[Intel-gfx] [PATCH 16/21] drm/i915/gem: Delay context creation
Daniel Vetter
daniel at ffwll.ch
Thu Apr 29 15:51:35 UTC 2021
Yeah this needs some text to explain what/why you're doing this, and maybe
some rough sketch of the locking design.
On Fri, Apr 23, 2021 at 05:31:26PM -0500, Jason Ekstrand wrote:
> Signed-off-by: Jason Ekstrand <jason at jlekstrand.net>
> ---
> drivers/gpu/drm/i915/gem/i915_gem_context.c | 657 ++++++++++++++++--
> drivers/gpu/drm/i915/gem/i915_gem_context.h | 3 +
> .../gpu/drm/i915/gem/i915_gem_context_types.h | 26 +
> .../gpu/drm/i915/gem/selftests/mock_context.c | 5 +-
> drivers/gpu/drm/i915/i915_drv.h | 17 +-
> 5 files changed, 648 insertions(+), 60 deletions(-)
So I think the patch split here is a bit unfortunate, because you're
adding the new vm/engine validation code for proto context here, but the
old stuff is only removed in the next patches that make vm/engines
immutable after first use.
I think a better split would be if this patch here only has all the
scaffolding. You already have the EOPNOTSUPP fallback (which I hope gets
removed), so moving the conversion entirely to later patches should be all
fine.
Or do I miss something?
I think the only concern I'm seeing is that bisectability might be a bit
lost, because we finalize the context in some cases in setparam. And if we
do the conversion in a different order than the one media uses for its
setparam, then later setparam might fail because the context is finalized
already. But also
- it's just bisectability of media functionality I think
- just check which order media calls CTX_SETPARAM and use that to do the
conversion
And we should be fine ... I think?
Some more thoughts below, but the proto ctx stuff itself looks fine.
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> index db9153e0f85a7..aa8e61211924f 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> @@ -193,8 +193,15 @@ static int validate_priority(struct drm_i915_private *i915,
>
> static void proto_context_close(struct i915_gem_proto_context *pc)
> {
> + int i;
> +
> if (pc->vm)
> i915_vm_put(pc->vm);
> + if (pc->user_engines) {
> + for (i = 0; i < pc->num_user_engines; i++)
> + kfree(pc->user_engines[i].siblings);
> + kfree(pc->user_engines);
> + }
> kfree(pc);
> }
>
> @@ -274,12 +281,417 @@ proto_context_create(struct drm_i915_private *i915, unsigned int flags)
> proto_context_set_persistence(i915, pc, true);
> pc->sched.priority = I915_PRIORITY_NORMAL;
>
> + pc->num_user_engines = -1;
> + pc->user_engines = NULL;
> +
> if (flags & I915_CONTEXT_CREATE_FLAGS_SINGLE_TIMELINE)
> pc->single_timeline = true;
>
> return pc;
> }
>
> +static int proto_context_register_locked(struct drm_i915_file_private *fpriv,
> + struct i915_gem_proto_context *pc,
> + u32 *id)
> +{
> + int ret;
> + void *old;
assert_lock_held just for consistency.
