[Intel-xe] [PATCH v2 11/31] drm/xe/guc: Use doorbells for submission if possible
Thomas Hellström
thomas.hellstrom at linux.intel.com
Tue May 9 13:00:17 UTC 2023
On 5/2/23 02:17, Matthew Brost wrote:
> We have 256 doorbells (on most platforms) that we can allocate to bypass
> using the H2G channel for submission. This will avoid contention on the
> CT mutex.
>
> Signed-off-by: Matthew Brost <matthew.brost at intel.com>
> Suggested-by: Faith Ekstrand <faith.ekstrand at collabora.com>
Could we describe in a DOC section how doorbells are distributed and if
there are any suggestions on how to improve that moving forward?
/Thomas
> ---
> drivers/gpu/drm/xe/regs/xe_guc_regs.h | 1 +
> drivers/gpu/drm/xe/xe_guc.c | 6 +
> drivers/gpu/drm/xe/xe_guc_engine_types.h | 7 +
> drivers/gpu/drm/xe/xe_guc_submit.c | 295 ++++++++++++++++++++++-
> drivers/gpu/drm/xe/xe_guc_submit.h | 1 +
> drivers/gpu/drm/xe/xe_guc_types.h | 4 +
> drivers/gpu/drm/xe/xe_trace.h | 5 +
> 7 files changed, 315 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/regs/xe_guc_regs.h b/drivers/gpu/drm/xe/regs/xe_guc_regs.h
> index 37e0ac550931..11b117293a62 100644
> --- a/drivers/gpu/drm/xe/regs/xe_guc_regs.h
> +++ b/drivers/gpu/drm/xe/regs/xe_guc_regs.h
> @@ -109,6 +109,7 @@ struct guc_doorbell_info {
>
> #define DIST_DBS_POPULATED XE_REG(0xd08)
> #define DOORBELLS_PER_SQIDI_MASK REG_GENMASK(23, 16)
> +#define DOORBELLS_PER_SQIDI_SHIFT 16
> #define SQIDIS_DOORBELL_EXIST_MASK REG_GENMASK(15, 0)
>
> #define GUC_BCS_RCS_IER XE_REG(0xC550)
> diff --git a/drivers/gpu/drm/xe/xe_guc.c b/drivers/gpu/drm/xe/xe_guc.c
> index 89d20faced19..0c87f78a868b 100644
> --- a/drivers/gpu/drm/xe/xe_guc.c
> +++ b/drivers/gpu/drm/xe/xe_guc.c
> @@ -297,6 +297,12 @@ int xe_guc_init(struct xe_guc *guc)
> */
> int xe_guc_init_post_hwconfig(struct xe_guc *guc)
> {
> + int ret;
> +
> + ret = xe_guc_submit_init_post_hwconfig(guc);
> + if (ret)
> + return ret;
> +
> return xe_guc_ads_init_post_hwconfig(&guc->ads);
> }
>
> diff --git a/drivers/gpu/drm/xe/xe_guc_engine_types.h b/drivers/gpu/drm/xe/xe_guc_engine_types.h
> index 5d83132034a6..420b7f53e649 100644
> --- a/drivers/gpu/drm/xe/xe_guc_engine_types.h
> +++ b/drivers/gpu/drm/xe/xe_guc_engine_types.h
> @@ -12,6 +12,7 @@
> #include <drm/gpu_scheduler.h>
>
> struct dma_fence;
> +struct xe_bo;
> struct xe_engine;
>
> /**
> @@ -37,6 +38,10 @@ struct xe_guc_engine {
> struct work_struct fini_async;
> /** @resume_time: time of last resume */
> u64 resume_time;
> + /** @doorbell_bo: BO for memory doorbell */
> + struct xe_bo *doorbell_bo;
> + /** @doorbell_offset: MMIO doorbell offset */
> + u32 doorbell_offset;
> /** @state: GuC specific state for this xe_engine */
> atomic_t state;
> /** @wqi_head: work queue item tail */
> @@ -45,6 +50,8 @@ struct xe_guc_engine {
> u32 wqi_tail;
> /** @id: GuC id for this xe_engine */
> u16 id;
> + /** @doorbell_id: doorbell id */
> + u16 doorbell_id;
> /** @suspend_wait: wait queue used to wait on pending suspends */
