A couple of the terms in the verse might need explaining:
'Bolverk' (literally 'Bad Worker') is one of Odin's many names/forms/character traits. If you're thinking that the title 'Bad Worker' means that Odin is a 'Bad Guy' then you should recall that pagans everywhere, including Europeans, didn't view the world as divided into a dualistic world of Good versus Evil. (The dualistic view is one that we picked up when we became Christians). On the contrary, they viewed things in a more balanced way, that the world is a complex thing that is highly dependent upon perspective. And I'm sure you'll all agree that perspective is very important when living in this world. For instance if a man wants to keep living, then he must kill a cow so that he can eat it and gain nourishment from it. This is obviously very bad for the cow who wants to keep living, but that's the way it is; even the cow must kills plants (or at least mutilate them) in order to survive. It's a simple thing that life for the human means death for the cow. Creation and destruction in one simple act. That's how intertwined the universe is. That's why we can't view it in dualistic Judeo-Christian terms of Good versus Evil. Rather, we must see that the world is complex and dependent upon perspective. Then we can understand this and make good of it in our own way.
'Har' (literally 'High') is another of Odin's names/forms/character traits.
'Frost Giants' are, in my personal opinion, something like natural phenomenon that don't change over time. This is because Giants ('Jotuns') are associated with natural features of the world, and there are two types of Giants: Frost Giants and Fire Giants; and because Fire is associated with dynamism and change, it makes logical sense that Frost Giants must be the opposite of dynamism and change i.e. predictable and unchanging.
Ins hindra dags
Háva ráðs at fregna
Háva höllu í
at Bölverki þeir spurðu
ef hann væri með böndum kominn
eða hefði honum Suttungr of sóit
On the next daythe frost giants went
to ask for Har's advice
in Har's hall:
they asked about Bolverkr,
whether he had come back among the gods,
or whether Suttungr had sacrificed him.