From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: [PATCH 10/19] iommu/vt-d: Don't copy translation tables if RTT bit needs to be changed Date: Sat, 13 Jun 2015 08:47:18 +0200 Message-ID: <1434178047-17809-11-git-send-email-joro@8bytes.org> References: <1434178047-17809-1-git-send-email-joro@8bytes.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1434178047-17809-1-git-send-email-joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Cc: Joerg Roedel , David Woodhouse , jroedel-zLv9SwRftAIdnm+yROfE0A@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, zhen-hual-VXdhtT5mjnY@public.gmane.org, dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org List-Id: iommu@lists.linux-foundation.org From: Joerg Roedel We can't change the RTT bit when translation is enabled, so don't copy translation tables when we would change the bit with our new root entry. Signed-off-by: Joerg Roedel --- drivers/iommu/intel-iommu.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 39bc3d6..e23d5b4 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -2914,10 +2914,20 @@ static int copy_translation_tables(struct intel_iommu *iommu) unsigned long flags; u64 rtaddr_reg; int bus, ret; - bool ext; + bool new_ext, ext; rtaddr_reg = dmar_readq(iommu->reg + DMAR_RTADDR_REG); ext = !!(rtaddr_reg & DMA_RTADDR_RTT); + new_ext = !!ecap_ecs(iommu->ecap); + + /* + * The RTT bit can only be changed when translation is disabled, + * but disabling translation means to open a window for data + * corruption. So bail out and don't copy anything if we would + * have to change the bit. + */ + if (new_ext != ext) + return -EINVAL; old_rt_phys = rtaddr_reg & VTD_PAGE_MASK; if (!old_rt_phys) -- 1.9.1