> +
> + ret = xa_alloc(&fpriv->context_xa, id, NULL, xa_limit_32b, GFP_KERNEL);
> + if (ret)
> + return ret;
> +
> + old = xa_store(&fpriv->proto_context_xa, *id, pc, GFP_KERNEL);
> + if (xa_is_err(old)) {
> + xa_erase(&fpriv->context_xa, *id);
> + return xa_err(old);
> + }
> + GEM_BUG_ON(old);
> +
> + return 0;
> +}
> +
> +static int proto_context_register(struct drm_i915_file_private *fpriv,
> + struct i915_gem_proto_context *pc,
> + u32 *id)
> +{
> + int ret;
> +
> + mutex_lock(&fpriv->proto_context_lock);
> + ret = proto_context_register_locked(fpriv, pc, id);
> + mutex_unlock(&fpriv->proto_context_lock);
> +
> + return ret;
> +}
> +
> +static int set_proto_ctx_vm(struct drm_i915_file_private *fpriv,
> + struct i915_gem_proto_context *pc,
> + const struct drm_i915_gem_context_param *args)
> +{
> + struct i915_address_space *vm;
> +
> + if (args->size)
> + return -EINVAL;
> +
> + if (!pc->vm)
> + return -ENODEV;
> +
> + if (upper_32_bits(args->value))
> + return -ENOENT;
> +
> + rcu_read_lock();
> + vm = xa_load(&fpriv->vm_xa, args->value);
> + if (vm && !kref_get_unless_zero(&vm->ref))
> + vm = NULL;
> + rcu_read_unlock();
> + if (!vm)
> + return -ENOENT;
> +
> + i915_vm_put(pc->vm);
> + pc->vm = vm;
> +
> + return 0;
> +}
> +
> +struct set_proto_ctx_engines {
> + struct drm_i915_private *i915;
> + unsigned num_engines;
> + struct i915_gem_proto_engine *engines;
> +};
> +
> +static int
> +set_proto_ctx_engines_balance(struct i915_user_extension __user *base,
> + void *data)
> +{
> + struct i915_context_engines_load_balance __user *ext =
> + container_of_user(base, typeof(*ext), base);
> + const struct set_proto_ctx_engines *set = data;
> + struct drm_i915_private *i915 = set->i915;
> + struct intel_engine_cs **siblings;
> + u16 num_siblings, idx;
> + unsigned int n;
> + int err;
> +
> + if (!HAS_EXECLISTS(i915))
> + return -ENODEV;
> +
> + if (intel_uc_uses_guc_submission(&i915->gt.uc))
> + return -ENODEV; /* not implement yet */
> +
> + if (get_user(idx, &ext->engine_index))
> + return -EFAULT;
> +
> + if (idx >= set->num_engines) {
> + drm_dbg(&i915->drm, "Invalid placement value, %d >= %d\n",
> + idx, set->num_engines);
> + return -EINVAL;
> + }
> +
> + idx = array_index_nospec(idx, set->num_engines);
> + if (set->engines[idx].type != I915_GEM_ENGINE_TYPE_INVALID) {
> + drm_dbg(&i915->drm,
> + "Invalid placement[%d], already occupied\n", idx);
> + return -EEXIST;
> + }
> +
> + if (get_user(num_siblings, &ext->num_siblings))
> + return -EFAULT;
> +
> + err = check_user_mbz(&ext->flags);
> + if (err)
> + return err;
> +
> + err = check_user_mbz(&ext->mbz64);
> + if (err)
> + return err;
> +
> + if (num_siblings == 0)
> + return 0;
> +
> + siblings = kmalloc_array(num_siblings, sizeof(*siblings), GFP_KERNEL);
> + if (!siblings)
> + return -ENOMEM;
> +
> + for (n = 0; n < num_siblings; n++) {
> + struct i915_engine_class_instance ci;
> +
> + if (copy_from_user(&ci, &ext->engines[n], sizeof(ci))) {
> + err = -EFAULT;
> + goto err_siblings;
> + }
> +
> + siblings[n] = intel_engine_lookup_user(i915,
> + ci.engine_class,
> + ci.engine_instance);
> + if (!siblings[n]) {
> + drm_dbg(&i915->drm,
> + "Invalid sibling[%d]: { class:%d, inst:%d }\n",
> + n, ci.engine_class, ci.engine_instance);
> + err = -EINVAL;
> + goto err_siblings;
> + }
