drm/amdgpu: add mes unmap legacy queue routine

For mes kiq has been taken over by mes sched, drv can't directly
use mes kiq to unmap queues. drv has to use mes sched api to
unmap legacy queue.

Signed-off-by: Jack Xiao <Jack.Xiao@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 84 insertions, 1 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.h
index 548015bb6ee7..25590b301f25 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.h
@@ -56,7 +56,7 @@ enum admgpu_mes_pipe {
 struct amdgpu_mes {
 	struct amdgpu_device            *adev;
 
-	struct mutex                    mutex;
+	struct mutex                    mutex_hidden;
 
 	struct idr                      pasid_idr;
 	struct idr                      gang_id_idr;
@@ -109,9 +109,11 @@ struct amdgpu_mes {
 	uint32_t			query_status_fence_offs;
 	uint64_t			query_status_fence_gpu_addr;
 	uint64_t			*query_status_fence_ptr;
+	uint32_t			saved_flags;
 
 	/* initialize kiq pipe */
 	int                             (*kiq_hw_init)(struct amdgpu_device *adev);
+	int                             (*kiq_hw_fini)(struct amdgpu_device *adev);
 
 	/* ip specific functions */
 	const struct amdgpu_mes_funcs   *funcs;
@@ -198,6 +200,10 @@ struct mes_add_queue_input {
 	uint64_t	wptr_addr;
 	uint32_t	queue_type;
 	uint32_t	paging;
+	uint32_t        gws_base;
+	uint32_t        gws_size;
+	uint64_t	tba_addr;
+	uint64_t	tma_addr;
 };
 
 struct mes_remove_queue_input {
@@ -205,6 +211,16 @@ struct mes_remove_queue_input {
 	uint64_t	gang_context_addr;
 };
 
+struct mes_unmap_legacy_queue_input {
+	enum amdgpu_unmap_queues_action    action;
+	uint32_t                           queue_type;
+	uint32_t                           doorbell_offset;
+	uint32_t                           pipe_id;
+	uint32_t                           queue_id;
+	uint64_t                           trail_fence_addr;
+	uint64_t                           trail_fence_data;
+};
+
 struct mes_suspend_gang_input {
 	bool		suspend_all_gangs;
 	uint64_t	gang_context_addr;
@@ -224,6 +240,9 @@ struct amdgpu_mes_funcs {
 	int (*remove_hw_queue)(struct amdgpu_mes *mes,
 			       struct mes_remove_queue_input *input);
 
+	int (*unmap_legacy_queue)(struct amdgpu_mes *mes,
+				  struct mes_unmap_legacy_queue_input *input);
+
 	int (*suspend_gang)(struct amdgpu_mes *mes,
 			    struct mes_suspend_gang_input *input);
 
@@ -232,6 +251,7 @@ struct amdgpu_mes_funcs {
 };
 
 #define amdgpu_mes_kiq_hw_init(adev) (adev)->mes.kiq_hw_init((adev))
+#define amdgpu_mes_kiq_hw_fini(adev) (adev)->mes.kiq_hw_fini((adev))
 
 int amdgpu_mes_ctx_get_offs(struct amdgpu_ring *ring, unsigned int id_offs);
 
@@ -255,6 +275,11 @@ int amdgpu_mes_add_hw_queue(struct amdgpu_device *adev, int gang_id,
 			    int *queue_id);
 int amdgpu_mes_remove_hw_queue(struct amdgpu_device *adev, int queue_id);
 
+int amdgpu_mes_unmap_legacy_queue(struct amdgpu_device *adev,
+				  struct amdgpu_ring *ring,
+				  enum amdgpu_unmap_queues_action action,
+				  u64 gpu_addr, u64 seq);
+
 int amdgpu_mes_add_ring(struct amdgpu_device *adev, int gang_id,
 			int queue_type, int idx,
 			struct amdgpu_mes_ctx_data *ctx_data,
@@ -280,4 +305,62 @@ unsigned int amdgpu_mes_get_doorbell_dw_offset_in_bar(
 					uint32_t doorbell_index,
 					unsigned int doorbell_id);
 int amdgpu_mes_doorbell_process_slice(struct amdgpu_device *adev);
+
+/*
+ * MES lock can be taken in MMU notifiers.
+ *
+ * A bit more detail about why to set no-FS reclaim with MES lock:
+ *
+ * The purpose of the MMU notifier is to stop GPU access to memory so
+ * that the Linux VM subsystem can move pages around safely. This is
+ * done by preempting user mode queues for the affected process. When
+ * MES is used, MES lock needs to be taken to preempt the queues.
+ *
+ * The MMU notifier callback entry point in the driver is
+ * amdgpu_mn_invalidate_range_start_hsa. The relevant call chain from
+ * there is:
+ * amdgpu_amdkfd_evict_userptr -> kgd2kfd_quiesce_mm ->
+ * kfd_process_evict_queues -> pdd->dev->dqm->ops.evict_process_queues
+ *
+ * The last part of the chain is a function pointer where we take the
+ * MES lock.
+ *
+ * The problem with taking locks in the MMU notifier is, that MMU
+ * notifiers can be called in reclaim-FS context. That's where the
+ * kernel frees up pages to make room for new page allocations under
+ * memory pressure. While we are running in reclaim-FS context, we must
+ * not trigger another memory reclaim operation because that would
+ * recursively reenter the reclaim code and cause a deadlock. The
+ * memalloc_nofs_save/restore calls guarantee that.
+ *
+ * In addition we also need to avoid lock dependencies on other locks taken
+ * under the MES lock, for example reservation locks. Here is a possible
+ * scenario of a deadlock:
+ * Thread A: takes and holds reservation lock | triggers reclaim-FS |
+ * MMU notifier | blocks trying to take MES lock
+ * Thread B: takes and holds MES lock | blocks trying to take reservation lock
+ *
+ * In this scenario Thread B gets involved in a deadlock even without
+ * triggering a reclaim-FS operation itself.
+ * To fix this and break the lock dependency chain you'd need to either:
+ * 1. protect reservation locks with memalloc_nofs_save/restore, or
+ * 2. avoid taking reservation locks under the MES lock.
+ *
+ * Reservation locks are taken all over the kernel in different subsystems, we
+ * have no control over them and their lock dependencies.So the only workable
+ * solution is to avoid taking other locks under the MES lock.
+ * As a result, make sure no reclaim-FS happens while holding this lock anywhere
+ * to prevent deadlocks when an MMU notifier runs in reclaim-FS context.
+ */
+static inline void amdgpu_mes_lock(struct amdgpu_mes *mes)
+{
+	mutex_lock(&mes->mutex_hidden);
+	mes->saved_flags = memalloc_noreclaim_save();
+}
+
+static inline void amdgpu_mes_unlock(struct amdgpu_mes *mes)
+{
+	memalloc_noreclaim_restore(mes->saved_flags);
+	mutex_unlock(&mes->mutex_hidden);
+}
 #endif /* __AMDGPU_MES_H__ */