From: Joerg Roedel <jroe...@suse.de>

When assigning devices to large memory guests (>=128GB guest
memory in the failure case) the functions to create the
IOMMU page-tables for the whole guest might run for a very
long time. On non-preemptible kernels this might cause
Soft-Lockup warnings. Fix these by adding a cond_resched()
to the mapping and unmapping loops.

Signed-off-by: Joerg Roedel <jroe...@suse.de>
---
 virt/kvm/iommu.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/virt/kvm/iommu.c b/virt/kvm/iommu.c
index c1e6ae9..ac427e8 100644
--- a/virt/kvm/iommu.c
+++ b/virt/kvm/iommu.c
@@ -137,7 +137,7 @@ int kvm_iommu_map_pages(struct kvm *kvm, struct 
kvm_memory_slot *slot)
 
                gfn += page_size >> PAGE_SHIFT;
 
-
+               cond_resched();
        }
 
        return 0;
@@ -311,6 +311,8 @@ static void kvm_iommu_put_pages(struct kvm *kvm,
                kvm_unpin_pages(kvm, pfn, unmap_pages);
 
                gfn += unmap_pages;
+
+               cond_resched();
        }
 }
 
-- 
1.9.1

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