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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 D79F0C07E8C for ; Tue, 8 Aug 2023 16:24:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=kVmyGVOXNuU1y8YzMNWcC8T3Ca4YhasxiXEEMlTkuzM=; b=gizdVZxXmDkgl3 benhrkCak6uHaTm06ajpX+IfYDluRYaUeirU9dfHveqFhnjmLTghaNN9ySoMF/+8xdwRik1XbLOcs GPuVvpU/+ZZO+qLcGGFMGKRaSNOKEhYO0I6TU6/6olK03H6AHHIFFs4oHUSkpUyChMH0jnxS/0FPq 2dwdXbpoGY0OadH3tLTAiw2HPCntHzdFlQbMbNLQHIWeWMblE/UqeMosr13ekpm3vvGFHhAToXS5C F4FaAWb01A9a9eZgDTuPjzcpxOwqTs1couF1z3H1W6pZ37EhN1KkECNOZx+UOSgJ/DMg5Ouhd7gqh hwIzS3JO7aHK5nmHtqAA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qTPVN-002y7Z-0O; Tue, 08 Aug 2023 16:24:21 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qTPVJ-002y6i-0U for linux-arm-kernel@lists.infradead.org; Tue, 08 Aug 2023 16:24:18 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id AE2B9626C7; Tue, 8 Aug 2023 16:24:16 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F2A6EC433C8; Tue, 8 Aug 2023 16:24:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1691511856; bh=nxSmIOL5qjRZRU274MyOK6H5oL/jQ2+CLVvznp2uEZ0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HLmREFugsbR6nwJmsVEKAK0aC+BEa76IK5JRxL5HLUMWJbHk0+SGsppB8NMfQd7xi UJ9TObJm6W+QODEahxUu8odiAqWkfrGXsaCBWthaTlW6XnKGvv1i3VmuJeFk1JvXcR D9FZktBhqR6DiOel4LTED6XsBwPqwOnGGgMxTmj+CdvXcQJw95jwx0xrAUmDENGew7 5Za4VYRckQsVS12IjlsaQ9vCFHZEouH34D0hIeE5PWYO8GnzzM8To8c/6pvB2qATwx IDG55gpGP+rxNXAO5HESD4TArDTm9O7TKf+3nGnZMRLtJ67WmxIEdP2A/SJMwZb9W4 gKg1P/MlM8ygQ== Date: Tue, 8 Aug 2023 17:24:10 +0100 From: Will Deacon To: Robin Murphy Cc: zhurui , Nicolin Chen , linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, Joerg Roedel , Lu Baolu , Jason Gunthorpe , Yicong Yang , Tomas Krcka , Jean-Philippe Brucker Subject: Re: [PATCH v2 1/1] iommu/arm-smmu-v3: Fix error case of range command Message-ID: <20230808162409.GB2890@willie-the-truck> References: <1690784482-30028-1-git-send-email-wangwudi@hisilicon.com> <20230801085504.GA26130@willie-the-truck> <27c895b8-1fb0-be88-8bc3-878d754684c8@huawei.com> <20230804165225.GF30679@willie-the-truck> <015b4573-9d74-451b-8028-a1050ade7019@huawei.com> <661a7bb5-99e1-de16-d860-0cd17f7a0470@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <661a7bb5-99e1-de16-d860-0cd17f7a0470@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230808_092417_271217_5DFF3C01 X-CRM114-Status: GOOD ( 34.77 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Robin, On Mon, Aug 07, 2023 at 08:20:45PM +0100, Robin Murphy wrote: > On 2023-08-06 06:28, zhurui wrote: > > On 2023/8/5 2:30, Nicolin Chen wrote: > > > On Fri, Aug 04, 2023 at 05:52:25PM +0100, Will Deacon wrote: > > > > On Fri, Aug 04, 2023 at 05:31:20PM +0800, zhurui wrote: > > > > > When tg != 0 but ttl, scale, num all 0 in a range tlbi command, it > > > > > is reserved and will cause the CERROR_ILL error. This case means > > > > > that the size to be invalidated is only one page size, and the > > > > > range invalidation is meaningless here. So we set tg to 0 in this > > > > > case to do an non-range invalidation instead. > > > > > > > > @@ -1930,6 +1927,12 @@ static void __arm_smmu_tlb_inv_range(struct arm_smmu_cmdq_ent *cmd, > > > > > num = (num_pages >> scale) & CMDQ_TLBI_RANGE_NUM_MAX; > > > > > cmd->tlbi.num = num - 1; > > > > > > > > > > + /* Prevent error caused by one page tlbi with leaf 0 */ > > > > > + if (scale == 0 && num == 1 && cmd->tlbi.leaf == 0) > > > > > + cmd->tlbi.tg = 0; > > > > > > > > This should only be true for the last iteration, right (i.e. when num_pages > > > > == 1)? In which case, I'd prefer to leave the old code as-is and just add: > > > > > > > > /* Single-page leaf invalidation requires a TG field of 0 */ > > > > if (num_pages == 1 && !cmd->tlbi.leaf) > > > > cmd->tlbi.tg = 0;To Will and Nicolin, > > > > Not only the last iteration, it's the result of __ffs function. For example, if > > numpages is 33, then the value of __ffs(num_pages) is 0, so the value of scale > > is also 0. The value of num depends on CMDQ_TLBI_RANGE_NUM_MAX. That is, the > > maximum value of num is 31. Therefore, the final value of num is 1. > > So, if consider CMDQ_TLBI_RANGE_NUM_MAX, there will be some case not the last > > one page but the beginning pages. That's why I use scale and num as conditions, > > not num_pages. Then I should reassign tg based on the result. > > Yeah, I'd rather not downgrade to a non-range invalidate since that > complicates the reasoning for the errata affecting those. If the size of the > invalidation is equal to TG then it can only represent a single last-level > page, i.e. TTL=3, thus if it does warrant handling here then indeed > rearranging to base the condition on num_pages as well ought to suffice. > However, this is all still begging the question of where and why we're doing > a *non-leaf* invalidation that isn't aligned to the size of a table, because > that in itself doesn't make a whole heap of sense - my hunch is that that > wants figuring out and could probably be fixed at the source. Isn't that described above because we're using CMDQ_TLBI_RANGE_NUM_MAX to break up the range into separate commands? Do you mind if I queue the patch as-is for now? I don't think the driver should be emitting illegal commands, and v2 of the patch does seem like the obvious thing to do. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel