Commit e40f193f authored by Alex Williamson's avatar Alex Williamson Committed by Marcelo Tosatti
Browse files

KVM: Fix iommu map/unmap to handle memory slot moves 



The iommu integration into memory slots expects memory slots to be
added or removed and doesn't handle the move case.  We can unmap
slots from the iommu after we mark them invalid and map them before
installing the final memslot array.  Also re-order the kmemdup vs
map so we don't leave iommu mappings if we get ENOMEM.

Reviewed-by: default avatarGleb Natapov <gleb@redhat.com>
Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent 9c695d42

virt/kvm/kvm_main.c

+11 −8
Original line number Diff line number Diff line
@@ -822,6 +822,8 @@ int __kvm_set_memory_region(struct kvm *kvm, 
		old_memslots = kvm->memslots;

		rcu_assign_pointer(kvm->memslots, slots);

		synchronize_srcu_expedited(&kvm->srcu);

		/* slot was deleted or moved, clear iommu mapping */

		kvm_iommu_unmap_pages(kvm, &old);

		/* From this point no new shadow pages pointing to a deleted,

		 * or moved, memslot will be created.

		 *
@@ -837,20 +839,19 @@ int __kvm_set_memory_region(struct kvm *kvm, 
	if (r)

		goto out_free;



	/* map/unmap the pages in iommu page table */

	if (npages) {

		r = kvm_iommu_map_pages(kvm, &new);

		if (r)

			goto out_free;

	} else

		kvm_iommu_unmap_pages(kvm, &old);



	r = -ENOMEM;

	slots = kmemdup(kvm->memslots, sizeof(struct kvm_memslots),

			GFP_KERNEL);

	if (!slots)

		goto out_free;



	/* map new memory slot into the iommu */

	if (npages) {

		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 (!npages) {

		new.dirty_bitmap = NULL;
@@ -869,6 +870,8 @@ int __kvm_set_memory_region(struct kvm *kvm, 


	return 0;



out_slots:

	kfree(slots);

out_free:

	kvm_free_physmem_slot(&new, &old);

out:

CRA Git | Maintained and supported by SUSTech CRA and CCSE