kvm/vfio: Support for DMA coherent IOMMUs (9d830d47) · Commits · 戴 / test

virt/kvm/vfio.c

+20 −7

Original line number	Diff line number	Diff line
		@@ -59,6 +59,22 @@ static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group)
		symbol_put(vfio_group_put_external_user);
		}

		static bool kvm_vfio_group_is_coherent(struct vfio_group *vfio_group)
		{
		long (fn)(struct vfio_group , unsigned long);
		long ret;

		fn = symbol_get(vfio_external_check_extension);
		if (!fn)
		return false;

		ret = fn(vfio_group, VFIO_DMA_CC_IOMMU);

		symbol_put(vfio_external_check_extension);

		return ret > 0;
		}

		/*
		* Groups can use the same or different IOMMU domains. If the same then
		* adding a new group may change the coherency of groups we've previously
		@@ -75,14 +91,11 @@ static void kvm_vfio_update_coherency(struct kvm_device *dev)
		mutex_lock(&kv->lock);

		list_for_each_entry(kvg, &kv->group_list, node) {
		/*
		* TODO: We need an interface to check the coherency of
		* the IOMMU domain this group is using. For now, assume
		* it's always noncoherent.
		*/
		if (!kvm_vfio_group_is_coherent(kvg->vfio_group)) {
		noncoherent = true;
		break;
		}
		}

		if (noncoherent != kv->noncoherent) {
		kv->noncoherent = noncoherent;