[RFC 08/18] vfio/container: Introduce vfio_[attach/detach]_device

Yi Liu
2022-04-14T10:47:35Z

From: Eric Auger <eric.auger@redhat.com>

We want the VFIO devices to be able to use two different
IOMMU callbacks, the legacy VFIO one and the new iommufd one.

Introduce vfio_[attach/detach]_device which aim at hiding the
underlying IOMMU backend (IOCTLs, datatypes, ...).

Once vfio_attach_device completes, the device is attached
to a security context and its fd can be used. Conversely
When vfio_detach_device completes, the device has been
detached to the security context.

In this patch, only the vfio-pci device gets converted to use
the new API. Subsequent patches will handle other devices.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
hw/vfio/container.c | 65 +++++++++++++++++++++++++++++++++++
hw/vfio/pci.c | 50 +++------------------------
include/hw/vfio/vfio-common.h | 2 ++
3 files changed, 72 insertions(+), 45 deletions(-)

diff --git a/hw/vfio/container.c b/hw/vfio/container.c
index 79972064d3..c74a3cd4ae 100644
--- a/hw/vfio/container.c
+++ b/hw/vfio/container.c
@@ -1214,6 +1214,71 @@ int vfio_eeh_as_op(AddressSpace *as, uint32_t op)
return vfio_eeh_container_op(container, op);
}

+static int vfio_device_groupid(VFIODevice *vbasedev, Error **errp)
+{
+ char *tmp, group_path[PATH_MAX], *group_name;
+ int ret, groupid;
+ ssize_t len;
+
+ tmp = g_strdup_printf("%s/iommu_group", vbasedev->sysfsdev);
+ len = readlink(tmp, group_path, sizeof(group_path));
+ g_free(tmp);
+
+ if (len <= 0 || len >= sizeof(group_path)) {
+ ret = len < 0 ? -errno : -ENAMETOOLONG;
+ error_setg_errno(errp, -ret, "no iommu_group found");
+ return ret;
+ }
+
+ group_path[len] = 0;
+
+ group_name = basename(group_path);
+ if (sscanf(group_name, "%d", &groupid) != 1) {
+ error_setg_errno(errp, errno, "failed to read %s", group_path);
+ return -errno;
+ }
+ return groupid;
+}
+
+int vfio_attach_device(VFIODevice *vbasedev, AddressSpace *as, Error **errp)
+{
+ int groupid = vfio_device_groupid(vbasedev, errp);
+ VFIODevice *vbasedev_iter;
+ VFIOGroup *group;
+ int ret;
+
+ if (groupid < 0) {
+ return groupid;
+ }
+
+ trace_vfio_realize(vbasedev->name, groupid);
+ group = vfio_get_group(groupid, as, errp);
+ if (!group) {
+ return -1;
+ }
+
+ QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
+ if (strcmp(vbasedev_iter->name, vbasedev->name) == 0) {
+ error_setg(errp, "device is already attached");
+ vfio_put_group(group);
+ return -1;
+ }
+ }
+ ret = vfio_get_device(group, vbasedev->name, vbasedev, errp);
+ if (ret) {
+ vfio_put_group(group);
+ return -1;
+ }
+
+ return 0;
+}
+
+void vfio_detach_device(VFIODevice *vbasedev)
+{
+ vfio_put_base_device(vbasedev);
+ vfio_put_group(vbasedev->group);
+}
+
static void vfio_legacy_container_class_init(ObjectClass *klass,
void *data)
{
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index a00a485e46..0363f81017 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -2654,10 +2654,9 @@ static void vfio_populate_device(VFIOPCIDevice *vdev, Error **errp)

static void vfio_put_device(VFIOPCIDevice *vdev)
{
- g_free(vdev->vbasedev.name);
g_free(vdev->msix);

