drm/i915/gvt: introuduce intel_vgpu_reset_gtt() to reset gtt

This patch introduces a new function intel_vgpu_reset_gtt() to reset
the all GTT related status, including GGTT, PPGTT, scratch page. This
function can free all shadowed PPGTT, clear all GGTT entry, and clear
scratch page to all zero. After this, we can ensure no gtt related
information can be leakaged from one VM to anothor one when assign
vgpu instance across different VMs (not simultaneously).

Signed-off-by: Changbin Du <changbin.du@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
index 3cf0df0bb391..47dec4acf7ff 100644
--- a/drivers/gpu/drm/i915/gvt/gtt.c
+++ b/drivers/gpu/drm/i915/gvt/gtt.c
@@ -2277,3 +2277,30 @@ void intel_vgpu_reset_ggtt(struct intel_vgpu *vgpu)
 	for (offset = 0; offset < num_entries; offset++)
 		ops->set_entry(NULL, &e, index + offset, false, 0, vgpu);
 }
+
+/**
+ * intel_vgpu_reset_gtt - reset the all GTT related status
+ * @vgpu: a vGPU
+ * @dmlr: true for vGPU Device Model Level Reset, false for GT Reset
+ *
+ * This function is called from vfio core to reset reset all
+ * GTT related status, including GGTT, PPGTT, scratch page.
+ *
+ */
+void intel_vgpu_reset_gtt(struct intel_vgpu *vgpu, bool dmlr)
+{
+	int i;
+
+	ppgtt_free_all_shadow_page(vgpu);
+	if (!dmlr)
+		return;
+
+	intel_vgpu_reset_ggtt(vgpu);
+
+	/* clear scratch page for security */
+	for (i = GTT_TYPE_PPGTT_PTE_PT; i < GTT_TYPE_MAX; i++) {
+		if (vgpu->gtt.scratch_pt[i].page != NULL)
+			memset(page_address(vgpu->gtt.scratch_pt[i].page),
+				0, PAGE_SIZE);
+	}
+}