From owner-svn-src-stable@freebsd.org Wed Nov 2 08:41:03 2016 Return-Path: Delivered-To: svn-src-stable@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 4F23DC29552; Wed, 2 Nov 2016 08:41:03 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 11C9E1230; Wed, 2 Nov 2016 08:41:02 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id uA28f2U4006161; Wed, 2 Nov 2016 08:41:02 GMT (envelope-from kib@FreeBSD.org) Received: (from kib@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id uA28f2Xf006160; Wed, 2 Nov 2016 08:41:02 GMT (envelope-from kib@FreeBSD.org) Message-Id: <201611020841.uA28f2Xf006160@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: kib set sender to kib@FreeBSD.org using -f From: Konstantin Belousov Date: Wed, 2 Nov 2016 08:41:02 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r308207 - stable/11/sys/dev/e1000 X-SVN-Group: stable-11 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-stable@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: SVN commit messages for all the -stable branches of the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 02 Nov 2016 08:41:03 -0000 Author: kib Date: Wed Nov 2 08:41:01 2016 New Revision: 308207 URL: https://svnweb.freebsd.org/changeset/base/308207 Log: MFC r307649: Partial workaround for Intel PCI adapters reading past the end of the host-programmed DMA regions. Modified: stable/11/sys/dev/e1000/if_lem.c Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/dev/e1000/if_lem.c ============================================================================== --- stable/11/sys/dev/e1000/if_lem.c Wed Nov 2 08:12:37 2016 (r308206) +++ stable/11/sys/dev/e1000/if_lem.c Wed Nov 2 08:41:01 2016 (r308207) @@ -591,8 +591,16 @@ lem_attach(device_t dev) } #endif /* NIC_PARAVIRT */ - tsize = roundup2(adapter->num_tx_desc * sizeof(struct e1000_tx_desc), - EM_DBA_ALIGN); + /* + * It seems that the descriptor DMA engine on some PCI cards + * fetches memory past the end of the last descriptor in the + * ring. These reads are problematic when VT-d (DMAR) busdma + * is used. Allocate the scratch space to avoid getting + * faults from DMAR, by requesting scratch memory for one more + * descriptor. + */ + tsize = roundup2((adapter->num_tx_desc + 1) * + sizeof(struct e1000_tx_desc), EM_DBA_ALIGN); /* Allocate Transmit Descriptor ring */ if (lem_dma_malloc(adapter, tsize, &adapter->txdma, BUS_DMA_NOWAIT)) { @@ -603,8 +611,11 @@ lem_attach(device_t dev) adapter->tx_desc_base = (struct e1000_tx_desc *)adapter->txdma.dma_vaddr; - rsize = roundup2(adapter->num_rx_desc * sizeof(struct e1000_rx_desc), - EM_DBA_ALIGN); + /* + * See comment above txdma allocation for rationale behind +1. + */ + rsize = roundup2((adapter->num_rx_desc + 1) * + sizeof(struct e1000_rx_desc), EM_DBA_ALIGN); /* Allocate Receive Descriptor ring */ if (lem_dma_malloc(adapter, rsize, &adapter->rxdma, BUS_DMA_NOWAIT)) {