Virtualization - May 2023 - [PATCH v2 0/2] iommu/virtio: Fixes

One fix reported by Akihiko, and another found while going over the
driver.

Jean-Philippe Brucker (2):
  iommu/virtio: Detach domain on endpoint release
  iommu/virtio: Return size mapped for a detached domain

 drivers/iommu/virtio-iommu.c | 57 ++++++++++++++++++++++++++----------
 1 file changed, 41 insertions(+), 16 deletions(-)

-- 
2.40.0

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: edcd69ab9a32 ("iommu: Add virtio-iommu driver")
Reported-by: Akihiko Odaki <akihiko.odaki at daynix.com>
Link: https://lore.kernel.org/all/15bf1b00-3aa0-973a-3a86-3fa5c4d41d2c at
daynix.com/
Signed-off-by: Jean-Philippe Brucker <jean-philippe at linaro.org>
Tested-by: Akihiko Odaki <akihiko.odaki at daynix.com>
---
v1: https://lore.kernel.org/linux-iommu/20230414150744.562456-1-jean-philippe at
linaro.org/
v2: fixed nr_endpoints count reported by Eric
---
 drivers/iommu/virtio-iommu.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
index 5b8fe9bfa9a5b..fd316a37d7562 100644
--- a/drivers/iommu/virtio-iommu.c
+++ b/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);
 }
-- 
2.40.0

When map() is called on a detached domain, the domain does not exist in
the device so we do not send a MAP request, but we do update the
internal mapping tree, to be replayed on the next attach. Since this
constitutes a successful iommu_map() call, return *mapped in this case
too.

Fixes: 7e62edd7a33a ("iommu/virtio: Add map/unmap_pages() callbacks
implementation")
Signed-off-by: Jean-Philippe Brucker <jean-philippe at linaro.org>
---
 drivers/iommu/virtio-iommu.c | 33 +++++++++++++++++----------------
 1 file changed, 17 insertions(+), 16 deletions(-)

diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
index fd316a37d7562..3551ed057774e 100644
--- a/drivers/iommu/virtio-iommu.c
+++ b/drivers/iommu/virtio-iommu.c
@@ -833,25 +833,26 @@ static int viommu_map_pages(struct iommu_domain *domain,
unsigned long iova,
 	if (ret)
 		return ret;
 
-	map = (struct virtio_iommu_req_map) {
-		.head.type	= VIRTIO_IOMMU_T_MAP,
-		.domain		= cpu_to_le32(vdomain->id),
-		.virt_start	= cpu_to_le64(iova),
-		.phys_start	= cpu_to_le64(paddr),
-		.virt_end	= cpu_to_le64(end),
-		.flags		= cpu_to_le32(flags),
-	};
+	if (vdomain->nr_endpoints) {
+		map = (struct virtio_iommu_req_map) {
+			.head.type	= VIRTIO_IOMMU_T_MAP,
+			.domain		= cpu_to_le32(vdomain->id),
+			.virt_start	= cpu_to_le64(iova),
+			.phys_start	= cpu_to_le64(paddr),
+			.virt_end	= cpu_to_le64(end),
+			.flags		= cpu_to_le32(flags),
+		};
 
-	if (!vdomain->nr_endpoints)
-		return 0;
-
-	ret = viommu_send_req_sync(vdomain->viommu, &map, sizeof(map));
-	if (ret)
-		viommu_del_mappings(vdomain, iova, end);
-	else if (mapped)
+		ret = viommu_send_req_sync(vdomain->viommu, &map, sizeof(map));
+		if (ret) {
+			viommu_del_mappings(vdomain, iova, end);
+			return ret;
+		}
+	}
+	if (mapped)
 		*mapped = size;
 
-	return ret;
+	return 0;
 }
 
 static size_t viommu_unmap_pages(struct iommu_domain *domain, unsigned long
iova,
-- 
2.40.0

On Mon, May 15, 2023 at 12:39:46PM +0100, Jean-Philippe Brucker
wrote:
> One fix reported by Akihiko, and another found while going over the
> driver.
> 
> Jean-Philippe Brucker (2):
>   iommu/virtio: Detach domain on endpoint release
>   iommu/virtio: Return size mapped for a detached domain
> 
>  drivers/iommu/virtio-iommu.c | 57 ++++++++++++++++++++++++++----------
>  1 file changed, 41 insertions(+), 16 deletions(-)
Applied, thanks.