[PATCH] drm/i915/gvt: Refine new_mmio_info to override the added MMIO_reg

[Zhao Yakui]

GVT-g uses new_mmio_info function to track the required the mmio_reg. If the
required mmio_reg is already added, error is returned. If one platform hopes
to add new specific MMIO read/write callback for one mmio_reg,  the change
needs to be applied on all the platforms.

So the new_mmio_info is implemented as override. If it is already added, it
will be replaced by the new attributes(mask, read/write callback and so on).

Signed-off-by: Zhao Yakui <yakui.zhao at intel.com>
---
 drivers/gpu/drm/i915/gvt/handlers.c | 25 +++++++++++--------------
 1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/handlers.c b/drivers/gpu/drm/i915/gvt/handlers.c
index 653ba2b..a7bf6d5 100644
--- a/drivers/gpu/drm/i915/gvt/handlers.c
+++ b/drivers/gpu/drm/i915/gvt/handlers.c
@@ -107,22 +107,19 @@ static int new_mmio_info(struct intel_gvt *gvt,
 	end = offset + size;
 
 	for (i = start; i < end; i += 4) {
-		info = kzalloc(sizeof(*info), GFP_KERNEL);
-		if (!info)
-			return -ENOMEM;
-
-		info->offset = i;
-		p = find_mmio_info(gvt, info->offset);
+		p = find_mmio_info(gvt, i);
 		if (p) {
-			WARN(1, "dup mmio definition offset %x\n",
-				info->offset);
-			kfree(info);
+			/* It will be removed from hash_list if found */
+			hash_del(&p->node);
+			info = p;
+			gvt_dbg_mmio("VGPU MMIO_reg %x is added. Override\n",
+					p->offset);
+		} else {
+			info = kzalloc(sizeof(*info), GFP_KERNEL);
+			if (!info)
+				return -ENOMEM;
 
-			/* We return -EEXIST here to make GVT-g load fail.
-			 * So duplicated MMIO can be found as soon as
-			 * possible.
-			 */
-			return -EEXIST;
+			info->offset = i;
 		}
 
 		info->ro_mask = ro_mask;
-- 
2.7.4