drm/msm: Add opt-in for VM_BIND

Add a SET_PARAM for userspace to request to manage to the VM itself,
instead of getting a kernel managed VM.

In order to transition to a userspace managed VM, this param must be set
before any mappings are created.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>
Tested-by: Antonino Maniscalco <antomani103@gmail.com>
Reviewed-by: Antonino Maniscalco <antomani103@gmail.com>
Patchwork: https://patchwork.freedesktop.org/patch/661494/

1 files changed, 20 insertions, 2 deletions

diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index cf0805ed4c75..d75753745f12 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -232,9 +232,21 @@ static void load_gpu(struct drm_device *dev)
  */
 struct drm_gpuvm *msm_context_vm(struct drm_device *dev, struct msm_context *ctx)
 {
+	static DEFINE_MUTEX(init_lock);
 	struct msm_drm_private *priv = dev->dev_private;
-	if (!ctx->vm)
-		ctx->vm = msm_gpu_create_private_vm(priv->gpu, current);
+
+	/* Once ctx->vm is created it is valid for the lifetime of the context: */
+	if (ctx->vm)
+		return ctx->vm;
+
+	mutex_lock(&init_lock);
+	if (!ctx->vm) {
+		ctx->vm = msm_gpu_create_private_vm(
+			priv->gpu, current, !ctx->userspace_managed_vm);
+
+	}
+	mutex_unlock(&init_lock);
+
 	return ctx->vm;
 }
 
@@ -424,6 +436,9 @@ static int msm_ioctl_gem_info_iova(struct drm_device *dev,
 	if (!priv->gpu)
 		return -EINVAL;
 
+	if (msm_context_is_vmbind(ctx))
+		return UERR(EINVAL, dev, "VM_BIND is enabled");
+
 	if (should_fail(&fail_gem_iova, obj->size))
 		return -ENOMEM;
 
@@ -445,6 +460,9 @@ static int msm_ioctl_gem_info_set_iova(struct drm_device *dev,
 	if (!priv->gpu)
 		return -EINVAL;
 
+	if (msm_context_is_vmbind(ctx))
+		return UERR(EINVAL, dev, "VM_BIND is enabled");
+
 	/* Only supported if per-process address space is supported: */
 	if (priv->gpu->vm == vm)
 		return UERR(EOPNOTSUPP, dev, "requires per-process pgtables");