It takes some "fine print" reading to find it, but here's the relevant commentary in open:

Since v5.8.0, perl has built using PerlIO by default. Unless you've changed this (i.e. Configure -Uuseperlio), you can open file handles to "in memory" files held in Perl scalars via:

    open($fh, '>', \$variable) || ..
[download]

Of course in your case you'll want to open the in memory file for reading, not writing. Then all you'll have to do is pass that filehandle to Text::xSV as you demonstrated in your original post. That ought to do the trick.