_bb_id++) \
if (virtio_mem_bbm_get_bb_state(_vm, _bb_id) == _state)
+#define virtio_mem_bbm_for_each_bb_rev(_vm, _bb_id, _state) \
+ for (_bb_id = vm->bbm.next_bb_id - 1; \
+ _bb_id >= vm->bbm.first_bb_id && _vm->bbm.bb_count[_state]; \
+ _bb_id--) \
+ if (virtio_mem_bbm_get_bb_state(_vm, _bb_id) == _state)
+
/*
* Set the state of a memory block, taking care of the state counter.
*/
return virtio_mem_remove_memory(vm, addr, size);
}
+/*
+ * See virtio_mem_remove_memory(): Try to remove all Linux memory blocks covered
+ * by the big block.
+ */
+static int virtio_mem_bbm_remove_bb(struct virtio_mem *vm, unsigned long bb_id)
+{
+ const uint64_t addr = virtio_mem_bb_id_to_phys(vm, bb_id);
+ const uint64_t size = vm->bbm.bb_size;
+
+ return virtio_mem_remove_memory(vm, addr, size);
+}
+
/*
* Try offlining and removing memory from Linux.
*
return virtio_mem_offline_and_remove_memory(vm, addr, size);
}
+/*
+ * See virtio_mem_offline_and_remove_memory(): Try to offline and remove a
+ * all Linux memory blocks covered by the big block.
+ */
+static int virtio_mem_bbm_offline_and_remove_bb(struct virtio_mem *vm,
+ unsigned long bb_id)
+{
+ const uint64_t addr = virtio_mem_bb_id_to_phys(vm, bb_id);
+ const uint64_t size = vm->bbm.bb_size;
+
+ return virtio_mem_offline_and_remove_memory(vm, addr, size);
+}
+
/*
* Trigger the workqueue so the device can perform its magic.
*/
return rc;
}
+/*
+ * Try to offline and remove a big block from Linux and unplug it. Will fail
+ * with -EBUSY if some memory is busy and cannot get unplugged.
+ *
+ * Will modify the state of the memory block. Might temporarily drop the
+ * hotplug_mutex.
+ */
+static int virtio_mem_bbm_offline_remove_and_unplug_bb(struct virtio_mem *vm,
+ unsigned long bb_id)
+{
+ int rc;
+
+ if (WARN_ON_ONCE(virtio_mem_bbm_get_bb_state(vm, bb_id) !=
+ VIRTIO_MEM_BBM_BB_ADDED))
+ return -EINVAL;
+
+ rc = virtio_mem_bbm_offline_and_remove_bb(vm, bb_id);
+ if (rc)
+ return rc;
+
+ rc = virtio_mem_bbm_unplug_bb(vm, bb_id);
+ if (rc)
+ virtio_mem_bbm_set_bb_state(vm, bb_id,
+ VIRTIO_MEM_BBM_BB_PLUGGED);
+ else
+ virtio_mem_bbm_set_bb_state(vm, bb_id,
+ VIRTIO_MEM_BBM_BB_UNUSED);
+ return rc;
+}
+
+/*
+ * Try to remove a big block from Linux and unplug it. Will fail with
+ * -EBUSY if some memory is online.
+ *
+ * Will modify the state of the memory block.
+ */
+static int virtio_mem_bbm_remove_and_unplug_bb(struct virtio_mem *vm,
+ unsigned long bb_id)
+{
+ int rc;
+
+ if (WARN_ON_ONCE(virtio_mem_bbm_get_bb_state(vm, bb_id) !=
+ VIRTIO_MEM_BBM_BB_ADDED))
+ return -EINVAL;
+
+ rc = virtio_mem_bbm_remove_bb(vm, bb_id);
+ if (rc)
+ return -EBUSY;
+
+ rc = virtio_mem_bbm_unplug_bb(vm, bb_id);
+ if (rc)
+ virtio_mem_bbm_set_bb_state(vm, bb_id,
+ VIRTIO_MEM_BBM_BB_PLUGGED);
+ else
+ virtio_mem_bbm_set_bb_state(vm, bb_id,
+ VIRTIO_MEM_BBM_BB_UNUSED);
+ return rc;
+}
+
+/*
+ * Test if a big block is completely offline.
+ */
+static bool virtio_mem_bbm_bb_is_offline(struct virtio_mem *vm,
+ unsigned long bb_id)
+{
+ const unsigned long start_pfn = PFN_DOWN(virtio_mem_bb_id_to_phys(vm, bb_id));
+ const unsigned long nr_pages = PFN_DOWN(vm->bbm.bb_size);
+ unsigned long pfn;
+
+ for (pfn = start_pfn; pfn < start_pfn + nr_pages;
+ pfn += PAGES_PER_SECTION) {
+ if (pfn_to_online_page(pfn))
+ return false;
+ }
+
+ return true;
+}
+
+static int virtio_mem_bbm_unplug_request(struct virtio_mem *vm, uint64_t diff)
+{
+ uint64_t nb_bb = diff / vm->bbm.bb_size;
+ uint64_t bb_id;
+ int rc;
+
+ if (!nb_bb)
+ return 0;
+
+ /* Try to unplug completely offline big blocks first. */
+ virtio_mem_bbm_for_each_bb_rev(vm, bb_id, VIRTIO_MEM_BBM_BB_ADDED) {
+ cond_resched();
+ /*
+ * As we're holding no locks, this check is racy as memory
+ * can get onlined in the meantime - but we'll fail gracefully.
+ */
+ if (!virtio_mem_bbm_bb_is_offline(vm, bb_id))
+ continue;
+ rc = virtio_mem_bbm_remove_and_unplug_bb(vm, bb_id);
+ if (rc == -EBUSY)
+ continue;
+ if (!rc)
+ nb_bb--;
+ if (rc || !nb_bb)
+ return rc;
+ }
+
+ if (!unplug_online)
+ return 0;
+
+ /* Try to unplug any big blocks. */
+ virtio_mem_bbm_for_each_bb_rev(vm, bb_id, VIRTIO_MEM_BBM_BB_ADDED) {
+ cond_resched();
+ rc = virtio_mem_bbm_offline_remove_and_unplug_bb(vm, bb_id);
+ if (rc == -EBUSY)
+ continue;
+ if (!rc)
+ nb_bb--;
+ if (rc || !nb_bb)
+ return rc;
+ }
+
+ return nb_bb ? -EBUSY : 0;
+}
+
/*
* Try to unplug the requested amount of memory.
*/
{
if (vm->in_sbm)
return virtio_mem_sbm_unplug_request(vm, diff);
- return -EBUSY;
+ return virtio_mem_bbm_unplug_request(vm, diff);
}
/*