drm/i915/gvt: vGPU MMIO virtualization

This patch introduces the generic vGPU MMIO emulation intercept
framework.  The MPT modules will request GVT-g core logic to
emulate MMIO read/write through IO emulation operations
callback when hypervisor trapped a guest GTTMMIO read/write.

Signed-off-by: Zhi Wang <zhi.a.wang@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

drivers/gpu/drm/i915/gvt/vgpu.c

@@ -52,6 +52,11 @@ static int setup_vgpu_mmio(struct intel_vgpu *vgpu)
 
 	memcpy(vgpu->mmio.vreg, gvt->firmware.mmio, info->mmio_size);
 	memcpy(vgpu->mmio.sreg, gvt->firmware.mmio, info->mmio_size);
+
+	vgpu_vreg(vgpu, GEN6_GT_THREAD_STATUS_REG) = 0;
+
+	/* set the bit 0:2(Core C-State ) to C0 */
+	vgpu_vreg(vgpu, GEN6_GT_CORE_STATUS) = 0;
 	return 0;
 }