- vfio_put_base_device(&vdev->vbasedev);
+ vfio_detach_device(&vdev->vbasedev);
}

static void vfio_err_notifier_handler(void *opaque)
@@ -2804,13 +2803,9 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
{
VFIOPCIDevice *vdev = VFIO_PCI(pdev);
VFIODevice *vbasedev = &vdev->vbasedev;
- VFIODevice *vbasedev_iter;
- VFIOGroup *group;
- char *tmp, *subsys, group_path[PATH_MAX], *group_name;
+ char *tmp, *subsys;
Error *err = NULL;
- ssize_t len;
struct stat st;
- int groupid;
int i, ret;
bool is_mdev;

@@ -2839,39 +2834,6 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
vbasedev->type = VFIO_DEVICE_TYPE_PCI;
vbasedev->dev = DEVICE(vdev);

- tmp = g_strdup_printf("%s/iommu_group", vbasedev->sysfsdev);
- len = readlink(tmp, group_path, sizeof(group_path));
- g_free(tmp);
-
- if (len <= 0 || len >= sizeof(group_path)) {
- error_setg_errno(errp, len < 0 ? errno : ENAMETOOLONG,
- "no iommu_group found");
- goto error;
- }
-
- group_path[len] = 0;
-
- group_name = basename(group_path);
- if (sscanf(group_name, "%d", &groupid) != 1) {
- error_setg_errno(errp, errno, "failed to read %s", group_path);
- goto error;
- }
-
- trace_vfio_realize(vbasedev->name, groupid);
-
- group = vfio_get_group(groupid, pci_device_iommu_address_space(pdev), errp);
- if (!group) {
- goto error;
- }
-
- QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
- if (strcmp(vbasedev_iter->name, vbasedev->name) == 0) {
- error_setg(errp, "device is already attached");
- vfio_put_group(group);
- goto error;
- }
- }
-
/*
* Mediated devices *might* operate compatibly with discarding of RAM, but
* we cannot know for certain, it depends on whether the mdev vendor driver
@@ -2889,13 +2851,12 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
if (vbasedev->ram_block_discard_allowed && !is_mdev) {
error_setg(errp, "x-balloon-allowed only potentially compatible "
"with mdev devices");
- vfio_put_group(group);
goto error;
}

- ret = vfio_get_device(group, vbasedev->name, vbasedev, errp);
+ ret = vfio_attach_device(vbasedev,
+ pci_device_iommu_address_space(pdev), errp);
if (ret) {
- vfio_put_group(group);
goto error;
}

@@ -3124,12 +3085,12 @@ out_teardown:
vfio_bars_exit(vdev);
error:
error_prepend(errp, VFIO_MSG_PREFIX, vbasedev->name);
+ vfio_detach_device(vbasedev);
}

static void vfio_instance_finalize(Object *obj)
{
VFIOPCIDevice *vdev = VFIO_PCI(obj);
- VFIOGroup *group = vdev->vbasedev.group;

vfio_display_finalize(vdev);
vfio_bars_finalize(vdev);
@@ -3143,7 +3104,6 @@ static void vfio_instance_finalize(Object *obj)
* g_free(vdev->igd_opregion);
*/
vfio_put_device(vdev);
- vfio_put_group(group);
}

static void vfio_exitfn(PCIDevice *pdev)
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index 02a6f36a9e..978b2c2f6e 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -180,6 +180,8 @@ VFIOGroup *vfio_get_group(int groupid, AddressSpace *as, Error **errp);
void vfio_put_group(VFIOGroup *group);
int vfio_get_device(VFIOGroup *group, const char *name,
VFIODevice *vbasedev, Error **errp);
+int vfio_attach_device(VFIODevice *vbasedev, AddressSpace *as, Error **errp);
+void vfio_detach_device(VFIODevice *vbasedev);

extern const MemoryRegionOps vfio_region_ops;
typedef QLIST_HEAD(VFIOGroupList, VFIOGroup) VFIOGroupList;
--
2.27.0