[patch 19/71] KVM: take mmu_lock when updating a deleted slot

[Greg KH]

2.6.30-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Marcelo Tosatti <mtosatti@xxxxxxxxxx>

(cherry picked from commit b43b1901ad282aeb74161837fb403927102687a1)

kvm_handle_hva relies on mmu_lock protection to safely access
the memslot structures.

Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Signed-off-by: Avi Kivity <avi@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
 virt/kvm/kvm_main.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1055,8 +1055,10 @@ int __kvm_set_memory_region(struct kvm *
 
 	kvm_free_physmem_slot(&old, npages ? &new : NULL);
 	/* Slot deletion case: we have to update the current slot */
+	spin_lock(&kvm->mmu_lock);
 	if (!npages)
 		*memslot = old;
+	spin_unlock(&kvm->mmu_lock);
 #ifdef CONFIG_DMAR
 	/* map the pages in iommu page table */
 	r = kvm_iommu_map_pages(kvm, base_gfn, npages);


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