Commit c5b15255 authored by Sheng Yang's avatar Sheng Yang Committed by David Woodhouse

intel-iommu: Fix enabling snooping feature by mistake

Two defects work together result in KVM device passthrough randomly can't
work:
1. iommu_snooping is not initialized to zero when vm_iommu_init() called.
So it is possible to get a random value.
2. One line added by commit 2c2e2c38("IOMMU Identity Mapping Support")
change the code path, let it bypass domain_update_iommu_cap(), as well as
missing the increment of domain iommu reference count.

The latter is also likely to cause a leak of domains on repeated VMM 
assignment and deassignment.
Signed-off-by: default avatarSheng Yang <sheng@linux.intel.com>
Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent 33041ec0
......@@ -1505,7 +1505,6 @@ static int domain_context_mapping_one(struct dmar_domain *domain, int segment,
}
set_bit(num, iommu->domain_ids);
set_bit(iommu->seq_id, &domain->iommu_bmp);
iommu->domains[num] = domain;
id = num;
}
......@@ -3409,6 +3408,7 @@ static int md_domain_init(struct dmar_domain *domain, int guest_width)
domain->iommu_count = 0;
domain->iommu_coherency = 0;
domain->iommu_snooping = 0;
domain->max_addr = 0;
/* always allocate the top pgd */
......
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