> + }
> +
> + if (num_siblings == 1) {
> + set->engines[idx].type = I915_GEM_ENGINE_TYPE_PHYSICAL;
> + set->engines[idx].engine = siblings[0];
> + kfree(siblings);
> + } else {
> + set->engines[idx].type = I915_GEM_ENGINE_TYPE_BALANCED;
> + set->engines[idx].num_siblings = num_siblings;
> + set->engines[idx].siblings = siblings;
> + }
> +
> + return 0;
> +
> +err_siblings:
> + kfree(siblings);
> +
> + return err;
> +}
> +
> +static int
> +set_proto_ctx_engines_bond(struct i915_user_extension __user *base, void *data)
> +{
> + struct i915_context_engines_bond __user *ext =
> + container_of_user(base, typeof(*ext), base);
> + const struct set_proto_ctx_engines *set = data;
> + struct drm_i915_private *i915 = set->i915;
> + struct i915_engine_class_instance ci;
> + struct intel_engine_cs *master;
> + u16 idx, num_bonds;
> + int err, n;
> +
> + if (get_user(idx, &ext->virtual_index))
> + return -EFAULT;
> +
> + if (idx >= set->num_engines) {
> + drm_dbg(&i915->drm,
> + "Invalid index for virtual engine: %d >= %d\n",
> + idx, set->num_engines);
> + return -EINVAL;
> + }
> +
> + idx = array_index_nospec(idx, set->num_engines);
> + if (set->engines[idx].type == I915_GEM_ENGINE_TYPE_INVALID) {
> + drm_dbg(&i915->drm, "Invalid engine at %d\n", idx);
> + return -EINVAL;
> + }
> +
> + if (set->engines[idx].type != I915_GEM_ENGINE_TYPE_PHYSICAL) {
> + drm_dbg(&i915->drm,
> + "Bonding with virtual engines not allowed\n");
> + return -EINVAL;
> + }
> +
> + err = check_user_mbz(&ext->flags);
> + if (err)
> + return err;
> +
> + for (n = 0; n < ARRAY_SIZE(ext->mbz64); n++) {
> + err = check_user_mbz(&ext->mbz64[n]);
> + if (err)
> + return err;
> + }
> +
> + if (copy_from_user(&ci, &ext->master, sizeof(ci)))
> + return -EFAULT;
> +
> + master = intel_engine_lookup_user(i915,
> + ci.engine_class,
> + ci.engine_instance);
> + if (!master) {
> + drm_dbg(&i915->drm,
> + "Unrecognised master engine: { class:%u, instance:%u }\n",
> + ci.engine_class, ci.engine_instance);
> + return -EINVAL;
> + }
> +
> + if (get_user(num_bonds, &ext->num_bonds))
> + return -EFAULT;
> +
> + for (n = 0; n < num_bonds; n++) {
> + struct intel_engine_cs *bond;
> +
> + if (copy_from_user(&ci, &ext->engines[n], sizeof(ci)))
> + return -EFAULT;
> +
> + bond = intel_engine_lookup_user(i915,
> + ci.engine_class,
> + ci.engine_instance);
> + if (!bond) {
> + drm_dbg(&i915->drm,
> + "Unrecognised engine[%d] for bonding: { class:%d, instance: %d }\n",
> + n, ci.engine_class, ci.engine_instance);
> + return -EINVAL;
> + }
> + }
> +
> + return 0;
> +}
> +
> +static const i915_user_extension_fn set_proto_ctx_engines_extensions[] = {
> + [I915_CONTEXT_ENGINES_EXT_LOAD_BALANCE] = set_proto_ctx_engines_balance,
> + [I915_CONTEXT_ENGINES_EXT_BOND] = set_proto_ctx_engines_bond,
> +};
> +
> +static int set_proto_ctx_engines(struct drm_i915_file_private *fpriv,
> + struct i915_gem_proto_context *pc,
> + const struct drm_i915_gem_context_param *args)
> +{
> + struct drm_i915_private *i915 = fpriv->dev_priv;
> + struct set_proto_ctx_engines set = { .i915 = i915 };
> + struct i915_context_param_engines __user *user =
> + u64_to_user_ptr(args->value);
> + unsigned int n;
> + u64 extensions;
> + int err;
> +
> + if (!args->size) {
> + kfree(pc->user_engines);
> + pc->num_user_engines = -1;
