linux-stable/drivers/gpu/drm/i915/gem/i915_gem_context.h
Jason Ekstrand a4c1cdd34e drm/i915/gem: Delay context creation (v3)
The current context uAPI allows for two methods of setting context
parameters: SET_CONTEXT_PARAM and CONTEXT_CREATE_EXT_SETPARAM.  The
former is allowed to be called at any time while the later happens as
part of GEM_CONTEXT_CREATE.  Currently, everything settable via one is
settable via the other.  While some params are fairly simple and setting
them on a live context is harmless such as the context priority, others
are far trickier such as the VM or the set of engines.  In order to swap
out the VM, for instance, we have to delay until all current in-flight
work is complete, swap in the new VM, and then continue.  This leads to
a plethora of potential race conditions we'd really rather avoid.

In previous patches, we added a i915_gem_proto_context struct which is
capable of storing and tracking all such create parameters.  This commit
delays the creation of the actual context until after the client is done
configuring it with SET_CONTEXT_PARAM.  From the perspective of the
client, it has the same u32 context ID the whole time.  From the
perspective of i915, however, it's an i915_gem_proto_context right up
until the point where we attempt to do something which the proto-context
can't handle.  Then the real context gets created.

This is accomplished via a little xarray dance.  When GEM_CONTEXT_CREATE
is called, we create a proto-context, reserve a slot in context_xa but
leave it NULL, the proto-context in the corresponding slot in
proto_context_xa.  Then, whenever we go to look up a context, we first
check context_xa.  If it's there, we return the i915_gem_context and
we're done.  If it's not, we look in proto_context_xa and, if we find it
there, we create the actual context and kill the proto-context.

In order for this dance to work properly, everything which ever touches
a proto-context is guarded by drm_i915_file_private::proto_context_lock,
including context creation.  Yes, this means context creation now takes
a giant global lock but it can't really be helped and that should never
be on any driver's fast-path anyway.

v2 (Daniel Vetter):
 - Commit message grammatical fixes.
 - Use WARN_ON instead of GEM_BUG_ON
 - Rename lazy_create_context_locked to finalize_create_context_locked
 - Rework the control-flow logic in the setparam ioctl
 - Better documentation all around

v3 (kernel test robot):
 - Make finalize_create_context_locked static

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210708154835.528166-25-jason@jlekstrand.net
2021-07-08 19:48:52 +02:00

