Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756573Ab1DBAdU (ORCPT ); Fri, 1 Apr 2011 20:33:20 -0400 Received: from sous-sol.org ([216.99.217.87]:54070 "EHLO sequoia.sous-sol.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756237Ab1DBAdP (ORCPT ); Fri, 1 Apr 2011 20:33:15 -0400 Date: Fri, 1 Apr 2011 17:32:53 -0700 From: Chris Wright To: Mike Travis , Mike Habeck Cc: David Woodhouse , Chris Wright , Jesse Barnes , iommu@lists.linux-foundation.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 3/4 v2] intel-iommu: don't cache iova above 32bit caching boundary Message-ID: <20110402003253.GQ18712@sequoia.sous-sol.org> References: <20110329233602.272459647@gulag1.americas.sgi.com> <20110329233602.735667875@gulag1.americas.sgi.com> <4D94FC21.6040601@sgi.com> <20110331225316.GC18712@sequoia.sous-sol.org> <4D950D52.8080100@sgi.com> <4D951109.1040707@sgi.com> <20110331235657.GG18712@sequoia.sous-sol.org> <4D9524DF.10405@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4D9524DF.10405@sgi.com> User-Agent: Mutt/1.5.20 (2009-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2457 Lines: 61 Mike Travis and Mike Habeck reported an issue where iova allocation would return a range that was larger than a device's dma mask. https://lkml.org/lkml/2011/3/29/423 The dmar initialization code will reserve all PCI MMIO regions and copy those reservations into a domain specific iova tree. It is possible for one of those regions to be above the dma mask of a device. It is typical to allocate iovas with a 32bit mask (despite device's dma mask possibly being larger) and cache the result until it exhausts the lower 32bit address space. Freeing the iova range that is >= the last iova in the lower 32bit range when there is still an iova above the 32bit range will corrupt the cached iova by pointing it to a region that is above 32bit. If that region is also larger than the device's dma mask, a subsequent allocation will return an unusable iova and cause dma failure. Simply don't cache an iova that is above the 32bit caching boundary. Reported-by: Mike Travis Reported-by: Mike Habeck Cc: David Woodhouse Cc: stable@kernel.org Signed-off-by: Chris Wright --- Mike or Mike, can you try this? I was able to reproduce the failure in a few different ways and successfully test this patch against those failures, but w/out real hw. drivers/pci/iova.c | 12 ++++++++++-- 1 files changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/pci/iova.c b/drivers/pci/iova.c index 7914951..1690ca4 100644 --- a/drivers/pci/iova.c +++ b/drivers/pci/iova.c @@ -63,8 +63,16 @@ __cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free) curr = iovad->cached32_node; cached_iova = container_of(curr, struct iova, node); - if (free->pfn_lo >= cached_iova->pfn_lo) - iovad->cached32_node = rb_next(&free->node); + if (free->pfn_lo >= cached_iova->pfn_lo) { + struct rb_node *node = rb_next(&free->node); + struct iova *iova = container_of(node, struct iova, node); + + /* only cache if it's below 32bit pfn */ + if (iova->pfn_lo < iovad->dma_32bit_pfn) + iovad->cached32_node = node; + else + iovad->cached32_node = NULL; + } } /* Computes the padding size required, to make the -- 1.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/