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 83E23EB64DD for ; Tue, 27 Jun 2023 08:01:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230400AbjF0IBd (ORCPT ); Tue, 27 Jun 2023 04:01:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48624 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229780AbjF0IB2 (ORCPT ); Tue, 27 Jun 2023 04:01:28 -0400 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C69CE172A; Tue, 27 Jun 2023 01:01:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1687852887; x=1719388887; h=message-id:date:mime-version:cc:subject:to:references: from:in-reply-to:content-transfer-encoding; bh=gM2UbWTRGFSsueosXgYtZzJtPDUlve4cLDttZvEaZdc=; b=lpFW3KX5uswoRBn+tMWH3x1BVyC1Soi89ziOqNGLQFHfety3+kAWXP76 yf6UBo17j7Hh+6fELsYbPg8yO1yYhJbTTEZdiO3buSPB1HE9Gy7akBQHD 0n4zoQd52rbTUV+NEn+VJhpK0yY19ZMtM3yjSZH4WpXWjxNehvNFGqlGm RsE06eqT/YxlByAj8L7BBdPtjO0Nch5kOjLgCPbVVlEkNP11cSyNSIG+4 zAjNX+nt2vgAgqr3+4C1rEgCXnjF/+x9IEGLQhe4AsuLj9Tm0EfYkEuqo P1xyVsuY+9LW4vlPMoH3PilziMifhjTlRcAHVZQcE1muRodzACUbNfaIS g==; X-IronPort-AV: E=McAfee;i="6600,9927,10753"; a="391997473" X-IronPort-AV: E=Sophos;i="6.01,161,1684825200"; d="scan'208";a="391997473" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jun 2023 01:01:27 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10753"; a="746107754" X-IronPort-AV: E=Sophos;i="6.01,161,1684825200"; d="scan'208";a="746107754" Received: from blu2-mobl.ccr.corp.intel.com (HELO [10.254.215.29]) ([10.254.215.29]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jun 2023 01:01:02 -0700 Message-ID: Date: Tue, 27 Jun 2023 16:01:01 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 Cc: baolu.lu@linux.intel.com, "iommu@lists.linux.dev" , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Jason Gunthorpe Subject: Re: [PATCH 1/2] iommu: Prevent RESV_DIRECT devices from blocking domains Content-Language: en-US To: "Tian, Kevin" , "Liu, Jingqi" , Jason Gunthorpe , Joerg Roedel , Will Deacon , Robin Murphy , Alex Williamson , Nicolin Chen References: <20230607035145.343698-1-baolu.lu@linux.intel.com> <20230607035145.343698-2-baolu.lu@linux.intel.com> <8cc1d69e-f86d-fd04-7737-914d967dc0f5@intel.com> <69f50ced-e806-717a-0c74-a4cfa58600fa@linux.intel.com> From: Baolu Lu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 2023/6/27 15:54, Tian, Kevin wrote: >> From: Baolu Lu >> Sent: Tuesday, June 13, 2023 11:15 AM >> >> On 6/12/23 4:28 PM, Liu, Jingqi wrote: >>> On 6/7/2023 11:51 AM, Lu Baolu wrote: >>>> - >>>> -    BUG_ON(!domain->pgsize_bitmap); >>>> - >>>> -    pg_size = 1UL << __ffs(domain->pgsize_bitmap); >>>> +    pg_size = domain->pgsize_bitmap ? 1UL << >>>> __ffs(domain->pgsize_bitmap) : 0; >>> Would it be better to add the following check here? >>>     if (WARN_ON(!pg_size)) >>>             return -EINVAL; >>> >>> Instead of checking latter in the loop as follows. >>>     if (WARN_ON_ONCE(!pg_size)) { >>>             ret = -EINVAL; >>>             goto out; >>>     } >> >> I am afraid no. Only the paging domains need a valid pg_size. That's the >> reason why I put it after the iommu_is_dma_domain() check. The previous >> code has the same behavior too. >> > > You could also add the dma domain check here. pg_size is static > then it makes more sense to verify it once instead of in a loop. Agreed. Does below additional change make sense? diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index e59de7852067..3be88b5f36bb 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -962,6 +962,9 @@ static int iommu_create_device_direct_mappings(struct iommu_domain *domain, pg_size = domain->pgsize_bitmap ? 1UL << __ffs(domain->pgsize_bitmap) : 0; INIT_LIST_HEAD(&mappings); + if (WARN_ON_ONCE((domain->type & __IOMMU_DOMAIN_PAGING) && !pg_size)) + return -EINVAL; + iommu_get_resv_regions(dev, &mappings); /* We need to consider overlapping regions for different devices */ @@ -977,11 +980,6 @@ static int iommu_create_device_direct_mappings(struct iommu_domain *domain, !iommu_is_dma_domain(domain)) continue; - if (WARN_ON_ONCE(!pg_size)) { - ret = -EINVAL; - goto out; - } - start = ALIGN(entry->start, pg_size); end = ALIGN(entry->start + entry->length, pg_size); Best regards, baolu