[Patch Part3 V4 07/21] iommu/vt-d: Avoid freeing virtual machine domain in free_dmar_iommu()

Virtual machine domains are created by intel_iommu_domain_init() and
should be destroyed by intel_iommu_domain_destroy(). So avoid freeing
virtual machine domain data structure in free_dmar_iommu() when
doamin->iommu_count reaches zero, otherwise it may cause invalid
memory access because the IOMMU framework still holds references
to the domain structure.

Signed-off-by: Jiang Liu <[email protected]>
---
 drivers/iommu/intel-iommu.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 0984fa58d872..5d7383775bf1 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -1480,7 +1480,8 @@ static void free_dmar_iommu(struct intel_iommu *iommu)
 
 			domain = iommu->domains[i];
 			clear_bit(i, iommu->domain_ids);
-			if (domain_detach_iommu(domain, iommu) = 0)
+			if (domain_detach_iommu(domain, iommu) = 0 &&
+			    !domain_type_is_vm(domain))
 				domain_exit(domain);
 		}
 	}
-- 
1.7.10.4