> wait_queue_head_t suspend_wait;
> /** @suspend_pending: a suspend of the engine is pending */
> diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c b/drivers/gpu/drm/xe/xe_guc_submit.c
> index 0a41f5d04f6d..1b6f36b04cd1 100644
> --- a/drivers/gpu/drm/xe/xe_guc_submit.c
> +++ b/drivers/gpu/drm/xe/xe_guc_submit.c
> @@ -13,7 +13,10 @@
>
> #include <drm/drm_managed.h>
>
> +#include "regs/xe_guc_regs.h"
> #include "regs/xe_lrc_layout.h"
> +
> +#include "xe_bo.h"
> #include "xe_device.h"
> #include "xe_engine.h"
> #include "xe_force_wake.h"
> @@ -26,12 +29,22 @@
> #include "xe_lrc.h"
> #include "xe_macros.h"
> #include "xe_map.h"
> +#include "xe_mmio.h"
> #include "xe_mocs.h"
> #include "xe_ring_ops_types.h"
> #include "xe_sched_job.h"
> #include "xe_trace.h"
> #include "xe_vm.h"
>
> +#define HAS_GUC_MMIO_DB(xe) (IS_DGFX(xe) || GRAPHICS_VERx100(xe) >= 1250)
> +#define HAS_GUC_DIST_DB(xe) \
> + (GRAPHICS_VERx100(xe) >= 1200 && !HAS_GUC_MMIO_DB(xe))
> +
> +#define GUC_NUM_HW_DOORBELLS 256
> +
> +#define GUC_MMIO_DB_BAR_OFFSET SZ_4M
> +#define GUC_MMIO_DB_BAR_SIZE SZ_4M
> +
> static struct xe_gt *
> guc_to_gt(struct xe_guc *guc)
> {
> @@ -63,6 +76,7 @@ engine_to_guc(struct xe_engine *e)
> #define ENGINE_STATE_SUSPENDED (1 << 5)
> #define ENGINE_STATE_RESET (1 << 6)
> #define ENGINE_STATE_KILLED (1 << 7)
> +#define ENGINE_STATE_DB_REGISTERED (1 << 8)
>
> static bool engine_registered(struct xe_engine *e)
> {
> @@ -179,6 +193,16 @@ static void set_engine_killed(struct xe_engine *e)
> atomic_or(ENGINE_STATE_KILLED, &e->guc->state);
> }
>
> +static bool engine_doorbell_registered(struct xe_engine *e)
> +{
> + return atomic_read(&e->guc->state) & ENGINE_STATE_DB_REGISTERED;
> +}
> +
> +static void set_engine_doorbell_registered(struct xe_engine *e)
> +{
> + atomic_or(ENGINE_STATE_DB_REGISTERED, &e->guc->state);
> +}
> +
> static bool engine_killed_or_banned(struct xe_engine *e)
> {
> return engine_killed(e) || engine_banned(e);
> @@ -190,6 +214,7 @@ static void guc_submit_fini(struct drm_device *drm, void *arg)
>
> xa_destroy(&guc->submission_state.engine_lookup);
> ida_destroy(&guc->submission_state.guc_ids);
> + ida_destroy(&guc->submission_state.doorbell_ids);
> bitmap_free(guc->submission_state.guc_ids_bitmap);
> }
>
> @@ -230,6 +255,7 @@ int xe_guc_submit_init(struct xe_guc *guc)
> mutex_init(&guc->submission_state.lock);
> xa_init(&guc->submission_state.engine_lookup);
> ida_init(&guc->submission_state.guc_ids);
> + ida_init(&guc->submission_state.doorbell_ids);
>
> spin_lock_init(&guc->submission_state.suspend.lock);
> guc->submission_state.suspend.context = dma_fence_context_alloc(1);
> @@ -243,6 +269,237 @@ int xe_guc_submit_init(struct xe_guc *guc)
> return 0;
> }
>
> +int xe_guc_submit_init_post_hwconfig(struct xe_guc *guc)
> +{
> + if (HAS_GUC_DIST_DB(guc_to_xe(guc))) {
> + u32 distdbreg = xe_mmio_read32(guc_to_gt(guc),
> + DIST_DBS_POPULATED.reg);
> + u32 num_sqidi =