234 lines
6.2 KiB
C

/*
* SPDX-License-Identifier: MIT
*
* Copyright © 2016 Intel Corporation
*/
#ifndef __I915_GEM_CONTEXT_H__
#define __I915_GEM_CONTEXT_H__
#include "i915_gem_context_types.h"
#include "gt/intel_context.h"
#include "i915_drv.h"
#include "i915_gem.h"
#include "i915_scheduler.h"
#include "intel_device_info.h"
struct drm_device;
struct drm_file;
static inline bool i915_gem_context_is_closed(const struct i915_gem_context *ctx)
{
return test_bit(CONTEXT_CLOSED, &ctx->flags);
}
static inline void i915_gem_context_set_closed(struct i915_gem_context *ctx)
{
GEM_BUG_ON(i915_gem_context_is_closed(ctx));
set_bit(CONTEXT_CLOSED, &ctx->flags);
}
static inline bool i915_gem_context_no_error_capture(const struct i915_gem_context *ctx)
{
return test_bit(UCONTEXT_NO_ERROR_CAPTURE, &ctx->user_flags);
}
static inline void i915_gem_context_set_no_error_capture(struct i915_gem_context *ctx)
{
set_bit(UCONTEXT_NO_ERROR_CAPTURE, &ctx->user_flags);
}
static inline void i915_gem_context_clear_no_error_capture(struct i915_gem_context *ctx)
{
clear_bit(UCONTEXT_NO_ERROR_CAPTURE, &ctx->user_flags);
}
static inline bool i915_gem_context_is_bannable(const struct i915_gem_context *ctx)
{
return test_bit(UCONTEXT_BANNABLE, &ctx->user_flags);
}
static inline void i915_gem_context_set_bannable(struct i915_gem_context *ctx)
{
set_bit(UCONTEXT_BANNABLE, &ctx->user_flags);
}
static inline void i915_gem_context_clear_bannable(struct i915_gem_context *ctx)
{
clear_bit(UCONTEXT_BANNABLE, &ctx->user_flags);
}
static inline bool i915_gem_context_is_recoverable(const struct i915_gem_context *ctx)
{
return test_bit(UCONTEXT_RECOVERABLE, &ctx->user_flags);
}
static inline void i915_gem_context_set_recoverable(struct i915_gem_context *ctx)
{
set_bit(UCONTEXT_RECOVERABLE, &ctx->user_flags);
}
static inline void i915_gem_context_clear_recoverable(struct i915_gem_context *ctx)
{
clear_bit(UCONTEXT_RECOVERABLE, &ctx->user_flags);
}
static inline bool i915_gem_context_is_persistent(const struct i915_gem_context *ctx)
{
return test_bit(UCONTEXT_PERSISTENCE, &ctx->user_flags);
}
static inline void i915_gem_context_set_persistence(struct i915_gem_context *ctx)
{
set_bit(UCONTEXT_PERSISTENCE, &ctx->user_flags);
}
static inline void i915_gem_context_clear_persistence(struct i915_gem_context *ctx)
{
clear_bit(UCONTEXT_PERSISTENCE, &ctx->user_flags);
}
static inline bool
i915_gem_context_user_engines(const struct i915_gem_context *ctx)
{
return test_bit(CONTEXT_USER_ENGINES, &ctx->flags);
}
static inline void
i915_gem_context_set_user_engines(struct i915_gem_context *ctx)
{
set_bit(CONTEXT_USER_ENGINES, &ctx->flags);
}
static inline void
i915_gem_context_clear_user_engines(struct i915_gem_context *ctx)
{
clear_bit(CONTEXT_USER_ENGINES, &ctx->flags);
}
/* i915_gem_context.c */
void i915_gem_init__contexts(struct drm_i915_private *i915);
int i915_gem_context_open(struct drm_i915_private *i915,
struct drm_file *file);
void i915_gem_context_close(struct drm_file *file);
void i915_gem_context_release(struct kref *ctx_ref);
int i915_gem_vm_create_ioctl(struct drm_device *dev, void *data,
struct drm_file *file);
int i915_gem_vm_destroy_ioctl(struct drm_device *dev, void *data,
struct drm_file *file);
int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
struct drm_file *file);
int i915_gem_context_destroy_ioctl(struct drm_device *dev, void *data,
struct drm_file *file);
int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data,
struct drm_file *file_priv);
int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
struct drm_file *file_priv);
int i915_gem_context_reset_stats_ioctl(struct drm_device *dev, void *data,
struct drm_file *file);
struct i915_gem_context *
i915_gem_context_lookup(struct drm_i915_file_private *file_priv, u32 id);
static inline struct i915_gem_context *
i915_gem_context_get(struct i915_gem_context *ctx)
{
kref_get(&ctx->ref);
return ctx;
}
static inline void i915_gem_context_put(struct i915_gem_context *ctx)
{
kref_put(&ctx->ref, i915_gem_context_release);
}
static inline struct i915_address_space *
i915_gem_context_vm(struct i915_gem_context *ctx)
{
return rcu_dereference_protected(ctx->vm, lockdep_is_held(&ctx->mutex));
}
static inline struct i915_address_space *
i915_gem_context_get_vm_rcu(struct i915_gem_context *ctx)
{
struct i915_address_space *vm;
rcu_read_lock();
vm = rcu_dereference(ctx->vm);
if (!vm)
vm = &ctx->i915->ggtt.vm;
vm = i915_vm_get(vm);
rcu_read_unlock();
return vm;
}
static inline struct i915_gem_engines *
i915_gem_context_engines(struct i915_gem_context *ctx)
{
return rcu_dereference_protected(ctx->engines,
lockdep_is_held(&ctx->engines_mutex));
}
static inline struct i915_gem_engines *
i915_gem_context_lock_engines(struct i915_gem_context *ctx)
__acquires(&ctx->engines_mutex)
{
mutex_lock(&ctx->engines_mutex);
return i915_gem_context_engines(ctx);
}
static inline void
i915_gem_context_unlock_engines(struct i915_gem_context *ctx)
__releases(&ctx->engines_mutex)
{
mutex_unlock(&ctx->engines_mutex);
}
static inline struct intel_context *
i915_gem_context_get_engine(struct i915_gem_context *ctx, unsigned int idx)
{
struct intel_context *ce;
rcu_read_lock(); {
struct i915_gem_engines *e = rcu_dereference(ctx->engines);
if (unlikely(!e)) /* context was closed! */
ce = ERR_PTR(-ENOENT);
else if (likely(idx < e->num_engines && e->engines[idx]))
ce = intel_context_get(e->engines[idx]);
else
ce = ERR_PTR(-EINVAL);
} rcu_read_unlock();
return ce;
}
static inline void
i915_gem_engines_iter_init(struct i915_gem_engines_iter *it,
struct i915_gem_engines *engines)
{
it->engines = engines;
it->idx = 0;
}
struct intel_context *
i915_gem_engines_iter_next(struct i915_gem_engines_iter *it);
#define for_each_gem_engine(ce, engines, it) \
for (i915_gem_engines_iter_init(&(it), (engines)); \
((ce) = i915_gem_engines_iter_next(&(it)));)
struct i915_lut_handle *i915_lut_handle_alloc(void);
void i915_lut_handle_free(struct i915_lut_handle *lut);
int i915_gem_user_to_context_sseu(struct intel_gt *gt,
const struct drm_i915_gem_context_param_sseu *user,
struct intel_sseu *context);
#endif /* !__I915_GEM_CONTEXT_H__ */