Add an API to support getting VFIOGroup from groupfd. When
groupfd is shared by another process, the VFIOGroup may not
have its container and address space in QEMU.
Besides, add a reference counter to better support getting
VFIOGroup multiple times.
Signed-off-by: Tiwei Bie <tiwei....@intel.com>
---
hw/vfio/common.c | 96 ++++++++++++++++++++++++++++++++++++++++++-
include/hw/vfio/vfio-common.h | 2 +
2 files changed, 97 insertions(+), 1 deletion(-)
diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 7b2924c0ef..027fa005c1 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -962,6 +962,11 @@ static int vfio_connect_container(VFIOGroup *group,
AddressSpace *as,
int ret, fd;
VFIOAddressSpace *space;
+ if (as == NULL) {
+ vfio_kvm_device_add_group(group);
+ return 0;
+ }
+
space = vfio_get_address_space(as);
QLIST_FOREACH(container, &space->containers, next) {
@@ -1153,6 +1158,10 @@ static void vfio_disconnect_container(VFIOGroup *group)
{
VFIOContainer *container = group->container;
+ if (container == NULL) {
+ return;
+ }
+
if (ioctl(group->fd, VFIO_GROUP_UNSET_CONTAINER, &container->fd)) {
error_report("vfio: error disconnecting group %d from container",
group->groupid);
@@ -1183,6 +1192,85 @@ static void vfio_disconnect_container(VFIOGroup *group)
}
}
+static int vfio_groupfd_to_groupid(int groupfd)
+{
+ char linkname[PATH_MAX];
+ char pathname[PATH_MAX];
+ char *filename;
+ int groupid, ret;
+
+ snprintf(linkname, sizeof(linkname), "/proc/self/fd/%d", groupfd);
+
+ ret = readlink(linkname, pathname, sizeof(pathname));
+ if (ret < 0) {
+ return -1;
+ }
+
+ filename = g_path_get_basename(pathname);
+ groupid = atoi(filename);
+ g_free(filename);
+
+ return groupid;
+}
+
+/*
+ * The @as param could be NULL. In this case, groupfd is shared by
+ * another process which will setup the DMA mapping for this group,
+ * and this group won't have container and address space in QEMU.
+ */
+VFIOGroup *vfio_get_group_from_fd(int groupfd, AddressSpace *as, Error **errp)
+{
+ VFIOGroup *group;
+ int groupid;
+
+ groupid = vfio_groupfd_to_groupid(groupfd);
+ if (groupid < 0) {
+ return NULL;
+ }
+
+ QLIST_FOREACH(group, &vfio_group_list, next) {
+ if (group->groupid == groupid) {
+ /* Found it. Now is it already in the right context? */
+ if ((group->container == NULL && as == NULL) ||
+ (group->container && group->container->space->as == as)) {
+ group->refcnt++;
+ return group;
+ }
+ error_setg(errp, "group %d used in multiple address spaces",
+ group->groupid);
+ return NULL;
+ }
+ }
+
+ group = g_malloc0(sizeof(*group));
+
+ group->fd = groupfd;
+ group->groupid = groupid;
+ group->refcnt = 1;
+
+ QLIST_INIT(&group->device_list);
+
+ if (vfio_connect_container(group, as, errp)) {
+ error_prepend(errp, "failed to setup container for group %d: ",
+ groupid);
+ goto free_group_exit;
+ }
+
+ if (QLIST_EMPTY(&vfio_group_list)) {
+ qemu_register_reset(vfio_reset_handler, NULL);
+ }
+
+ QLIST_INSERT_HEAD(&vfio_group_list, group, next);
+
+ return group;
+
+free_group_exit:
+ g_free(group);
+
+ return NULL;
+}
+
+/* The @as param cannot be NULL. */
VFIOGroup *vfio_get_group(int groupid, AddressSpace *as, Error **errp)
{
VFIOGroup *group;
@@ -1192,7 +1280,8 @@ VFIOGroup *vfio_get_group(int groupid, AddressSpace *as,
Error **errp)
QLIST_FOREACH(group, &vfio_group_list, next) {
if (group->groupid == groupid) {
/* Found it. Now is it already in the right context? */
- if (group->container->space->as == as) {
+ if (group->container && group->container->space->as == as) {
+ group->refcnt++;
return group;
} else {
error_setg(errp, "group %d used in multiple address spaces",
@@ -1225,6 +1314,7 @@ VFIOGroup *vfio_get_group(int groupid, AddressSpace *as,
Error **errp)
}
group->groupid = groupid;
+ group->refcnt = 1;
QLIST_INIT(&group->device_list);
if (vfio_connect_container(group, as, errp)) {
@@ -1256,6 +1346,10 @@ void vfio_put_group(VFIOGroup *group)
return;
}
+ if (--group->refcnt > 0) {
+ return;
+ }
+
vfio_kvm_device_del_group(group);
vfio_disconnect_container(group);
QLIST_REMOVE(group, next);
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index f3a2ac9fee..2383ded670 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -136,6 +136,7 @@ struct VFIODeviceOps {
typedef struct VFIOGroup {
int fd;
int groupid;
+ int refcnt;
VFIOContainer *container;
QLIST_HEAD(, VFIODevice) device_list;
QLIST_ENTRY(VFIOGroup) next;
@@ -158,6 +159,7 @@ void vfio_region_exit(VFIORegion *region);
void vfio_region_finalize(VFIORegion *region);
void vfio_reset_handler(void *opaque);
VFIOGroup *vfio_get_group(int groupid, AddressSpace *as, Error **errp);
+VFIOGroup *vfio_get_group_from_fd(int groupfd, AddressSpace *as, Error **errp);
void vfio_put_group(VFIOGroup *group);
int vfio_get_device(VFIOGroup *group, const char *name,
VFIODevice *vbasedev, Error **errp);
--
2.13.3
