From: Jiang Liu Date: Mon, 6 Jan 2014 06:18:08 +0000 (+0800) Subject: iommu/vt-d: use dedicated bitmap to track remapping entry allocation status X-Git-Tag: v3.14-rc1~50^2^3~18 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=360eb3c5687e;p=pandora-kernel.git iommu/vt-d: use dedicated bitmap to track remapping entry allocation status Currently Intel interrupt remapping drivers uses the "present" flag bit in remapping entry to track whether an entry is allocated or not. It works as follow: 1) allocate a remapping entry and set its "present" flag bit to 1 2) compose other fields for the entry 3) update the remapping entry with the composed value The remapping hardware may access the entry between step 1 and step 3, which then observers an entry with the "present" flag set but random values in all other fields. This patch introduces a dedicated bitmap to track remapping entry allocation status instead of sharing the "present" flag with hardware, thus eliminate the race window. It also simplifies the implementation. Tested-and-reviewed-by: Yijing Wang Signed-off-by: Jiang Liu Signed-off-by: Joerg Roedel --- Reading git-diff-tree failed