From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.115]) (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 8EAF27464; Wed, 27 Dec 2023 03:11:12 +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="Bih9EM+3" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1703646672; x=1735182672; h=message-id:date:mime-version:subject:from:to:cc: references:in-reply-to:content-transfer-encoding; bh=ic5p65YwJaFgI53HOX8SILyahR+vq0xdwAXMLhbWmHQ=; b=Bih9EM+3z11eBwZfamy9VZgct6XEHQmeU1fp/Zy0SFisiSKFtuRKIeV9 Pk+JMwtb9EWKxI1wFJScRFh0PpmNGVTGdvkr/qdUF7Waxq3Naw2kqIGa/ GAY3qLoS0l5zDe6EtAm/pKhqGKxn4Yur28m6/sNOGwAVIwUZoq0qvbHJJ VsGrgWFWzZNaMNoo5lohH6/ydsRANlTJAH4So+2dzgxL7/nuZUXm/l5of fF4FoBi3PD7uzI6Uj7VOGJg1OomcfRS7KREZvOjPbtM6iteDC9DStQr0R mC3Mnp1CZy7M4xXps06ZFu0QD7L+EVkeBj/8kXCRNLo+fwZQTw4jbIFh+ g==; X-IronPort-AV: E=McAfee;i="6600,9927,10935"; a="396135618" X-IronPort-AV: E=Sophos;i="6.04,307,1695711600"; d="scan'208";a="396135618" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Dec 2023 19:11:11 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10935"; a="1025280121" X-IronPort-AV: E=Sophos;i="6.04,307,1695711600"; d="scan'208";a="1025280121" Received: from zhaohaif-mobl.ccr.corp.intel.com (HELO [10.255.28.66]) ([10.255.28.66]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Dec 2023 19:11:08 -0800 Message-ID: Date: Wed, 27 Dec 2023 11:11:06 +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 Wrong past, please ignore this series. Thanks, Ethan > > --- --- > > (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)