> + hweight32(distdbreg & SQIDIS_DOORBELL_EXIST_MASK);
> + u32 doorbells_per_sqidi =
> + ((distdbreg >> DOORBELLS_PER_SQIDI_SHIFT) &
> + DOORBELLS_PER_SQIDI_MASK) + 1;
> +
> + guc->submission_state.num_doorbells =
> + num_sqidi * doorbells_per_sqidi;
> + } else {
> + guc->submission_state.num_doorbells = GUC_NUM_HW_DOORBELLS;
> + }
> +
> + return 0;
> +}
> +
> +static bool alloc_doorbell_id(struct xe_guc *guc, struct xe_engine *e)
> +{
> + int ret;
> +
> + lockdep_assert_held(&guc->submission_state.lock);
> +
> + e->guc->doorbell_id = GUC_NUM_HW_DOORBELLS;
> + ret = ida_simple_get(&guc->submission_state.doorbell_ids, 0,
> + guc->submission_state.num_doorbells, GFP_NOWAIT);
> + if (ret < 0)
> + return false;
> +
> + e->guc->doorbell_id = ret;
> +
> + return true;
> +}
> +
> +static void release_doorbell_id(struct xe_guc *guc, struct xe_engine *e)
> +{
> + mutex_lock(&guc->submission_state.lock);
> + ida_simple_remove(&guc->submission_state.doorbell_ids,
> + e->guc->doorbell_id);
> + mutex_unlock(&guc->submission_state.lock);
> +
> + e->guc->doorbell_id = GUC_NUM_HW_DOORBELLS;
> +}
> +
> +static int allocate_doorbell(struct xe_guc *guc, u16 guc_id, u16 doorbell_id,
> + u64 gpa, u32 gtt_addr)
> +{
> + u32 action[] = {
> + XE_GUC_ACTION_ALLOCATE_DOORBELL,
> + guc_id,
> + doorbell_id,
> + lower_32_bits(gpa),
> + upper_32_bits(gpa),
> + gtt_addr
> + };
> +
> + return xe_guc_ct_send_block(&guc->ct, action, ARRAY_SIZE(action));
> +}
> +
> +static void deallocate_doorbell(struct xe_guc *guc, u16 guc_id)
> +{
> + u32 action[] = {
> + XE_GUC_ACTION_DEALLOCATE_DOORBELL,
> + guc_id
> + };
> +
> + xe_guc_ct_send(&guc->ct, action, ARRAY_SIZE(action), 0, 0);
> +}
> +
> +static bool has_doorbell(struct xe_engine *e)
> +{
> + return e->guc->doorbell_id != GUC_NUM_HW_DOORBELLS;
> +}
> +
> +#define doorbell_read(guc_, e_, field_) ({ \
> + struct iosys_map _vmap = (e_)->guc->doorbell_bo->vmap; \
> + iosys_map_incr(&_vmap, (e_)->guc->doorbell_offset); \
> + xe_map_rd_field(guc_to_xe((guc_)), &_vmap, 0, \
> + struct guc_doorbell_info, field_); \
> + })
> +#define doorbell_write(guc_, e_, field_, val_) ({ \
> + struct iosys_map _vmap = (e_)->guc->doorbell_bo->vmap; \
> + iosys_map_incr(&_vmap, (e_)->guc->doorbell_offset); \
> + xe_map_wr_field(guc_to_xe((guc_)), &_vmap, 0, \
> + struct guc_doorbell_info, field_, val_); \
> + })
> +
> +static void init_doorbell(struct xe_guc *guc, struct xe_engine *e)
> +{
> + struct xe_device *xe = guc_to_xe(guc);
> +
> + /* GuC does the initialization with distributed and MMIO doorbells */
> + if (!HAS_GUC_DIST_DB(xe) && !HAS_GUC_MMIO_DB(xe)) {
> + doorbell_write(guc, e, db_status, GUC_DOORBELL_ENABLED);
> + doorbell_write(guc, e, cookie, 0);
> + }
> +}
> +
> +static void fini_doorbell(struct xe_guc *guc, struct xe_engine *e)
> +{
> + if (!HAS_GUC_MMIO_DB(guc_to_xe(guc)) &&
> + xe_device_mem_access_ongoing(guc_to_xe(guc)))
> + doorbell_write(guc, e, db_status, GUC_DOORBELL_DISABLED);
