From 71684406905f98f86a85e008b51f5c4c5d83af5a Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Wed, 4 Mar 2015 11:30:10 -0700 Subject: [PATCH] iommu/vt-d: Detach domain *only* from attached iommus Device domains never span IOMMU hardware units, which allows the domain ID space for each IOMMU to be an independent address space. Therefore we can have multiple, independent domains, each with the same domain->id, but attached to different hardware units. This is also why we need to do a heavy-weight search for VM domains since they can span multiple IOMMUs hardware units and we don't require a single global ID to use for all hardware units. Therefore, if we call iommu_detach_domain() across all active IOMMU hardware units for a non-VM domain, the result is that we clear domain IDs that are not associated with our domain, allowing them to be re-allocated and causing apparent coherency issues when the device cannot access IOVAs for the intended domain. This bug was introduced in commit fb170fb4c548 ("iommu/vt-d: Introduce helper functions to make code symmetric for readability"), but is significantly exacerbated by the more recent commit 62c22167dd70 ("iommu/vt-d: Fix dmar_domain leak in iommu_attach_device") which calls domain_exit() more frequently to resolve a domain leak. Fixes: fb170fb4c548 ("iommu/vt-d: Introduce helper functions to make code symmetric for readability") Signed-off-by: Alex Williamson Cc: Jiang Liu Cc: stable@vger.kernel.org # v3.17+ Signed-off-by: Joerg Roedel --- drivers/iommu/intel-iommu.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index ae4c1a854e57..a83c965410e0 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -1743,8 +1743,8 @@ static int domain_init(struct dmar_domain *domain, int guest_width) static void domain_exit(struct dmar_domain *domain) { struct dmar_drhd_unit *drhd; - struct intel_iommu *iommu; struct page *freelist = NULL; + int i; /* Domain 0 is reserved, so dont process it */ if (!domain) @@ -1764,8 +1764,8 @@ static void domain_exit(struct dmar_domain *domain) /* clear attached or cached domains */ rcu_read_lock(); - for_each_active_iommu(iommu, drhd) - iommu_detach_domain(domain, iommu); + for_each_set_bit(i, domain->iommu_bmp, g_num_of_iommus) + iommu_detach_domain(domain, g_iommus[i]); rcu_read_unlock(); dma_free_pagelist(freelist); -- 2.34.1