> + pc->user_engines = NULL;
> + return 0;
> + }
> +
> + BUILD_BUG_ON(!IS_ALIGNED(sizeof(*user), sizeof(*user->engines)));
> + if (args->size < sizeof(*user) ||
> + !IS_ALIGNED(args->size, sizeof(*user->engines))) {
> + drm_dbg(&i915->drm, "Invalid size for engine array: %d\n",
> + args->size);
> + return -EINVAL;
> + }
> +
> + set.num_engines = (args->size - sizeof(*user)) / sizeof(*user->engines);
> + if (set.num_engines > I915_EXEC_RING_MASK + 1)
> + return -EINVAL;
> +
> + set.engines = kmalloc_array(set.num_engines, sizeof(*set.engines), GFP_KERNEL);
> + if (!set.engines)
> + return -ENOMEM;
> +
> + for (n = 0; n < set.num_engines; n++) {
> + struct i915_engine_class_instance ci;
> + struct intel_engine_cs *engine;
> +
> + if (copy_from_user(&ci, &user->engines[n], sizeof(ci))) {
> + kfree(set.engines);
> + return -EFAULT;
> + }
> +
> + memset(&set.engines[n], 0, sizeof(set.engines[n]));
> +
> + if (ci.engine_class == (u16)I915_ENGINE_CLASS_INVALID &&
> + ci.engine_instance == (u16)I915_ENGINE_CLASS_INVALID_NONE)
> + continue;
> +
> + engine = intel_engine_lookup_user(i915,
> + ci.engine_class,
> + ci.engine_instance);
> + if (!engine) {
> + drm_dbg(&i915->drm,
> + "Invalid engine[%d]: { class:%d, instance:%d }\n",
> + n, ci.engine_class, ci.engine_instance);
> + kfree(set.engines);
> + return -ENOENT;
> + }
> +
> + set.engines[n].type = I915_GEM_ENGINE_TYPE_PHYSICAL;
> + set.engines[n].engine = engine;
> + }
> +
> + err = -EFAULT;
> + if (!get_user(extensions, &user->extensions))
> + err = i915_user_extensions(u64_to_user_ptr(extensions),
> + set_proto_ctx_engines_extensions,
> + ARRAY_SIZE(set_proto_ctx_engines_extensions),
> + &set);
> + if (err) {
> + kfree(set.engines);
> + return err;
> + }
> +
> + kfree(pc->user_engines);
> + pc->num_user_engines = set.num_engines;
> + pc->user_engines = set.engines;
> +
> + return 0;
> +}
> +
> +static int set_proto_ctx_param(struct drm_i915_file_private *fpriv,
> + struct i915_gem_proto_context *pc,
> + struct drm_i915_gem_context_param *args)
> +{
> + int ret = 0;
> +
> + switch (args->param) {
> + case I915_CONTEXT_PARAM_NO_ERROR_CAPTURE:
> + if (args->size)
> + ret = -EINVAL;
> + else if (args->value)
> + set_bit(UCONTEXT_NO_ERROR_CAPTURE, &pc->user_flags);
Atomic bitops like in previous patches: Pls no :-)
> + else
> + clear_bit(UCONTEXT_NO_ERROR_CAPTURE, &pc->user_flags);
> + break;
> +
> + case I915_CONTEXT_PARAM_BANNABLE:
> + if (args->size)
> + ret = -EINVAL;
> + else if (!capable(CAP_SYS_ADMIN) && !args->value)
> + ret = -EPERM;
> + else if (args->value)
> + set_bit(UCONTEXT_BANNABLE, &pc->user_flags);
> + else
> + clear_bit(UCONTEXT_BANNABLE, &pc->user_flags);
> + break;
> +
> + case I915_CONTEXT_PARAM_RECOVERABLE:
> + if (args->size)
> + ret = -EINVAL;
> + else if (args->value)
> + set_bit(UCONTEXT_RECOVERABLE, &pc->user_flags);
> + else
> + clear_bit(UCONTEXT_RECOVERABLE, &pc->user_flags);
> + break;
> +
> + case I915_CONTEXT_PARAM_PRIORITY:
> + ret = validate_priority(fpriv->dev_priv, args);
> + if (!ret)
> + pc->sched.priority = args->value;
> + break;
> +
> + case I915_CONTEXT_PARAM_SSEU:
> + ret = -ENOTSUPP;
> + break;
> +
> + case I915_CONTEXT_PARAM_VM:
> + ret = set_proto_ctx_vm(fpriv, pc, args);
> + break;
> +
> + case I915_CONTEXT_PARAM_ENGINES:
> + ret = set_proto_ctx_engines(fpriv, pc, args);
