From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756189Ab1E1SQ0 (ORCPT ); Sat, 28 May 2011 14:16:26 -0400 Received: from relay2.sgi.com ([192.48.179.30]:38235 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755312Ab1E1SPG (ORCPT ); Sat, 28 May 2011 14:15:06 -0400 Message-Id: <20110528181502.345585019@gulag1.americas.sgi.com> References: <20110528181501.896092225@gulag1.americas.sgi.com> User-Agent: quilt/0.46-1 Date: Sat, 28 May 2011 13:15:04 -0500 From: Mike Travis To: David Woodhouse , Chris Wright , Andrew Morton , Ingo Molnar Cc: Mike Habeck , Dimitri Sivanich , Derek Fults , Jesse Barnes , stable@kernel.org, iommu@lists.linux-foundation.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 3/7] Intel pci: Dont cache iova above 32bit Content-Disposition: inline; filename=dont-cache-iova-above-32bit.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. From: Chris Wright Reported-by: Mike Travis Reported-by: Mike Habeck Cc: David Woodhouse Cc: stable@kernel.org Acked-by: Mike Travis Tested-by: Mike Habeck Signed-off-by: Chris Wright --- v3: rb_next() can return NULL, found when testing on my hw David, Mike Travis will collect and resumbit full series when he's back. drivers/pci/iova.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) --- linux.orig/drivers/pci/iova.c +++ linux/drivers/pci/iova.c @@ -63,8 +63,16 @@ __cached_rbnode_delete_update(struct iov 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 (node && iova->pfn_lo < iovad->dma_32bit_pfn) + iovad->cached32_node = node; + else + iovad->cached32_node = NULL; + } } /* Computes the padding size required, to make the --