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

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Date:	Thu, 24 Jan 2013 15:04:09 -0700
From:	Alex Williamson <alex.williamson@...hat.com>
To:	gleb@...hat.com, kvm@...r.kernel.org
Cc:	yoshikawa_takuya_b1@....ntt.co.jp, linux-kernel@...r.kernel.org,
	xiaoguangrong@...ux.vnet.ibm.com
Subject: [PATCH 2/2] kvm: Obey read-only mappings in iommu

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@...hat.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;
 

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