From f73a7eee900e95404b61408a23a1df5c5811704c Mon Sep 17 00:00:00 2001 From: KarimAllah Ahmed Date: Fri, 5 May 2017 11:39:59 -0700 Subject: [PATCH] iommu/vt-d: Flush the IOTLB to get rid of the initial kdump mappings Ever since commit 091d42e43d ("iommu/vt-d: Copy translation tables from old kernel") the kdump kernel copies the IOMMU context tables from the previous kernel. Each device mappings will be destroyed once the driver for the respective device takes over. This unfortunately breaks the workflow of mapping and unmapping a new context to the IOMMU. The mapping function assumes that either: 1) Unmapping did the proper IOMMU flushing and it only ever flush if the IOMMU unit supports caching invalid entries. 2) The system just booted and the initialization code took care of flushing all IOMMU caches. This assumption is not true for the kdump kernel since the context tables have been copied from the previous kernel and translations could have been cached ever since. So make sure to flush the IOTLB as well when we destroy these old copied mappings. Cc: Joerg Roedel Cc: David Woodhouse Cc: David Woodhouse Cc: Anthony Liguori Signed-off-by: KarimAllah Ahmed Acked-by: David Woodhouse Cc: stable@vger.kernel.org v4.2+ Fixes: 091d42e43d ("iommu/vt-d: Copy translation tables from old kernel") Signed-off-by: Joerg Roedel --- drivers/iommu/intel-iommu.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 90ab0115d78e..fc2765ccdb57 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -2055,11 +2055,14 @@ static int domain_context_mapping_one(struct dmar_domain *domain, if (context_copied(context)) { u16 did_old = context_domain_id(context); - if (did_old >= 0 && did_old < cap_ndoms(iommu->cap)) + if (did_old >= 0 && did_old < cap_ndoms(iommu->cap)) { iommu->flush.flush_context(iommu, did_old, (((u16)bus) << 8) | devfn, DMA_CCMD_MASK_NOBIT, DMA_CCMD_DEVICE_INVL); + iommu->flush.flush_iotlb(iommu, did_old, 0, 0, + DMA_TLB_DSI_FLUSH); + } } pgd = domain->pgd; -- 2.39.5