[PATCH 2/2] kvm: Obey read-only mappings in iommu

Alex Williamson
2013-01-24T22:04:09Z

We've been ignoring read-only mappings and programming everything
into the iommu as read-write. Fix this to only include the write
access flag when read-only is not set.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
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 4a340cb..72a130b 100644
--- a/virt/kvm/iommu.c
+++ b/virt/kvm/iommu.c
@@ -76,7 +76,9 @@ int kvm_iommu_map_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
gfn = slot->base_gfn;
end_gfn = gfn + slot->npages;

- flags = IOMMU_READ | IOMMU_WRITE;
+ flags = IOMMU_READ;
+ if (!(slot->flags & KVM_MEM_READONLY))
+ flags |= IOMMU_WRITE;
if (kvm->arch.iommu_flags & KVM_IOMMU_CACHE_COHERENCY)
flags |= IOMMU_CACHE;