7 +37,7 @@ \subsection{Device configuration layout}\label{sec:Devi= ce Types / RPMB Device / > The values MUST range between 0x00 and 0x80 inclusive. > \item[\field{max_wr_cnt and max_rd_cnt}] are the maximum numbers of RPMB > block count (256B) that can be performed to device in one request. 0 = implies > - no limitation. > + no limitation other than the maximum value you can store in \field{bl= ock_count} (65535). So, I'm now wondering what these fields actually refer to. They are u8, so obviously less than what fits into be16... are reads/writes limited by anything else? > \end{description} > =20 > \devicenormative{\subsection}{Device Initialization}{Device Types / RPMB= Device / Device Initialization} This publicly archived list offers a means to provide input to the=0D OASIS Virtual I/O Device (VIRTIO) TC.=0D =0D In order to verify user consent to the Feedback License terms and=0D to minimize spam in the list archive, subscription is required=0D before posting.=0D =0D Subscribe: virtio-comment-subscribe@lists.oasis-open.org=0D Unsubscribe: virtio-comment-unsubscribe@lists.oasis-open.org=0D List help: virtio-comment-help@lists.oasis-open.org=0D List archive: https://lists.oasis-open.org/archives/virtio-comment/=0D Feedback License: https://www.oasis-open.org/who/ipr/feedback_license.pdf=0D List Guidelines: https://www.oasis-open.org/policies-guidelines/mailing-lists=0D Committee: https://www.oasis-open.org/committees/virtio/=0D Join OASIS: https://www.oasis-open.org/join/