From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.31]) (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 53E45DDA9; Wed, 10 Jan 2024 05:33:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="Z6Nic5D3" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1704864833; x=1736400833; h=message-id:date:mime-version:cc:subject:to:references: from:in-reply-to:content-transfer-encoding; bh=YGke+ibjmKZatt4nYaBojbGAiAATE/h9fTo0wo5i5ew=; b=Z6Nic5D3NxleHGoLTktT6gxn4l9nJtqcb/1zA+y7fW14xqt/wsnNpaaT H7g8xPk3PZQMYoihcTRYaSd65+QtHzY+HkFk8A79AKJuFHiVtQZgGnu21 hqsqiXd7GboyiVa0nN5CArQEAWbyb+2LN0ayL1O+XunDcmaPmbhDTci2h Q6mOmK62gHNyNbzAn6yKGAf7XnynTVqf1cTgwiue54C0QVW3OAIAfv/7s 8J+ZPhY3sMnLKlpb3El7S0HkSQwaH6HS7nZGtNiM+KDsaAFzS8OkoMRc3 j6+55shce60g6r3aFu+el5A3XBzkfMkaH2DZdVZxjOYWGpXHzPpE/qEkI g==; X-IronPort-AV: E=McAfee;i="6600,9927,10947"; a="462698659" X-IronPort-AV: E=Sophos;i="6.04,184,1695711600"; d="scan'208";a="462698659" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Jan 2024 21:33:53 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10947"; a="1113321247" X-IronPort-AV: E=Sophos;i="6.04,184,1695711600"; d="scan'208";a="1113321247" Received: from allen-box.sh.intel.com (HELO [10.239.159.127]) ([10.239.159.127]) by fmsmga005.fm.intel.com with ESMTP; 09 Jan 2024 21:33:50 -0800 Message-ID: Date: Wed, 10 Jan 2024 13:28:36 +0800 Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: baolu.lu@linux.intel.com, linux-pci@vger.kernel.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH v10 5/5] iommu/vt-d: don't loop for timeout ATS Invalidation request forever Content-Language: en-US To: Ethan Zhao , kevin.tian@intel.com, bhelgaas@google.com, dwmw2@infradead.org, will@kernel.org, robin.murphy@arm.com, lukas@wunner.de References: <20231228170504.720794-1-haifeng.zhao@linux.intel.com> <20231228170504.720794-3-haifeng.zhao@linux.intel.com> From: Baolu Lu In-Reply-To: <20231228170504.720794-3-haifeng.zhao@linux.intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 12/29/23 1:05 AM, Ethan Zhao wrote: > When the ATS Invalidation request timeout happens, the qi_submit_sync() > will restart and loop for the invalidation request forever till it is > done, it will block another Invalidation thread such as the fq_timer > to issue invalidation request, cause the system lockup as following > > [exception RIP: native_queued_spin_lock_slowpath+92] > > RIP: ffffffffa9d1025c RSP: ffffb202f268cdc8 RFLAGS: 00000002 > > RAX: 0000000000000101 RBX: ffffffffab36c2a0 RCX: 0000000000000000 > > RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffab36c2a0 > > RBP: ffffffffab36c2a0 R8: 0000000000000001 R9: 0000000000000000 > > R10: 0000000000000010 R11: 0000000000000018 R12: 0000000000000000 > > R13: 0000000000000004 R14: ffff9e10d71b1c88 R15: ffff9e10d71b1980 > > ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 > > (the left part of exception see the hotplug case of ATS capable device) > > If one endpoint device just no response to the ATS Invalidation request, > but is not gone, it will bring down the whole system, to avoid such > case, don't try the timeout ATS Invalidation request forever. > > Signed-off-by: Ethan Zhao > --- > drivers/iommu/intel/dmar.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c > index 0a8d628a42ee..9edb4b44afca 100644 > --- a/drivers/iommu/intel/dmar.c > +++ b/drivers/iommu/intel/dmar.c > @@ -1453,7 +1453,7 @@ int qi_submit_sync(struct intel_iommu *iommu, struct qi_desc *desc, > reclaim_free_desc(qi); > raw_spin_unlock_irqrestore(&qi->q_lock, flags); > > - if (rc == -EAGAIN) > + if (rc == -EAGAIN && type !=QI_DIOTLB_TYPE && type != QI_DEIOTLB_TYPE) > goto restart; > > if (iotlb_start_ktime) Above is also unnecessary if qi_check_fault() returns -ETIMEDOUT, instead of -EAGAIN. Or did I miss anything? Best regards, baolu