> +}
> +
> +static void destroy_doorbell(struct xe_guc *guc, struct xe_engine *e)
> +{
> + if (has_doorbell(e)) {
> + release_doorbell_id(guc, e);
> + xe_bo_unpin_map_no_vm(e->guc->doorbell_bo);
> + }
> +}
> +
> +static void ring_memory_doorbell(struct xe_guc *guc, struct xe_engine *e)
> +{
> + u32 cookie;
> +
> + cookie = doorbell_read(guc, e, cookie);
> + doorbell_write(guc, e, cookie, cookie + 1 ?: cookie + 2);
> +
> + XE_WARN_ON(doorbell_read(guc, e, db_status) != GUC_DOORBELL_ENABLED);
> +}
> +
> +#define GUC_MMIO_DOORBELL_RING_ACK 0xACEDBEEF
> +#define GUC_MMIO_DOORBELL_RING_NACK 0xDEADBEEF
> +static void ring_mmio_doorbell(struct xe_guc *guc, u32 doorbell_offset)
> +{
> + u32 db_value;
> +
> + db_value = xe_mmio_read32(guc_to_gt(guc), GUC_MMIO_DB_BAR_OFFSET +
> + doorbell_offset);
> +
> + /*
> + * The read from the doorbell page will return ack/nack. We don't remove
> + * doorbells from active clients so we don't expect to ever get a nack.
> + * XXX: if doorbell is lost, re-acquire it?
> + */
> + XE_WARN_ON(db_value == GUC_MMIO_DOORBELL_RING_NACK);
> + XE_WARN_ON(db_value != GUC_MMIO_DOORBELL_RING_ACK);
> +}
> +
> +static void ring_doorbell(struct xe_guc *guc, struct xe_engine *e)
> +{
> + XE_BUG_ON(!has_doorbell(e));
> +
> + if (HAS_GUC_MMIO_DB(guc_to_xe(guc)))
> + ring_mmio_doorbell(guc, e->guc->doorbell_offset);
> + else
> + ring_memory_doorbell(guc, e);
> +
> + trace_xe_engine_ring_db(e);
> +}
> +
> +static void register_engine(struct xe_engine *e);
> +
> +static int create_doorbell(struct xe_guc *guc, struct xe_engine *e, bool init)
> +{
> + struct xe_gt *gt = guc_to_gt(guc);
> + struct xe_device *xe = gt_to_xe(gt);
> + u64 gpa;
> + u32 gtt_addr;
> + int ret;
> +
> + XE_BUG_ON(!has_doorbell(e));
> +
> + if (HAS_GUC_MMIO_DB(xe)) {
> + e->guc->doorbell_offset = PAGE_SIZE * e->guc->doorbell_id;
> + gpa = GUC_MMIO_DB_BAR_OFFSET + e->guc->doorbell_offset;
> + gtt_addr = 0;
> + } else {
> + struct xe_bo *bo;
> +
> + if (!e->guc->doorbell_bo) {
> + bo = xe_bo_create_pin_map(xe, gt, NULL, PAGE_SIZE,
> + ttm_bo_type_kernel,
> + XE_BO_CREATE_VRAM_IF_DGFX(gt) |
> + XE_BO_CREATE_GGTT_BIT);
> + if (IS_ERR(bo))
> + return PTR_ERR(bo);
> +
> + e->guc->doorbell_bo = bo;
> + } else {
> + bo = e->guc->doorbell_bo;
> + }
> +
> + init_doorbell(guc, e);
> + gpa = xe_bo_main_addr(bo, PAGE_SIZE);
> + gtt_addr = xe_bo_ggtt_addr(bo);
> + }
> +
> + if (init && e->flags & ENGINE_FLAG_KERNEL)
> + return 0;
> +
> + register_engine(e);
> + ret = allocate_doorbell(guc, e->guc->id, e->guc->doorbell_id, gpa,
> + gtt_addr);
> + if (ret < 0) {
> + fini_doorbell(guc, e);
> + return ret;
> + }
> +
> + /*
> + * In distributed doorbells, guc is returning the cacheline selected
> + * by HW as part of the 7bit data from the allocate doorbell command:
> + * bit [22] - Cacheline allocated
> + * bit [21:16] - Cacheline offset address
> + * (bit 21 must be zero, or our assumption of only using half a page is
> + * no longer correct).
