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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B9B66EB8FA5 for ; Wed, 6 Sep 2023 05:05:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236129AbjIFFFK (ORCPT ); Wed, 6 Sep 2023 01:05:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36392 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230330AbjIFFFI (ORCPT ); Wed, 6 Sep 2023 01:05:08 -0400 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 95B9CC2 for ; Tue, 5 Sep 2023 22:05:04 -0700 (PDT) Received: from [172.20.10.67] (c-73-118-245-227.hsd1.wa.comcast.net [73.118.245.227]) by linux.microsoft.com (Postfix) with ESMTPSA id 96176212B18B; Tue, 5 Sep 2023 22:05:03 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 96176212B18B DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1693976703; bh=KKgsOAhDKOzqo69u3zNX41ZaU+WuV4X01q+Ns+I6CPo=; h=Date:From:Subject:To:Cc:References:In-Reply-To:From; b=UyxQbLMEeAft8ZsE9dSu91CV3ja8JNP91tt6A0MTemXqt7rdrukHq+eTWnxn9RHjB 24IZID5a4WJ8tadEz77nrnf3tjtatmlE8P5aA+iAAkrSitfbbqgLw2Iq1wgYpdFATn z+dcYXDV0XqmbjZzep9IfxNd2hjRvNzgGNlV9q7w= Message-ID: Date: Tue, 5 Sep 2023 22:05:04 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.15.0 From: Easwar Hariharan Subject: Re: [PATCH v2 1/1] iommu/arm-smmu-v3: Fix error case of range command To: zhurui , Will Deacon , Robin Murphy Cc: 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 References: <20230804165225.GF30679@willie-the-truck> <015b4573-9d74-451b-8028-a1050ade7019@huawei.com> <661a7bb5-99e1-de16-d860-0cd17f7a0470@arm.com> <20230808162409.GB2890@willie-the-truck> <80ead8ee-4dbe-7b3c-44f5-944073a2a39d@arm.com> <412886be-644a-5b46-9bfa-1c9a358f9a5d@huawei.com> <280d0be7-7d41-ed78-bf4b-3db6c0076e22@arm.com> <197e87cd-91a2-dce8-716c-488b379abbaf@arm.com> <20230818162114.GB16216@willie-the-truck> Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/25/23 01:12, zhurui wrote: > On 2023/8/19 0:21, Will Deacon wrote: >> On Fri, Aug 18, 2023 at 05:19:31PM +0100, Robin Murphy wrote: >>> On 2023-08-09 14:48, Robin Murphy wrote: >>> [...] >>>> Does the patch below work for you? >>> >>> Any comments on this? Just noticed this commit on a local dev branch and >>> realised I'd totally forgotten about it already. I'm pretty confident it >>> ought to be right, but then it *was* also me who missed the original bug to >>> begin with... ;) >> >> I'm happy to take it if zhurui can confirm that it fixes their issue... >> >> Will (had also forgotten about this) >> >>>> ----->8----- >>>> Subject: [PATCH] iommu/arm-smmu-v3: Avoid constructing invalid range >>>> commands >>>> >>>> Although io-pgtable's non-leaf invalidations are always for full tables, >>>> I missed that SVA also uses non-leaf invalidations, while being at the >>>> mercy of whatever range the MMU notifier throws at it. This means it >>>> definitely wants the previous TTL fix as well, since it also doesn't >>>> know exactly which leaf level(s) may need invalidating, but it can also >>>> give us less-aligned ranges wherein certain corners may lead to building >>>> an invalid command where TTL, Num and Scale are all 0. It should be fine >>>> to handle this by over-invalidating an extra page, since falling back to >>>> a non-range command opens up a whole can of errata-flavoured worms. >>>> >>>> Fixes: 6833b8f2e199 ("iommu/arm-smmu-v3: Set TTL invalidation hint better") >>>> Reported-by: Rui Zhu >>>> Signed-off-by: Robin Murphy >>>> --- >>>>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 15 ++++++++++----- >>>>  1 file changed, 10 insertions(+), 5 deletions(-) >>>> >>>> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >>>> b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >>>> index 9b0dc3505601..6ccbae9b93a1 100644 >>>> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >>>> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >>>> @@ -1895,18 +1895,23 @@ static void __arm_smmu_tlb_inv_range(struct >>>> arm_smmu_cmdq_ent *cmd, >>>>          /* Get the leaf page size */ >>>>          tg = __ffs(smmu_domain->domain.pgsize_bitmap); >>>> >>>> +        num_pages = size >> tg; >>>> + >>>>          /* Convert page size of 12,14,16 (log2) to 1,2,3 */ >>>>          cmd->tlbi.tg = (tg - 10) / 2; >>>> >>>>          /* >>>> -         * Determine what level the granule is at. For non-leaf, >>>> io-pgtable >>>> -         * assumes .tlb_flush_walk can invalidate multiple levels at once, >>>> -         * so ignore the nominal last-level granule and leave TTL=0. >>>> +         * Determine what level the granule is at. For non-leaf, both >>>> +         * io-pgtable and SVA pass a nominal last-level granule because >>>> +         * they don't know what level(s) actually apply, so ignore that >>>> +         * and leave TTL=0. However for various errata reasons we still >>>> +         * want to use a range command, so avoid the SVA corner case >>>> +         * where both scale and num could be 0 as well. >>>>           */ >>>>          if (cmd->tlbi.leaf) >>>>              cmd->tlbi.ttl = 4 - ((ilog2(granule) - 3) / (tg - 3)); >>>> - >>>> -        num_pages = size >> tg; >>>> +        else if ((num_pages & CMDQ_TLBI_RANGE_NUM_MAX) == 1) >>>> +            num_pages++; >>>>      } >>>> >>>>      cmds.num = 0; >>>> > > Hi, Will and Robin, > Sorry for taking so long to reply you. We have some problems with our machine these days. It's > solved just today. I give a test with Robin's patch for our testcase, everything is ok. I think > the problem has been solved. > > Thanks, > ZhuRui. > Hi Robin, Could you please send out this patch since ZhuRui has confirmed it fixes their issue and CC it to stable for v5.15+? Or if Will is willing to pick it up off this thread, I can do the backport to stable. -- Thanks, Easwar