vgpu_cfg_space
pval = (u32 *)(vgpu_cfg_space(vgpu) + offset);
control = *(u16 *)(vgpu_cfg_space(vgpu) + MSI_CAP_CONTROL(offset));
addr = *(u32 *)(vgpu_cfg_space(vgpu) + MSI_CAP_ADDRESS(offset));
data = *(u16 *)(vgpu_cfg_space(vgpu) + MSI_CAP_DATA(offset));