From patchwork Wed Dec 27 02:59:23 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ethan Zhao X-Patchwork-Id: 13505097 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.12]) (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 A891B3C2C; Wed, 27 Dec 2023 02:59:48 +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="jsYNCPOh" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1703645989; x=1735181989; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=ADwcXlRKPSNfjDAnN/YVM4hrSWE49DUML8+gC/Dr3BI=; b=jsYNCPOhi/jUGCF0keJYJC7op0yQ9JrfpIdppxFjs+u24JvJuGcEnocr kJIRDSxu1gE+DBMYKY+2KEs3n1G5155SKm01pxoNRDsnNj8TCXa4aak+6 eMk9WQee5MBpXYC0Dl8pfkcQktdlaHFmv3wHpk7wJBRIa6E6jqmIZlQ+P 7WzXNpvnIWhil4n5bxdM2GMC/CXKJPjY+VhelmjAwUD0lsfOUTU1aQyCo dFDJmq+0q6288KlDJwvi9liLWG9dr/+LnKSHLyKkhXvR9nzDe+76JLGJ/ 9MLeY+hGEHnvgOYjUQCuN6NjUT2kBLjqEDoTjVGYV8DVDWnL1dY1efFuZ A==; X-IronPort-AV: E=McAfee;i="6600,9927,10935"; a="3705836" X-IronPort-AV: E=Sophos;i="6.04,307,1695711600"; d="scan'208";a="3705836" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orvoesa104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Dec 2023 18:59:43 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10935"; a="951386103" X-IronPort-AV: E=Sophos;i="6.04,307,1695711600"; d="scan'208";a="951386103" Received: from ply01-vm-store.bj.intel.com ([10.238.153.201]) by orsmga005.jf.intel.com with ESMTP; 26 Dec 2023 18:59:40 -0800 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 Subject: [RFC PATCH v8 5/5] iommu/vt-d: don't loop for timeout device-TLB invalidation request forever Date: Tue, 26 Dec 2023 21:59:23 -0500 Message-Id: <20231227025923.536148-6-haifeng.zhao@linux.intel.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20231227025923.536148-1-haifeng.zhao@linux.intel.com> References: <20231227025923.536148-1-haifeng.zhao@linux.intel.com> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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 --- --- (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)