Thanks for the replies everyone. I see a lot of good points in these posts. I guess a knife is a deadly weapon period, no matter how it is used. That's what I was thinking, I just wanted to know what others thought.
Joe-Bob, according to this I see no length limitations:
§ 18.2-308. Personal protection; carrying concealed weapons; when lawful to carry.
A. If any person carries about his person, hidden from common observation, (i) any pistol, revolver, or other weapon designed or intended to propel a missile of any kind by action of an explosion of any combustible material; (ii) any dirk, bowie knife, switchblade knife, ballistic knife, machete, razor, slingshot, spring stick, metal knucks, or blackjack; (iii) any flailing instrument consisting of two or more rigid parts connected in such a manner as to allow them to swing freely, which may be known as a nun chahka, nun chuck, nunchaku, shuriken, or fighting chain; (iv) any disc, of whatever configuration, having at least two points or pointed blades which is designed to be thrown or propelled and which may be known as a throwing star or oriental dart; or (v) any weapon of like kind as those enumerated in this subsection, he shall be guilty of a Class 1 misdemeanor. A second violation of this section or a conviction under this section subsequent to any conviction under any substantially similar ordinance of any county, city, or town shall be punishable as a Class 6 felony, and a third or subsequent such violation shall be punishable as a Class 5 felony. For the purpose of this section, a weapon shall be deemed to be hidden from common observation when it is observable but is of such deceptive appearance as to disguise the weapon's true nature.
I'm not sure if it could be considered a dirk or not. If not, I should be ok.