> + break;
> +
> + case I915_CONTEXT_PARAM_PERSISTENCE:
> + if (args->size)
> + ret = -EINVAL;
> + else if (args->value)
> + set_bit(UCONTEXT_PERSISTENCE, &pc->user_flags);
> + else
> + clear_bit(UCONTEXT_PERSISTENCE, &pc->user_flags);
> + break;
> +
> + case I915_CONTEXT_PARAM_NO_ZEROMAP:
> + case I915_CONTEXT_PARAM_BAN_PERIOD:
> + case I915_CONTEXT_PARAM_RINGSIZE:
> + default:
> + ret = -EINVAL;
> + break;
> + }
> +
> + return ret;
> +}
> +
> static struct i915_address_space *
> context_get_vm_rcu(struct i915_gem_context *ctx)
> {
> @@ -450,6 +862,47 @@ static struct i915_gem_engines *default_engines(struct i915_gem_context *ctx)
> return e;
> }
>
> +static struct i915_gem_engines *user_engines(struct i915_gem_context *ctx,
> + unsigned int num_engines,
> + struct i915_gem_proto_engine *pe)
> +{
> + struct i915_gem_engines *e;
> + unsigned int n;
> +
> + e = alloc_engines(num_engines);
> + for (n = 0; n < num_engines; n++) {
> + struct intel_context *ce;
> +
> + switch (pe[n].type) {
> + case I915_GEM_ENGINE_TYPE_PHYSICAL:
> + ce = intel_context_create(pe[n].engine);
> + break;
> +
> + case I915_GEM_ENGINE_TYPE_BALANCED:
> + ce = intel_execlists_create_virtual(pe[n].siblings,
> + pe[n].num_siblings);
> + break;
> +
> + case I915_GEM_ENGINE_TYPE_INVALID:
> + default:
> + GEM_WARN_ON(pe[n].type != I915_GEM_ENGINE_TYPE_INVALID);
> + continue;
> + }
> +
> + if (IS_ERR(ce)) {
> + __free_engines(e, n);
> + return ERR_CAST(ce);
> + }
> +
> + intel_context_set_gem(ce, ctx);
> +
> + e->engines[n] = ce;
> + }
> + e->num_engines = num_engines;
> +
> + return e;
> +}
> +
> void i915_gem_context_release(struct kref *ref)
> {
> struct i915_gem_context *ctx = container_of(ref, typeof(*ctx), ref);
> @@ -890,6 +1343,24 @@ i915_gem_create_context(struct drm_i915_private *i915,
> mutex_unlock(&ctx->mutex);
> }
>
> + if (pc->num_user_engines >= 0) {
> + struct i915_gem_engines *engines;
> +
> + engines = user_engines(ctx, pc->num_user_engines,
> + pc->user_engines);
> + if (IS_ERR(engines)) {
> + context_close(ctx);
> + return ERR_CAST(engines);
> + }
> +
> + mutex_lock(&ctx->engines_mutex);
> + i915_gem_context_set_user_engines(ctx);
> + engines = rcu_replace_pointer(ctx->engines, engines, 1);
> + mutex_unlock(&ctx->engines_mutex);
> +
> + free_engines(engines);
> + }
> +
> if (pc->single_timeline) {
> ret = drm_syncobj_create(&ctx->syncobj,
> DRM_SYNCOBJ_CREATE_SIGNALED,
> @@ -916,12 +1387,12 @@ void i915_gem_init__contexts(struct drm_i915_private *i915)
> init_contexts(&i915->gem.contexts);
> }
>
> -static int gem_context_register(struct i915_gem_context *ctx,
> - struct drm_i915_file_private *fpriv,
> - u32 *id)
> +static void gem_context_register(struct i915_gem_context *ctx,
> + struct drm_i915_file_private *fpriv,
> + u32 id)
> {
> struct drm_i915_private *i915 = ctx->i915;
> - int ret;
> + void *old;
>
> ctx->file_priv = fpriv;
>
> @@ -930,19 +1401,12 @@ static int gem_context_register(struct i915_gem_context *ctx,
> current->comm, pid_nr(ctx->pid));
>
> /* And finally expose ourselves to userspace via the idr */
> - ret = xa_alloc(&fpriv->context_xa, id, ctx, xa_limit_32b, GFP_KERNEL);
> - if (ret)
> - goto err_pid;
> + old = xa_store(&fpriv->context_xa, id, ctx, GFP_KERNEL);
> + GEM_BUG_ON(old);
>
> spin_lock(&i915->gem.contexts.lock);
