At present the code handling IBM's Enhanced Error Handling (EEH) interface
on VFIO devices operates by bypassing the usual VFIO logic with
vfio_container_ioctl(). That's a poorly designed interface with unclear
semantics about exactly what can be operated on.
In particular it operates on a single vfio container internally (hence the
name), but takes an address space and group id, from which it deduces the
container in a rather roundabout way. groupids are something that code
outside vfio shouldn't even be aware of.
This patch creates new interfaces for EEH operations. Internally we
have vfio_eeh_container_op() which takes a VFIOContainer object
directly. For external use we have vfio_eeh_as_ok() which determines
if an AddressSpace is usable for EEH (at present this means it has a
single container and at most a single group attached), and
vfio_eeh_as_op() which will perform an operation on an AddressSpace in
the unambiguous case, and otherwise returns an error.
This interface still isn't great, but it's enough of an improvement to
allow a number of cleanups in other places.
Signed-off-by: David Gibson <da...@gibson.dropbear.id.au>
---
hw/vfio/common.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++
include/hw/vfio/vfio.h | 2 ++
2 files changed, 86 insertions(+)
diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 607ec70..b61118e 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -1003,3 +1003,87 @@ int vfio_container_ioctl(AddressSpace *as, int32_t
groupid,
return vfio_container_do_ioctl(as, groupid, req, param);
}
+
+/*
+ * Interfaces for IBM EEH (Enhanced Error Handling)
+ */
+static bool vfio_eeh_container_ok(VFIOContainer *container)
+{
+ /* A broken kernel implementation means EEH operations won't work
+ * correctly if there are multiple groups in a container. So
+ * return true only if there is exactly one group attached to the
+ * container */
+
+ if (QLIST_EMPTY(&container->group_list)) {
+ return false;
+ }
+
+ if (QLIST_NEXT(QLIST_FIRST(&container->group_list), container_next)) {
+ return false;
+ }
+
+ return true;
+}
+
+static int vfio_eeh_container_op(VFIOContainer *container, uint32_t op)
+{
+ struct vfio_eeh_pe_op pe_op = {
+ .argsz = sizeof(pe_op),
+ .op = op,
+ };
+ int ret;
+
+ if (!vfio_eeh_container_ok(container)) {
+ error_report("vfio/eeh: EEH_PE_OP 0x%x called on container"
+ " with multiple groups", op);
+ return -EPERM;
+ }
+
+ ret = ioctl(container->fd, VFIO_EEH_PE_OP, &pe_op);
+ if (ret < 0) {
+ error_report("vfio/eeh: EEH_PE_OP 0x%x failed: %m", op);
+ return -errno;
+ }
+
+ return 0;
+}
+
+static VFIOContainer *vfio_eeh_as_container(AddressSpace *as)
+{
+ VFIOAddressSpace *space = vfio_get_address_space(as);
+ VFIOContainer *container = NULL;
+
+ if (QLIST_EMPTY(&space->containers)) {
+ /* No containers to act on */
+ goto out;
+ }
+
+ container = QLIST_FIRST(&space->containers);
+
+ if (QLIST_NEXT(container, next)) {
+ /* We don't yet have logic to synchronize EEH state across
+ * multiple containers */
+ container = NULL;
+ goto out;
+ }
+
+out:
+ vfio_put_address_space(space);
+ return container;
+}
+
+bool vfio_eeh_as_ok(AddressSpace *as)
+{
+ VFIOContainer *container = vfio_eeh_as_container(as);
+
+ return (container != NULL) && vfio_eeh_container_ok(container);
+}
+
+int vfio_eeh_as_op(AddressSpace *as, uint32_t op)
+{
+ VFIOContainer *container = vfio_eeh_as_container(as);
+
+ /* Shouldn't be called unless vfio_eeh_as_ok() returned true */
+ assert(container);
+ return vfio_eeh_container_op(container, op);
+}
diff --git a/include/hw/vfio/vfio.h b/include/hw/vfio/vfio.h
index 0b26cd8..fd3933b 100644
--- a/include/hw/vfio/vfio.h
+++ b/include/hw/vfio/vfio.h
@@ -5,5 +5,7 @@
extern int vfio_container_ioctl(AddressSpace *as, int32_t groupid,
int req, void *param);
+bool vfio_eeh_as_ok(AddressSpace *as);
+int vfio_eeh_as_op(AddressSpace *as, uint32_t op);
#endif
--
2.5.0
