[PATCH 4/5] x86/amd-iommu: Fix deassignment of a device from the pt_domain

[Joerg Roedel <joerg.roedel@amd.com>]

Deassigning a device from the passthrough domain does not
work and breaks device assignment to kvm guests. This patch
fixes the issue.

Cc: stable@kernel.org
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/kernel/amd_iommu.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 751ce73..adb0ba0 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -1511,9 +1511,11 @@ static void __detach_device(struct device *dev)
 
 	/*
 	 * If we run in passthrough mode the device must be assigned to the
-	 * passthrough domain if it is detached from any other domain
+	 * passthrough domain if it is detached from any other domain.
+	 * Make sure we can deassign from the pt_domain itself.
 	 */
-	if (iommu_pass_through && dev_data->domain == NULL)
+	if (iommu_pass_through &&
+	    (dev_data->domain == NULL && domain != pt_domain))
 		__attach_device(dev, pt_domain);
 }
 
-- 
1.6.6