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authorDavid Gibson <david@gibson.dropbear.id.au>2016-03-09 11:56:06 +1100
committerDavid Gibson <david@gibson.dropbear.id.au>2016-03-16 09:55:10 +1100
commit3153119e9bb79ebd82e08d2fde80d1c3a039b6b2 (patch)
treeb7874a5faa5fd67c65fe3fa1e92aebf127fb686b /hw/vfio
parentf1a6cf3ef734aab142d5f7ce52e219474ababf6b (diff)
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vfio: Start improving VFIO/EEH interface
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 with exactly one 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 <david@gibson.dropbear.id.au> Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru> Acked-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'hw/vfio')
-rw-r--r--hw/vfio/common.c95
1 files changed, 95 insertions, 0 deletions
diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 96ccb79..0636bb1 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -1137,3 +1137,98 @@ 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)
+{
+ /*
+ * As of 2016-03-04 (linux-4.5) the host kernel EEH/VFIO
+ * implementation is broken if there are multiple groups in a
+ * container. The hardware works in units of Partitionable
+ * Endpoints (== IOMMU groups) and the EEH operations naively
+ * iterate across all groups in the container, without any logic
+ * to make sure the groups have their state synchronized. For
+ * certain operations (ENABLE) that might be ok, until an error
+ * occurs, but for others (GET_STATE) it's clearly broken.
+ */
+
+ /*
+ * XXX Once fixed kernels exist, test for them here
+ */
+
+ 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: "
+ "kernel requires a container with exactly one group", 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);
+
+ if (!container) {
+ return -ENODEV;
+ }
+ return vfio_eeh_container_op(container, op);
+}