From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.126]) (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 26A327E4 for ; Thu, 10 Aug 2023 02:27:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1691634448; x=1723170448; h=message-id:date:mime-version:cc:subject:to:references: from:in-reply-to:content-transfer-encoding; bh=wbX5ZGZU+a045ReN97N8foV8POn+IQFOPh9KTo/LP+c=; b=WdHCsmAhJMGYzQbEeEqkxDz7W7dU4tuJDBP261nCuRBkcYm6zjELb2sh 9Ue9CoWJAzdsGIexcHtlPNw4Mrc42FqVtxSThth6MvZkeE4K59sOPzt/L xd7DweNAc0fyGcY/fuIT5yv9aqiz+LqGJOWwDRWlR7mnSSR7keXKZS2Xw eL6xjj0syHg7/m94PyKmR7/ZQaRKMJ3sVCTK6L+TVF/ccuHdKJleLDG6P v2HMWgYSkiUc9682eOGyjonkYlZuka8HaJZvITlT5E9oS+bj8CGdvY7Pa Vuxb1MuJuNWzjH1Sr4CAyX6+yV3Rg5YgTOXjKvm47DzbDMg8TbxTIeZgF w==; X-IronPort-AV: E=McAfee;i="6600,9927,10797"; a="356244296" X-IronPort-AV: E=Sophos;i="6.01,160,1684825200"; d="scan'208";a="356244296" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Aug 2023 19:27:27 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10797"; a="797433020" X-IronPort-AV: E=Sophos;i="6.01,160,1684825200"; d="scan'208";a="797433020" Received: from blu2-mobl.ccr.corp.intel.com (HELO [10.254.214.239]) ([10.254.214.239]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Aug 2023 19:27:23 -0700 Message-ID: <28d86414-d684-b468-d0a9-5c429260e081@linux.intel.com> Date: Thu, 10 Aug 2023 10:27:21 +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/102.14.0 Cc: baolu.lu@linux.intel.com, Joerg Roedel , Will Deacon , Robin Murphy , Kevin Tian , Jean-Philippe Brucker , Nicolin Chen , Yi Liu , Jacob Pan , iommu@lists.linux.dev, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 03/12] iommu: Remove unrecoverable fault data Content-Language: en-US To: Jason Gunthorpe References: <20230727054837.147050-1-baolu.lu@linux.intel.com> <20230727054837.147050-4-baolu.lu@linux.intel.com> From: Baolu Lu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2023/8/10 0:59, Jason Gunthorpe wrote: > On Thu, Jul 27, 2023 at 01:48:28PM +0800, Lu Baolu wrote: >> The unrecoverable fault data is not used anywhere. Remove it to avoid >> dead code. >> >> Suggested-by: Kevin Tian >> Signed-off-by: Lu Baolu >> --- >> include/linux/iommu.h | 70 +------------------------------------------ >> 1 file changed, 1 insertion(+), 69 deletions(-) > Do we plan to bring this back in some form? A driver specific fault > report via iommufd? I can hardly see the possibility. The only necessary dma fault messages are the offending address and the permissions. With these, the user space device model software knows that "a DMA fault was generated when the IOMMU hardware tried to translate the offending address with the given permissions". And then, the device model software will walk the page table and figure out what is missed before injecting the vendor-specific fault messages to the VM guest. Best regards, baolu