From c3361f2f6e1d64bc7e7b8148bbd1c66b8007a898 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Fri, 12 Jun 2015 12:39:25 +0200 Subject: [PATCH] iommu/vt-d: Don't copy translation tables if RTT bit needs to be changed 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. Tested-by: ZhenHua Li Tested-by: Baoquan He 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 3b32aa55f27c..ca7d37c3981f 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -2934,10 +2934,20 @@ 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)