Va. Code § 37.2-901
In hearings and trials held pursuant to this chapter, respondents shall have the following rights:
In no event shall a respondent be permitted, as a part of any proceedings under this chapter, to raise challenges to the validity of his prior criminal or institutional convictions, charges, or sentences, or the computation of his term of confinement.
In no event shall a respondent be permitted to raise defenses or objections based on defects in the institution of proceedings under this chapter unless such defenses or objections have been raised in a written motion to dismiss, stating the legal and factual grounds therefor, filed with the court at least 14 days before the hearing or trial.
All proceedings conducted hereunder are civil proceedings. However, no discovery shall be allowed prior to the probable cause hearing. After the probable cause hearing, no discovery other than that provided in this section shall be allowed without prior leave of the court. Counsel for the respondent and any expert employed or appointed pursuant to this chapter may possess and copy the victim impact statement or presentence or postsentence report. In no event shall the respondent be permitted to retain or copy a victim impact statement or presentence or postsentence report.
Va. Code § 37.2-901