> list_add_tail(&ctx->link, &i915->gem.contexts.list);
> spin_unlock(&i915->gem.contexts.lock);
> -
> - return 0;
> -
> -err_pid:
> - put_pid(fetch_and_zero(&ctx->pid));
> - return ret;
> }
>
> int i915_gem_context_open(struct drm_i915_private *i915,
> @@ -952,9 +1416,12 @@ int i915_gem_context_open(struct drm_i915_private *i915,
> struct i915_gem_proto_context *pc;
> struct i915_gem_context *ctx;
> int err;
> - u32 id;
>
> - xa_init_flags(&file_priv->context_xa, XA_FLAGS_ALLOC);
> + mutex_init(&file_priv->proto_context_lock);
> + xa_init_flags(&file_priv->proto_context_xa, XA_FLAGS_ALLOC);
> +
> + /* 0 reserved for the default context */
> + xa_init_flags(&file_priv->context_xa, XA_FLAGS_ALLOC1);
>
> /* 0 reserved for invalid/unassigned ppgtt */
> xa_init_flags(&file_priv->vm_xa, XA_FLAGS_ALLOC1);
> @@ -972,28 +1439,31 @@ int i915_gem_context_open(struct drm_i915_private *i915,
> goto err;
> }
>
> - err = gem_context_register(ctx, file_priv, &id);
> - if (err < 0)
> - goto err_ctx;
> + gem_context_register(ctx, file_priv, 0);
>
> - GEM_BUG_ON(id);
> return 0;
>
> -err_ctx:
> - context_close(ctx);
> err:
> xa_destroy(&file_priv->vm_xa);
> xa_destroy(&file_priv->context_xa);
> + xa_destroy(&file_priv->proto_context_xa);
> + mutex_destroy(&file_priv->proto_context_lock);
> return err;
> }
>
> void i915_gem_context_close(struct drm_file *file)
> {
> struct drm_i915_file_private *file_priv = file->driver_priv;
> + struct i915_gem_proto_context *pc;
> struct i915_address_space *vm;
> struct i915_gem_context *ctx;
> unsigned long idx;
>
> + xa_for_each(&file_priv->proto_context_xa, idx, pc)
> + proto_context_close(pc);
> + xa_destroy(&file_priv->proto_context_xa);
> + mutex_destroy(&file_priv->proto_context_lock);
> +
> xa_for_each(&file_priv->context_xa, idx, ctx)
> context_close(ctx);
> xa_destroy(&file_priv->context_xa);
> @@ -1918,7 +2388,7 @@ static int ctx_setparam(struct drm_i915_file_private *fpriv,
> }
>
> struct create_ext {
> - struct i915_gem_context *ctx;
> + struct i915_gem_proto_context *pc;
> struct drm_i915_file_private *fpriv;
> };
>
> @@ -1933,7 +2403,7 @@ static int create_setparam(struct i915_user_extension __user *ext, void *data)
> if (local.param.ctx_id)
> return -EINVAL;
>
> - return ctx_setparam(arg->fpriv, arg->ctx, &local.param);
> + return set_proto_ctx_param(arg->fpriv, arg->pc, &local.param);
> }
>
> static int invalid_ext(struct i915_user_extension __user *ext, void *data)
> @@ -1951,12 +2421,71 @@ static bool client_is_banned(struct drm_i915_file_private *file_priv)
> return atomic_read(&file_priv->ban_score) >= I915_CLIENT_SCORE_BANNED;
> }
>
> +static inline struct i915_gem_context *
> +__context_lookup(struct drm_i915_file_private *file_priv, u32 id)
> +{
> + struct i915_gem_context *ctx;
> +
> + rcu_read_lock();
> + ctx = xa_load(&file_priv->context_xa, id);
> + if (ctx && !kref_get_unless_zero(&ctx->ref))
> + ctx = NULL;
> + rcu_read_unlock();
> +
> + return ctx;
> +}
> +
> +struct i915_gem_context *
> +lazy_create_context_locked(struct drm_i915_file_private *file_priv,
> + struct i915_gem_proto_context *pc, u32 id)
> +{
> + struct i915_gem_context *ctx;
> + void *old;
assert_lock_held is alwasy nice in all _locked functions. It entirely
compiles out without CONFIG_PROVE_LOCKING enabled.
