[72/93] x86/amd-iommu: Fix deassignment of a device from the pt_domain

2.6.32-stable review patch.  If anyone has any objections, please let us know.

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From: Joerg Roedel <joerg.roedel@amd.com>

commit d3ad9373b7c29b63d5e8460a69453718d200cc3b upstream.

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

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 arch/x86/kernel/amd_iommu.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -1230,9 +1230,10 @@ static void __detach_device(struct prote
 
 	/*
 	 * 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) {
+	if (iommu_pass_through && domain != pt_domain) {
 		struct amd_iommu *iommu = amd_iommu_rlookup_table[devid];
 		__attach_device(iommu, pt_domain, devid);
 	}