From: Bhavna Sarathy <bnagendr@redhat.com>
Date: Tue, 9 Jun 2009 09:38:27 -0400
Subject: [x86_64] kvm: fix libvirt based device assignment issue
Message-id: 20090609133259.11704.29974.sendpatchset@allegro.boston.redhat.com
O-Subject: [RHEL5.4 PATCH] [KVM] Fix libvirt based device assignment issue on AMD IOMMU
Bugzilla: 504165
RH-Acked-by: Dean Nelson <dnelson@redhat.com>
RH-Acked-by: Chris Wright <chrisw@redhat.com>
RH-Acked-by: Juan Quintela <quintela@redhat.com>

Resolves BZ 504165

This fixes a bug with device that could not be assigned to a KVM guest
because it was still assigned to a dma_ops protection module.

Brew build:
http://brewweb.devel.redhat.com/brew/taskinfo?taskID=1830208

Tested on AMD IOMMU system at AMD and by Chris Wright.

Please review and ACK

diff --git a/arch/x86_64/kernel/amd_iommu.c b/arch/x86_64/kernel/amd_iommu.c
index dab0ff5..5379f85 100644
--- a/arch/x86_64/kernel/amd_iommu.c
+++ b/arch/x86_64/kernel/amd_iommu.c
@@ -1841,7 +1841,7 @@ static int amd_iommu_attach_device(struct iommu_domain *dom,
 
 	old_domain = domain_for_device(devid);
 	if (old_domain)
-		return -EBUSY;
+		detach_device(old_domain, devid);
 
 	attach_device(iommu, domain, devid);