E1000_VT_CTL
u32 vt_ctl = rd32(E1000_VT_CTL);
wr32(E1000_VT_CTL, vt_ctl);
regs_buff[37] = rd32(E1000_VT_CTL);
u32 vtctl = rd32(E1000_VT_CTL);
wr32(E1000_VT_CTL, vtctl);