This study is sponsor-open, investigator-blinded, participant-blinded, randomized, placebo-controlled, single-ascending dose (SAD) and multiple-ascending dose (MAD) study that will evaluate the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of RO7049389 following oral administration in healthy volunteers and chronic HBV infected participants. The effect of food on the PK of RO7049389 and the effect of multiple dosing of RO7049389 on the PK of a single oral microdose of midazolam will be evaluated. The study will be conducted in two parts: Part 1 (1a [SAD cohort], 1b [Food-effect SAD cohort], 1c [MAD Cohort]) in healthy volunteers and Part 2 (Proof of mechanism [POM]) in chronic HBV infected participants.