If you're mirroring the database then the HA is at the sql server level, introducing VMotion will not help.

Essentially there shouldnt be any disconnection issue, but if however during transit from one host to another the network is breaking down you may quickly hit the mirror session timeout. You should'nt lose transactions it may just be that the transaction is still in the principal send queue.

First thing i would do is stop VMotioning the mirror servers.

Did you try resuming the mirror session?

When patching a mirror node you patch the passive node first, reboot if necessary and then manually failover to the mirror as new principal. Patch the new passive node and reboot, then fail back if required.