In the beginning of Act 2 of Shakespeare's Macbeth, how do Banquo and Macbeth regard each other?

At the beginning of Act Two of Shakespeare's
Macbeth, Macbeth and Banquo have become very different people than
who they were at the play's start.

It is after the banquet
to honor Duncan at Inverness (Macbeth's home), and Banquo and Macbeth meet by chance.
Banquo mentions that he has dreamt of the witches, and comments that some of what the
witches have said has come true for Macbeth. (This will be a concern to Macbeth because
Banquo was the only one with him to hear the predictions, especially the one about
Macbeth being king...this would make the honorable Banquo suspicious if Duncan were to
die at Macbeth's castle.)

Macbeth lies and says he doesn't
think about the predictions. However, he asks Banquo if they could discuss the situation
again in the near future. Banquo agrees to do so, whenever it is convenient to Macbeth.
(This is clearly just casual discussion.)

With some
foreshadowing for the audience, Macbeth approaches Banquo to see how far he can trust
his friend. Macbeth says that if Banquo will have his back (support him) when the time
is right, Macbeth will make it worth his while (reward
him).

Banquo, unlike Macbeth, cannot be swayed from his
honor and duty to king and his own sense of moral character. He
responds:

So I
lose none/ In seeking to augment it, but still keep / My bosom franchised and allegiance
clear, / I shall be
counselled.

In other words,
Banquo is telling Macbeth that as long as he does not need to compromise his sense of
right and wrong, and as long as he can serve his king loyally, he will consider what
Macbeth might ask of him. Basically, Banquo has told Macbeth that he will remain true to
the things he holds dear and honorable.

This is, of course,
important for Macbeth to know; if Duncan dies on Macbeth's watch, it will be Banquo who
will challenge his friend's part in the murder, most especially because of the witches'
predictions. This also shows the audience how distanced the two men have become, when
they were once both honorable servants to
Duncan.

So although they seem friendly enough, Macbeth is
keeping his ideas of the witches' predictions tucked away, and asking to see how far he
can trust Banquo. Banquo is full of praise for how graciously the Macbeths have
entertained the king, but he is also no fool: he can imagine, I'm sure, that Macbeth is
asking where his allegiance lies, especially with Macbeth's promise of a reward under
the right circumstances. Banquo lets Macbeth know, in no uncertain terms, that he is
honor-bound to support his king and will follow the dictates of his heart to do what is
ethically correct. Each man knows where the other stands.