This will call FITRIM within guest. The API has 4 arguments,
however, only 2 will be used for now (@dom and @minumum).
The rest two are there if in future qemu guest agent learns them.
s/in future/in the future/
+/**
+ * virDomainFSTrim:
+ * @dom: a domain object
+ * @mountPoint: which mount point trim
s/trim/to trim/
+ * @minimum: Minimum contiguous free range to discard in bytes
+ * @flags: extra flags, not used yet, so callers should always pass
0
+ *
+ * Calls FITRIM within the guest (hence guest agent may be
+ * required depending on hypervisor used). Either call it on each
+ * mounted filesystem (@mountPoint is NULL) or just on specified
+ * @mountPoint. @minimum tell that free ranges smaller than this
s/tell/hints/
+ * may be ignored (this is a hint and the guest may not respect
+ * it). By increasing this value, the fstrim operation will
+ * complete more quickly for filesystems with badly fragmented
+ * free space, although not all blocks will be discarded.
Maybe mention that the command may fail if @minimum is not 0.