iommu/virtio: Detach domain on endpoint release

When an endpoint is released, for example a PCIe VF being destroyed or a
function hot-unplugged, it should be detached from its domain. Send a
DETACH request.

Fixes: edcd69a ("iommu: Add virtio-iommu driver")
Reported-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Link: https://lore.kernel.org/all/15bf1b00-3aa0-973a-3a86-3fa5c4d41d2c@daynix.com/
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Tested-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Link: https://lore.kernel.org/r/20230515113946.1017624-2-jean-philippe@linaro.org
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Author: Jean-Philippe Brucker

drivers/iommu/virtio-iommu.c

@@ -788,6 +788,29 @@ static int viommu_attach_dev(struct iommu_domain *domain, struct device *dev)
 	return 0;
 }
 
+static void viommu_detach_dev(struct viommu_endpoint *vdev)
+{
+	int i;
+	struct virtio_iommu_req_detach req;
+	struct viommu_domain *vdomain = vdev->vdomain;
+	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(vdev->dev);
+
+	if (!vdomain)
+		return;
+
+	req = (struct virtio_iommu_req_detach) {
+		.head.type	= VIRTIO_IOMMU_T_DETACH,
+		.domain		= cpu_to_le32(vdomain->id),
+	};
+
+	for (i = 0; i < fwspec->num_ids; i++) {
+		req.endpoint = cpu_to_le32(fwspec->ids[i]);
+		WARN_ON(viommu_send_req_sync(vdev->viommu, &req, sizeof(req)));
+	}
+	vdomain->nr_endpoints--;
+	vdev->vdomain = NULL;
+}
+
 static int viommu_map_pages(struct iommu_domain *domain, unsigned long iova,
 			    phys_addr_t paddr, size_t pgsize, size_t pgcount,
 			    int prot, gfp_t gfp, size_t *mapped)
@@ -990,6 +1013,7 @@ static void viommu_release_device(struct device *dev)
 {
 	struct viommu_endpoint *vdev = dev_iommu_priv_get(dev);
 
+	viommu_detach_dev(vdev);
 	iommu_put_resv_regions(dev, &vdev->resv_regions);
 	kfree(vdev);
 }