[RESEND PATCH] drm/i915/gvt: avoid dispatching workloads when host is resetting chip

[changbin.du at intel.com]

From: Changbin Du <changbin.du at intel.com>

It is meaningless that dispatch workload request to i915 when i915 is
resetting chip, especially when the hang is not caused by guest who own
the workload. This patch can reduce possible guest vgpu hang when host
or anthor VMs cause a chip reset.

Signed-off-by: Changbin Du <changbin.du at intel.com>
---
 drivers/gpu/drm/i915/gvt/scheduler.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c b/drivers/gpu/drm/i915/gvt/scheduler.c
index 7ea68a7..ca29fb4 100644
--- a/drivers/gpu/drm/i915/gvt/scheduler.c
+++ b/drivers/gpu/drm/i915/gvt/scheduler.c
@@ -406,8 +406,24 @@ static int workload_thread(void *priv)
 	gvt_dbg_core("workload thread for ring %d started\n", ring_id);
 
 	while (!kthread_should_stop()) {
+		workload = NULL;
 		add_wait_queue(&scheduler->waitq[ring_id], &wait);
 		do {
+			/**
+			 * we only wait for reset, but do not wait for wedged.
+			 * For wedged, just let the workloads fail when dispatch
+			 * them.
+			 */
+			if (i915_reset_in_progress(&gvt->dev_priv->gpu_error)) {
+				gvt_dbg_core("wait i915 finish chip reset\n");
+				ret = wait_on_bit_timeout(
+						&gvt->dev_priv->gpu_error.flags,
+						I915_RESET_IN_PROGRESS,
+						TASK_UNINTERRUPTIBLE,
+						HZ);
+				if (ret)
+					continue;
+			}
 			workload = pick_next_workload(gvt, ring_id);
 			if (workload)
 				break;
-- 
2.7.4