[PATCH v4 2/6] drm/msm: Block VM_BIND for shared VMs

[Rob Clark]

We already block MSM_PARAM_EN_VM_BIND where per-process VMs are not
supported.  But in error paths when we actually try to create the VM
(allocation failures, etc) we could still end up with a shared-VM.

Since we need to create the VM lazily, for backwards compat, there
isn't really a better place to return an error.  But this isn't to
happen in practice.  Just block VM_BIND ioctls in this case so we
aren't giving userspace a way to manage the shared VM.

Signed-off-by: Rob Clark <robin.clark@xxxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/msm/msm_gem_vma.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_gem_vma.c b/drivers/gpu/drm/msm/msm_gem_vma.c
index 3ed05ab0eeef..06a3f2aa3ef0 100644
--- a/drivers/gpu/drm/msm/msm_gem_vma.c
+++ b/drivers/gpu/drm/msm/msm_gem_vma.c
@@ -954,7 +954,7 @@ msm_gem_vm_close(struct drm_gpuvm *gpuvm)
 
 
 static struct msm_vm_bind_job *
-vm_bind_job_create(struct drm_device *dev, struct drm_file *file,
+vm_bind_job_create(struct drm_device *dev, struct drm_file *file, struct drm_gpuvm *vm,
 		   struct msm_gpu_submitqueue *queue, uint32_t nr_ops)
 {
 	struct msm_vm_bind_job *job;
@@ -971,7 +971,7 @@ vm_bind_job_create(struct drm_device *dev, struct drm_file *file,
 		return ERR_PTR(ret);
 	}
 
-	job->vm = msm_context_vm(dev, queue->ctx);
+	job->vm = vm;
 	job->queue = queue;
 	INIT_LIST_HEAD(&job->vm_ops);
 
@@ -1430,6 +1430,7 @@ msm_ioctl_vm_bind(struct drm_device *dev, void *data, struct drm_file *file)
 	struct msm_drm_private *priv = dev->dev_private;
 	struct drm_msm_vm_bind *args = data;
 	struct msm_context *ctx = file->driver_priv;
+	struct drm_gpuvm *vm = msm_context_vm(dev, ctx);
 	struct msm_vm_bind_job *job = NULL;
 	struct msm_gpu *gpu = priv->gpu;
 	struct msm_gpu_submitqueue *queue;
@@ -1448,7 +1449,7 @@ msm_ioctl_vm_bind(struct drm_device *dev, void *data, struct drm_file *file)
 	 * Maybe we could allow just UNMAP ops?  OTOH userspace should just
 	 * immediately close the device file and all will be torn down.
 	 */
-	if (to_msm_vm(msm_context_vm(dev, ctx))->unusable)
+	if (to_msm_vm(vm)->unusable)
 		return UERR(EPIPE, dev, "context is unusable");
 
 	/*
@@ -1456,7 +1457,7 @@ msm_ioctl_vm_bind(struct drm_device *dev, void *data, struct drm_file *file)
 	 * place, if you haven't opted in to VM_BIND context.  But it is
 	 * cleaner / less confusing, to check this case directly.
 	 */
-	if (!msm_context_is_vmbind(ctx))
+	if (to_msm_vm(vm)->managed)
 		return UERR(EINVAL, dev, "context does not support vmbind");
 
 	if (args->flags & ~MSM_VM_BIND_FLAGS)
@@ -1479,7 +1480,7 @@ msm_ioctl_vm_bind(struct drm_device *dev, void *data, struct drm_file *file)
 		}
 	}
 
-	job = vm_bind_job_create(dev, file, queue, args->nr_ops);
+	job = vm_bind_job_create(dev, file, vm, queue, args->nr_ops);
 	if (IS_ERR(job)) {
 		ret = PTR_ERR(job);
 		goto out_post_unlock;
-- 
2.55.0