> + */
> + if (HAS_GUC_DIST_DB(xe)) {
> + u32 dd_cacheline_info;
> +
> + XE_WARN_ON(!(ret & BIT(22)));
> + XE_WARN_ON(ret & BIT(21));
> +
> + dd_cacheline_info = FIELD_GET(GENMASK(21, 16), ret);
> + e->guc->doorbell_offset = dd_cacheline_info * cache_line_size();
> +
> + /* and verify db status was updated correctly by the guc fw */
> + XE_WARN_ON(doorbell_read(guc, e, db_status) !=
> + GUC_DOORBELL_ENABLED);
> + }
> +
> + set_engine_doorbell_registered(e);
> +
> + return 0;
> +}
> +
> static int alloc_guc_id(struct xe_guc *guc, struct xe_engine *e)
> {
> int ret;
> @@ -623,6 +880,7 @@ static void submit_engine(struct xe_engine *e)
> u32 num_g2h = 0;
> int len = 0;
> bool extra_submit = false;
> + bool enable = false;
>
> XE_BUG_ON(!engine_registered(e));
>
> @@ -642,6 +900,7 @@ static void submit_engine(struct xe_engine *e)
> num_g2h = 1;
> if (xe_engine_is_parallel(e))
> extra_submit = true;
> + enable = true;
>
> e->guc->resume_time = RESUME_PENDING;
> set_engine_pending_enable(e);
> @@ -653,7 +912,10 @@ static void submit_engine(struct xe_engine *e)
> trace_xe_engine_submit(e);
> }
>
> - xe_guc_ct_send(&guc->ct, action, len, g2h_len, num_g2h);
> + if (enable || !engine_doorbell_registered(e))
> + xe_guc_ct_send(&guc->ct, action, len, g2h_len, num_g2h);
> + else
> + ring_doorbell(guc, e);
>
> if (extra_submit) {
> len = 0;
> @@ -678,8 +940,17 @@ guc_engine_run_job(struct drm_sched_job *drm_job)
> trace_xe_sched_job_run(job);
>
> if (!engine_killed_or_banned(e) && !xe_sched_job_is_error(job)) {
> - if (!engine_registered(e))
> - register_engine(e);
> + if (!engine_registered(e)) {
> + if (has_doorbell(e)) {
> + int err = create_doorbell(engine_to_guc(e), e,
> + false);
> +
> + /* Not fatal, but let's warn */
> + XE_WARN_ON(err);
> + } else {
> + register_engine(e);
> + }
> + }
> if (!lr) /* Written in IOCTL */
> e->ring_ops->emit_job(job);
> submit_engine(e);
> @@ -722,6 +993,11 @@ static void disable_scheduling_deregister(struct xe_guc *guc,
> MAKE_SCHED_CONTEXT_ACTION(e, DISABLE);
> int ret;
>
> + if (has_doorbell(e)) {
> + fini_doorbell(guc, e);
> + deallocate_doorbell(guc, e->guc->id);
> + }
> +
> set_min_preemption_timeout(guc, e);
> smp_rmb();
> ret = wait_event_timeout(guc->ct.wq, !engine_pending_enable(e) ||
> @@ -958,6 +1234,7 @@ static void __guc_engine_fini_async(struct work_struct *w)
> cancel_work_sync(&ge->lr_tdr);
> if (e->flags & ENGINE_FLAG_PERSISTENT)
> xe_device_remove_persistent_engines(gt_to_xe(e->gt), e);
> + destroy_doorbell(guc, e);
> release_guc_id(guc, e);
> drm_sched_entity_fini(&ge->entity);
> drm_sched_fini(&ge->sched);
> @@ -1136,6 +1413,7 @@ static int guc_engine_init(struct xe_engine *e)
> struct xe_guc_engine *ge;
> long timeout;
> int err;
