KVM: Mapping IOMMU pages after updating memslot
In kvm_iommu_map_pages(), we need to know the page size via call
kvm_host_page_size(). And it will check whether the target slot
is valid before return the right page size.
Currently, we will map the iommu pages when creating a new slot.
But we call kvm_iommu_map_pages() during preparing the new slot.
At that time, the new slot is not visible by domain(still in preparing).
So we cannot get the right page size from kvm_host_page_size() and
this will break the IOMMU super page logic.
The solution is to map the iommu pages after we insert the new slot
into domain.
Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Tested-by: Patrick Lu <patrick.lu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 0d20c32..9ca014d 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -873,21 +873,6 @@
goto out_free;
}
- /*
- * IOMMU mapping: New slots need to be mapped. Old slots need to be
- * un-mapped and re-mapped if their base changes. Since base change
- * unmapping is handled above with slot deletion, mapping alone is
- * needed here. Anything else the iommu might care about for existing
- * slots (size changes, userspace addr changes and read-only flag
- * changes) is disallowed above, so any other attribute changes getting
- * here can be skipped.
- */
- if ((change == KVM_MR_CREATE) || (change == KVM_MR_MOVE)) {
- r = kvm_iommu_map_pages(kvm, &new);
- if (r)
- goto out_slots;
- }
-
/* actual memory is freed via old in kvm_free_physmem_slot below */
if (change == KVM_MR_DELETE) {
new.dirty_bitmap = NULL;
@@ -901,6 +886,20 @@
kvm_free_physmem_slot(&old, &new);
kfree(old_memslots);
+ /*
+ * IOMMU mapping: New slots need to be mapped. Old slots need to be
+ * un-mapped and re-mapped if their base changes. Since base change
+ * unmapping is handled above with slot deletion, mapping alone is
+ * needed here. Anything else the iommu might care about for existing
+ * slots (size changes, userspace addr changes and read-only flag
+ * changes) is disallowed above, so any other attribute changes getting
+ * here can be skipped.
+ */
+ if ((change == KVM_MR_CREATE) || (change == KVM_MR_MOVE)) {
+ r = kvm_iommu_map_pages(kvm, &new);
+ return r;
+ }
+
return 0;
out_slots:
