From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3D1F37C for ; Sat, 4 Feb 2023 03:43:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1675482187; x=1707018187; h=message-id:date:mime-version:cc:subject:to:references: from:in-reply-to:content-transfer-encoding; bh=uMsa6W80lQBbzaUuhOxR/OchovtSZ5wheoHgf4HWRHM=; b=JuJwDJ6c9lfH5NJ5KnBbSDePzJHo7dTEKzp0810Q6OiTAm7xIwm9mD9o ADf2NPzImChWH5mHDZEUaCv1eAk44ppzOI6IVq5d2afTyTGvqAF7JNFDa VUB3tGLy6t/I5l9IoWp0IMsJ8mAx/veHGJfUtV1ZPtW2VHq6BVbuUsfZ9 ogn63IGbctFF9DnDqjtb5COPHqssuR2Ci+4hk42H2ouLPQIyDpYcpkoZ2 5rLwWDb5CYp2GrM83vGzCtTxfhgjZWIcovj6xtH38Elq3HcqxG24KZhNL l/zpYttgrEyvqHh3CpysUk0isfSrY3daTxKVtnAjHd5RF8Yw1lb53Idj2 g==; X-IronPort-AV: E=McAfee;i="6500,9779,10610"; a="356258917" X-IronPort-AV: E=Sophos;i="5.97,272,1669104000"; d="scan'208";a="356258917" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Feb 2023 19:43:06 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10610"; a="808552631" X-IronPort-AV: E=Sophos;i="5.97,272,1669104000"; d="scan'208";a="808552631" Received: from blu2-mobl.ccr.corp.intel.com (HELO [10.249.174.222]) ([10.249.174.222]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Feb 2023 19:43:04 -0800 Message-ID: Date: Sat, 4 Feb 2023 11:43:01 +0800 Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.6.1 Cc: baolu.lu@linux.intel.com, David Woodhouse , Raj Ashok , "Tian, Kevin" , Yi Liu , stable@vger.kernel.org, Sukumar Ghorai Subject: Re: [PATCH] iommu/vt-d: Fix PASID directory pointer coherency Content-Language: en-US To: Jacob Pan , LKML , iommu@lists.linux.dev, Joerg Roedel References: <20230203220714.1283383-1-jacob.jun.pan@linux.intel.com> From: Baolu Lu In-Reply-To: <20230203220714.1283383-1-jacob.jun.pan@linux.intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2023/2/4 6:07, Jacob Pan wrote: > On platforms that do not support IOMMU Extended capability bit 0 > Page-walk Coherency, CPU caches are not snooped when IOMMU is accessing > any translation structures. IOMMU access goes only directly to > memory. Intel IOMMU code was missing a flush for the PASID table > directory that resulted in the unrecoverable fault as shown below. Thanks for the fix. > This patch adds a clflush when activating a PASID table directory. > There's no need to do clflush of the PASID directory pointer when we > deactivate a context entry in that IOMMU hardware will not see the old > PASID directory pointer after we clear the context entry. > > [ 0.555386] DMAR: DRHD: handling fault status reg 3 > [ 0.555805] DMAR: [DMA Read NO_PASID] Request device [00:0d.2] fault addr 0x1026a4000 [fault reason 0x51] SM: Present bit in Directory Entry is clear > [ 0.556348] DMAR: Dump dmar1 table entries for IOVA 0x1026a4000 > [ 0.556348] DMAR: scalable mode root entry: hi 0x0000000102448001, low 0x0000000101b3e001 > [ 0.556348] DMAR: context entry: hi 0x0000000000000000, low 0x0000000101b4d401 > [ 0.556348] DMAR: pasid dir entry: 0x0000000101b4e001 > [ 0.556348] DMAR: pasid table entry[0]: 0x0000000000000109 > [ 0.556348] DMAR: pasid table entry[1]: 0x0000000000000001 > [ 0.556348] DMAR: pasid table entry[2]: 0x0000000000000000 > [ 0.556348] DMAR: pasid table entry[3]: 0x0000000000000000 > [ 0.556348] DMAR: pasid table entry[4]: 0x0000000000000000 > [ 0.556348] DMAR: pasid table entry[5]: 0x0000000000000000 > [ 0.556348] DMAR: pasid table entry[6]: 0x0000000000000000 > [ 0.556348] DMAR: pasid table entry[7]: 0x0000000000000000 > [ 0.556348] DMAR: PTE not present at level 4 > > Cc: > Reported-by: Sukumar Ghorai > Signed-off-by: Ashok Raj > Signed-off-by: Jacob Pan Add a Fixes tag so that people know how far this fix should be back ported. > --- > drivers/iommu/intel/iommu.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c > index 59df7e42fd53..b4878c7ac008 100644 > --- a/drivers/iommu/intel/iommu.c > +++ b/drivers/iommu/intel/iommu.c > @@ -1976,6 +1976,12 @@ static int domain_context_mapping_one(struct dmar_domain *domain, > pds = context_get_sm_pds(table); > context->lo = (u64)virt_to_phys(table->table) | > context_pdts(pds); > + /* > + * Scalable-mode PASID directory pointer is not snooped if the > + * coherent bit is not set. > + */ > + if (!ecap_coherent(iommu->ecap)) > + clflush_cache_range(table->table, sizeof(void *)); This isn't comprehensive. The clflush should be called whenever the pasid directory table is allocated or updated. > > /* Setup the RID_PASID field: */ > context_set_sm_rid2pasid(context, PASID_RID2PASID); Best regards, baolu