From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.9]) (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 B181F23A6; Wed, 27 Dec 2023 03:03:19 +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="LgT7qPFn" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1703646200; x=1735182200; h=message-id:date:mime-version:subject:from:to:cc: references:in-reply-to:content-transfer-encoding; bh=ku0cvgjSyljgDuQ59NAwnQl5wGFzA78P+anngskXiPQ=; b=LgT7qPFnb5uLxfHCu1DtIWMfkC+pkazsaJla/keYOIOCNsYxgtiZLHCq bZajv0fkFLzS1ATqk6J76TFdWfI+j7/M5HBcB0dBML06Y0+AG5thM5vaf /VWFBdFnNuVkoE7Tn8g97teI6lKcw/RgaxS3euQYtpyZvHUWSDfdIhXWI 9UyzczKxy+saSsIDS4oGSCF0+2mmS8XBBgcukUxqbOKH//y6R5L/ZDLWn iqFp9fALhmEsoVM+neuQbeZsQC0qLVoCF0xiKuTDkdkjAwhZqJlxAowPC pKMcc01YB780jtPnh7WBOXprLJOCSxkh+dOtAYlO5teckR1PfLXkxJtgB g==; X-IronPort-AV: E=McAfee;i="6600,9927,10935"; a="15076684" X-IronPort-AV: E=Sophos;i="6.04,307,1695711600"; d="scan'208";a="15076684" Received: from fmviesa001.fm.intel.com ([10.60.135.141]) by orvoesa101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Dec 2023 19:03:20 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.04,307,1695711600"; d="scan'208";a="20177524" Received: from zhaohaif-mobl.ccr.corp.intel.com (HELO [10.255.28.66]) ([10.255.28.66]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Dec 2023 19:03:16 -0800 Message-ID: <85c96e7d-de2d-46a8-b1d6-f970312b4449@linux.intel.com> Date: Wed, 27 Dec 2023 11:03:13 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v8 5/5] iommu/vt-d: don't loop for timeout device-TLB invalidation request forever From: Ethan Zhao To: bhelgaas@google.com, baolu.lu@linux.intel.com, dwmw2@infradead.org, will@kernel.org, robin.murphy@arm.com, lukas@wunner.de Cc: linux-pci@vger.kernel.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org References: <20231227025923.536148-1-haifeng.zhao@linux.intel.com> <20231227025923.536148-6-haifeng.zhao@linux.intel.com> In-Reply-To: <20231227025923.536148-6-haifeng.zhao@linux.intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 12/27/2023 10:59 AM, Ethan Zhao wrote: > When the device-TLB invalidation (ATS invalidation) 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 --- --- #12 [ffffb202f268cdc8] native_queued_spin_lock_slowpath at ffffffffa9d1025c #13 [ffffb202f268cdc8] do_raw_spin_lock at ffffffffa9d121f1 #14 [ffffb202f268cdd8] _raw_spin_lock_irqsave at ffffffffaa51795b #15 [ffffb202f268cdf8] iommu_flush_dev_iotlb at ffffffffaa20df48 #16 [ffffb202f268ce28] iommu_flush_iova at ffffffffaa20e182 #17 [ffffb202f268ce60] iova_domain_flush at ffffffffaa220e27 #18 [ffffb202f268ce70] fq_flush_timeout at ffffffffaa221c9d #19 [ffffb202f268cea8] call_timer_fn at ffffffffa9d46661 #20 [ffffb202f268cf08] run_timer_softirq at ffffffffa9d47933 #21 [ffffb202f268cf98] __softirqentry_text_start at ffffffffaa8000e0 #22 [ffffb202f268cff0] asm_call_sysvec_on_stack at ffffffffaa60114f > --- --- > > (the left part of exception see the hotplug case of ATS capable device) > > If one endpoint device just no response to the device-TLB invalidation > request, but is not gone, it will bring down the whole system, to avoid > such case, don't try the timeout device-TLB request forever. > > and as synchronous program model of current qi_submit_sync() implementation > we couldn't wait for the enough time as PCIe spec said 1min+50%, just break > it in current sync model. (PCIe spec r6.1, sec 10.3.1) > > 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 76903a8bf963..206ab0b7294f 100644 > --- a/drivers/iommu/intel/dmar.c > +++ b/drivers/iommu/intel/dmar.c > @@ -1457,7 +1457,7 @@ 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)