From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933345AbcHNLUg (ORCPT ); Sun, 14 Aug 2016 07:20:36 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:51911 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932687AbcHNLAd (ORCPT ); Sun, 14 Aug 2016 07:00:33 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Alex Williamson" , "Joerg Roedel" Date: Sat, 13 Aug 2016 18:42:51 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 006/305] iommu/vt-d: Ratelimit fault handler In-Reply-To: X-SA-Exim-Connect-IP: 92.40.249.202 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.37-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Alex Williamson commit c43fce4eebae257ca413733690e2076757282093 upstream. Fault rates can easily overwhelm the console and make the system unresponsive. Ratelimit to allow an opportunity for maintenance. Signed-off-by: Alex Williamson Fixes: 0ac2491f57af ('x86, dmar: move page fault handling code to dmar.c') Signed-off-by: Joerg Roedel Signed-off-by: Ben Hutchings --- drivers/iommu/dmar.c | 33 ++++++++++++++++++++++----------- 1 file changed, 22 insertions(+), 11 deletions(-) --- a/drivers/iommu/dmar.c +++ b/drivers/iommu/dmar.c @@ -1482,10 +1482,17 @@ irqreturn_t dmar_fault(int irq, void *de int reg, fault_index; u32 fault_status; unsigned long flag; + bool ratelimited; + static DEFINE_RATELIMIT_STATE(rs, + DEFAULT_RATELIMIT_INTERVAL, + DEFAULT_RATELIMIT_BURST); + + /* Disable printing, simply clear the fault when ratelimited */ + ratelimited = !__ratelimit(&rs); raw_spin_lock_irqsave(&iommu->register_lock, flag); fault_status = readl(iommu->reg + DMAR_FSTS_REG); - if (fault_status) + if (fault_status && !ratelimited) pr_err("DRHD: handling fault status reg %x\n", fault_status); /* TBD: ignore advanced fault log currently */ @@ -1507,24 +1514,28 @@ irqreturn_t dmar_fault(int irq, void *de if (!(data & DMA_FRCD_F)) break; - fault_reason = dma_frcd_fault_reason(data); - type = dma_frcd_type(data); - - data = readl(iommu->reg + reg + - fault_index * PRIMARY_FAULT_REG_LEN + 8); - source_id = dma_frcd_source_id(data); + if (!ratelimited) { + fault_reason = dma_frcd_fault_reason(data); + type = dma_frcd_type(data); + + data = readl(iommu->reg + reg + + fault_index * PRIMARY_FAULT_REG_LEN + 8); + source_id = dma_frcd_source_id(data); + + guest_addr = dmar_readq(iommu->reg + reg + + fault_index * PRIMARY_FAULT_REG_LEN); + guest_addr = dma_frcd_page_addr(guest_addr); + } - guest_addr = dmar_readq(iommu->reg + reg + - fault_index * PRIMARY_FAULT_REG_LEN); - guest_addr = dma_frcd_page_addr(guest_addr); /* clear the fault */ writel(DMA_FRCD_F, iommu->reg + reg + fault_index * PRIMARY_FAULT_REG_LEN + 12); raw_spin_unlock_irqrestore(&iommu->register_lock, flag); - dmar_fault_do_one(iommu, type, fault_reason, - source_id, guest_addr); + if (!ratelimited) + dmar_fault_do_one(iommu, type, fault_reason, + source_id, guest_addr); fault_index++; if (fault_index >= cap_num_fault_regs(iommu->cap))