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drm/i915/guc: Fill preempt context once at init time

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Since we're inhibiting context save of preempt context, we're no longer
tracking the position of HEAD/TAIL. With GuC, we're adding a new
breadcrumb for each preemption, which means that the HW will do more and
more breadcrumb writes. Eventually the ring is filled, and we're
submitting the preemption context with HEAD==TAIL==0, which won't result
in breadcrumb write, but will trigger hangcheck instead.
Instead of writing a new preempt breadcrumb for each preemption, let's
just fill the ring once at init time (which also saves a couple of
instructions in the tasklet).

v2: Assert that context save restore is inhibited, don't assert on ring
    alignment. (Chris)
v3: Cleanup checkpatch.

Fixes: 517aaffe0c ("drm/i915/execlists: Inhibit context save/restore for the fake preempt context")
Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180226163800.21745-1-michal.winiarski@intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
This commit is contained in:
Michał Winiarski 2018-02-26 17:37:59 +01:00 committed by Chris Wilson
parent ba1c06a572
commit 5028a4fb7d
1 changed files with 69 additions and 27 deletions
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96
drivers/gpu/drm/i915/intel_guc_submission.c
View file

@ -26,8 +26,14 @@
#include <trace/events/dma_fence.h>
#include "intel_guc_submission.h"
#include "intel_lrc_reg.h"
#include "i915_drv.h"
#define GUC_PREEMPT_FINISHED 0x1
#define GUC_PREEMPT_BREADCRUMB_DWORDS 0x8
#define GUC_PREEMPT_BREADCRUMB_BYTES \
(sizeof(u32) * GUC_PREEMPT_BREADCRUMB_DWORDS)
/**
* DOC: GuC-based command submission
*
@ -535,8 +541,6 @@ static void flush_ggtt_writes(struct i915_vma *vma)
POSTING_READ_FW(GUC_STATUS);
}
#define GUC_PREEMPT_FINISHED 0x1
#define GUC_PREEMPT_BREADCRUMB_DWORDS 0x8
static void inject_preempt_context(struct work_struct *work)
{
struct guc_preempt_work *preempt_work =
@ -546,37 +550,17 @@ static void inject_preempt_context(struct work_struct *work)
preempt_work[engine->id]);
struct intel_guc_client *client = guc->preempt_client;
struct guc_stage_desc *stage_desc = __get_stage_desc(client);
struct intel_ring *ring = client->owner->engine[engine->id].ring;
u32 ctx_desc = lower_32_bits(intel_lr_context_descriptor(client->owner,
engine));
u32 *cs = ring->vaddr + ring->tail;
u32 data[7];
if (engine->id == RCS) {
cs = gen8_emit_ggtt_write_rcs(cs, GUC_PREEMPT_FINISHED,
intel_hws_preempt_done_address(engine));
} else {
cs = gen8_emit_ggtt_write(cs, GUC_PREEMPT_FINISHED,
intel_hws_preempt_done_address(engine));
*cs++ = MI_NOOP;
*cs++ = MI_NOOP;
}
*cs++ = MI_USER_INTERRUPT;
*cs++ = MI_NOOP;
GEM_BUG_ON(!IS_ALIGNED(ring->size,
GUC_PREEMPT_BREADCRUMB_DWORDS * sizeof(u32)));
GEM_BUG_ON((void *)cs - (ring->vaddr + ring->tail) !=
GUC_PREEMPT_BREADCRUMB_DWORDS * sizeof(u32));
ring->tail += GUC_PREEMPT_BREADCRUMB_DWORDS * sizeof(u32);
ring->tail &= (ring->size - 1);
flush_ggtt_writes(ring->vma);
/*
* The ring contains commands to write GUC_PREEMPT_FINISHED into HWSP.
* See guc_fill_preempt_context().
*/
spin_lock_irq(&client->wq_lock);
guc_wq_item_append(client, engine->guc_id, ctx_desc,
ring->tail / sizeof(u64), 0);
GUC_PREEMPT_BREADCRUMB_BYTES / sizeof(u64), 0);
spin_unlock_irq(&client->wq_lock);
/*
@ -972,6 +956,62 @@ static void guc_client_free(struct intel_guc_client *client)
kfree(client);
}
static inline bool ctx_save_restore_disabled(struct intel_context *ce)
{
u32 sr = ce->lrc_reg_state[CTX_CONTEXT_CONTROL + 1];
#define SR_DISABLED \
_MASKED_BIT_ENABLE(CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT | \
CTX_CTRL_ENGINE_CTX_SAVE_INHIBIT)
return (sr & SR_DISABLED) == SR_DISABLED;
#undef SR_DISABLED
}
static void guc_fill_preempt_context(struct intel_guc *guc)
{
struct drm_i915_private *dev_priv = guc_to_i915(guc);
struct intel_guc_client *client = guc->preempt_client;
struct intel_engine_cs *engine;
enum intel_engine_id id;
for_each_engine(engine, dev_priv, id) {
struct intel_context *ce = &client->owner->engine[id];
u32 addr = intel_hws_preempt_done_address(engine);
u32 *cs;
GEM_BUG_ON(!ce->pin_count);
/*
* We rely on this context image *not* being saved after
* preemption. This ensures that the RING_HEAD / RING_TAIL
* remain pointing at initial values forever.
*/
GEM_BUG_ON(!ctx_save_restore_disabled(ce));
cs = ce->ring->vaddr;
if (id == RCS) {
cs = gen8_emit_ggtt_write_rcs(cs,
GUC_PREEMPT_FINISHED,
addr);
} else {
cs = gen8_emit_ggtt_write(cs,
GUC_PREEMPT_FINISHED,
addr);
*cs++ = MI_NOOP;
*cs++ = MI_NOOP;
}
*cs++ = MI_USER_INTERRUPT;
*cs++ = MI_NOOP;
GEM_BUG_ON((void *)cs - ce->ring->vaddr !=
GUC_PREEMPT_BREADCRUMB_BYTES);
flush_ggtt_writes(ce->ring->vma);
}
}
static int guc_clients_create(struct intel_guc *guc)
{
struct drm_i915_private *dev_priv = guc_to_i915(guc);
@ -1002,6 +1042,8 @@ static int guc_clients_create(struct intel_guc *guc)
return PTR_ERR(client);
}
guc->preempt_client = client;
guc_fill_preempt_context(guc);
}
return 0;