  The HPQCD collaboration has a program for determining the fundamental
constants of the Standard Model Lagrangian from lattice QCD. The most accurate
method of doing this uses the n_f=2+1 improved staggered MILC ensembles with
chiral fitting and multi-loop perturbative renormalisation to connect to the
continuum \msbar scheme. This program has already been very successful with the
recent strong coupling constant determination at three-loops from 28
observables at three lattice spacings, and the one-loop light quark mass
calculation last year. Here a preliminary result is presented for the
first-ever lattice determination of the two-loop multiplicative quark mass
renormalisation. The perturbative calculation involved was automated in the
generation of the Feynman rules, and the generation and coding of all of the
roughly 30 Feynman diagrams. The full formal framework for lattice quark mass
renormalisation is given, including the cancellation of infrared divergences in
intermediate diagrams. The result was checked by evaluation in three separate
gauges and by two authors independently, showing the incredible flexibility and
power of this perturbative methodology. Our preliminary result for the two-loop
perturbative matching factor, and of systematic errors associated with
higher-orders, gives \msbar masses at a 2 GeV scale of $m_s = 87(0)(4)(4)(0)$
MeV, and $\frac12(m_u+m_d) = 3.3(0)(2)(2)(0)$ MeV, where the respective
uncertainties are from lattice statistical, lattice systematic, perturbative,
and electromagnetic and isospin effects. The perturbative errors are a factor
of two smaller than in our previous study, and we anticipate reducing this
somewhat further from additional analysis of the systematics.
