[PATCH] drm/xe: Restrict user fences to long running VMs

[Matthew Brost]

User fences are intended to be used on long running VMs, enforce this
restriction. This addresses possible concerns of using user fences in
dma-fence and having the dma-fence signal before the user fence.

Fixes: d1df9bfbf68c ("drm/xe: Only allow 1 ufence per exec / bind IOCTL")
Fixes: dd08ebf6c352 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
Cc: Thomas Hellström <thomas.hellstrom at linux.intel.com>
Cc: stable at vger.kernel.org
Signed-off-by: Matthew Brost <matthew.brost at intel.com>
---
 drivers/gpu/drm/xe/xe_exec.c | 3 ++-
 drivers/gpu/drm/xe/xe_vm.c   | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_exec.c b/drivers/gpu/drm/xe/xe_exec.c
index 97eeb973e897..a145813ad229 100644
--- a/drivers/gpu/drm/xe/xe_exec.c
+++ b/drivers/gpu/drm/xe/xe_exec.c
@@ -168,7 +168,8 @@ int xe_exec_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
 			num_ufence++;
 	}
 
-	if (XE_IOCTL_DBG(xe, num_ufence > 1)) {
+	if (XE_IOCTL_DBG(xe, num_ufence > 1) ||
+	    XE_IOCTL_DBG(xe, num_ufence && !xe_vm_in_lr_mode(vm))) {
 		err = -EINVAL;
 		goto err_syncs;
 	}
diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
index 26b409e1b0f0..85da3a8a83b6 100644
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -3226,7 +3226,8 @@ int xe_vm_bind_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
 			num_ufence++;
 	}
 
-	if (XE_IOCTL_DBG(xe, num_ufence > 1)) {
+	if (XE_IOCTL_DBG(xe, num_ufence > 1) ||
+	    XE_IOCTL_DBG(xe, num_ufence && !xe_vm_in_lr_mode(vm))) {
 		err = -EINVAL;
 		goto free_syncs;
 	}
-- 
2.34.1