> + bool create_db = false;
>
> XE_BUG_ON(!xe_device_guc_submission_enabled(guc_to_xe(guc)));
>
> @@ -1177,8 +1455,17 @@ static int guc_engine_init(struct xe_engine *e)
> if (guc_read_stopped(guc))
> drm_sched_stop(sched, NULL);
>
> + create_db = alloc_doorbell_id(guc, e);
> +
> mutex_unlock(&guc->submission_state.lock);
>
> + if (create_db) {
> + /* Error isn't fatal as we don't need a doorbell */
> + err = create_doorbell(guc, e, true);
> + if (err)
> + release_doorbell_id(guc, e);
> + }
> +
> switch (e->class) {
> case XE_ENGINE_CLASS_RENDER:
> sprintf(e->name, "rcs%d", e->guc->id);
> @@ -1302,7 +1589,7 @@ static int guc_engine_set_job_timeout(struct xe_engine *e, u32 job_timeout_ms)
> {
> struct drm_gpu_scheduler *sched = &e->guc->sched;
>
> - XE_BUG_ON(engine_registered(e));
> + XE_BUG_ON(engine_registered(e) && !has_doorbell(e));
> XE_BUG_ON(engine_banned(e));
> XE_BUG_ON(engine_killed(e));
>
> diff --git a/drivers/gpu/drm/xe/xe_guc_submit.h b/drivers/gpu/drm/xe/xe_guc_submit.h
> index 8002734d6f24..bada6c02d6aa 100644
> --- a/drivers/gpu/drm/xe/xe_guc_submit.h
> +++ b/drivers/gpu/drm/xe/xe_guc_submit.h
> @@ -13,6 +13,7 @@ struct xe_engine;
> struct xe_guc;
>
> int xe_guc_submit_init(struct xe_guc *guc);
> +int xe_guc_submit_init_post_hwconfig(struct xe_guc *guc);
> void xe_guc_submit_print(struct xe_guc *guc, struct drm_printer *p);
>
> int xe_guc_submit_reset_prepare(struct xe_guc *guc);
> diff --git a/drivers/gpu/drm/xe/xe_guc_types.h b/drivers/gpu/drm/xe/xe_guc_types.h
> index ac7eec28934d..9ee4d572f4e0 100644
> --- a/drivers/gpu/drm/xe/xe_guc_types.h
> +++ b/drivers/gpu/drm/xe/xe_guc_types.h
> @@ -36,10 +36,14 @@ struct xe_guc {
> struct xarray engine_lookup;
> /** @guc_ids: used to allocate new guc_ids, single-lrc */
> struct ida guc_ids;
> + /** @doorbell_ids: use to allocate new doorbells */
> + struct ida doorbell_ids;
> /** @guc_ids_bitmap: used to allocate new guc_ids, multi-lrc */
> unsigned long *guc_ids_bitmap;
> /** @stopped: submissions are stopped */
> atomic_t stopped;
> + /** @num_doorbells: number of doorbels */
> + int num_doorbells;
> /** @lock: protects submission state */
> struct mutex lock;
> /** @suspend: suspend fence state */
> diff --git a/drivers/gpu/drm/xe/xe_trace.h b/drivers/gpu/drm/xe/xe_trace.h
> index 02861c26e145..38e9d7c6197b 100644
> --- a/drivers/gpu/drm/xe/xe_trace.h
> +++ b/drivers/gpu/drm/xe/xe_trace.h
> @@ -149,6 +149,11 @@ DEFINE_EVENT(xe_engine, xe_engine_submit,
> TP_ARGS(e)
> );
>
> +DEFINE_EVENT(xe_engine, xe_engine_ring_db,
> + TP_PROTO(struct xe_engine *e),
> + TP_ARGS(e)
> +);
> +
> DEFINE_EVENT(xe_engine, xe_engine_scheduling_enable,
> TP_PROTO(struct xe_engine *e),
> TP_ARGS(e)
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