amd-iommu: detach device explicitly before attaching it to a new domain

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

[chrisw: simply remove WARN_ON(), will always fire since dev->driver
will be pci-sub]

Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 81872604eb76..772e91088e40 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -2073,7 +2073,7 @@ 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);