I do not find any Charles D. Hall listed in James I. Robertson's 4th Va. Inf, Virginia Regimental Histories. A Charles D. Hall was a member of Co. B, 42nd Va., a company raised in Floyd County. There are a total of 20 Halls listed as members of the 42nd Va. In addition to those in Co. B, most were in Co. D from Campbell County, some from Co. K, which was from Franklin County, and one in Co. E, raised in Roanoke County. These Halls have names similar to the ones you are looking for, but given the common last name of Hall, it's hard to say whether the men in the 42nd are those you are looking for.