> +
> + ctx = i915_gem_create_context(file_priv->dev_priv, pc);
I think we need a prep patch which changes the calling convetion of this
and anything it calls to only return a NULL pointer. Then
i915_gem_context_lookup below can return the ERR_PTR(-ENOMEM) below for
that case, and we know that we're never returning a wrong error pointer.
> + if (IS_ERR(ctx))
> + return ctx;
> +
> + gem_context_register(ctx, file_priv, id);
> +
> + old = xa_erase(&file_priv->proto_context_xa, id);
> + GEM_BUG_ON(old != pc);
> + proto_context_close(pc);
> +
> + /* One for the xarray and one for the caller */
> + return i915_gem_context_get(ctx);
> +}
> +
> +struct i915_gem_context *
> +i915_gem_context_lookup(struct drm_i915_file_private *file_priv, u32 id)
> +{
> + struct i915_gem_proto_context *pc;
> + struct i915_gem_context *ctx;
> +
> + ctx = __context_lookup(file_priv, id);
> + if (ctx)
> + return ctx;
> +
> + mutex_lock(&file_priv->proto_context_lock);
> + /* Try one more time under the lock */
> + ctx = __context_lookup(file_priv, id);
> + if (!ctx) {
> + pc = xa_load(&file_priv->proto_context_xa, id);
> + if (!pc)
> + ctx = ERR_PTR(-ENOENT);
> + else
> + ctx = lazy_create_context_locked(file_priv, pc, id);
> + }
> + mutex_unlock(&file_priv->proto_context_lock);
> +
> + return ctx;
> +}
> +
> int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
> struct drm_file *file)
> {
> struct drm_i915_private *i915 = to_i915(dev);
> struct drm_i915_gem_context_create_ext *args = data;
> - struct i915_gem_proto_context *pc;
> struct create_ext ext_data;
> int ret;
> u32 id;
> @@ -1979,14 +2508,9 @@ int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
> return -EIO;
> }
>
> - pc = proto_context_create(i915, args->flags);
> - if (IS_ERR(pc))
> - return PTR_ERR(pc);
> -
> - ext_data.ctx = i915_gem_create_context(i915, pc);
> - proto_context_close(pc);
> - if (IS_ERR(ext_data.ctx))
> - return PTR_ERR(ext_data.ctx);
> + ext_data.pc = proto_context_create(i915, args->flags);
> + if (IS_ERR(ext_data.pc))
> + return PTR_ERR(ext_data.pc);
>
> if (args->flags & I915_CONTEXT_CREATE_FLAGS_USE_EXTENSIONS) {
> ret = i915_user_extensions(u64_to_user_ptr(args->extensions),
> @@ -1994,20 +2518,20 @@ int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
> ARRAY_SIZE(create_extensions),
> &ext_data);
> if (ret)
> - goto err_ctx;
> + goto err_pc;
> }
>
> - ret = gem_context_register(ext_data.ctx, ext_data.fpriv, &id);
> + ret = proto_context_register(ext_data.fpriv, ext_data.pc, &id);
> if (ret < 0)
> - goto err_ctx;
> + goto err_pc;
>
> args->ctx_id = id;
> drm_dbg(&i915->drm, "HW context %d created\n", args->ctx_id);
>
> return 0;
>
> -err_ctx:
> - context_close(ext_data.ctx);
> +err_pc:
> + proto_context_close(ext_data.pc);
> return ret;
> }
>
> @@ -2016,6 +2540,7 @@ int i915_gem_context_destroy_ioctl(struct drm_device *dev, void *data,
> {
> struct drm_i915_gem_context_destroy *args = data;
> struct drm_i915_file_private *file_priv = file->driver_priv;
> + struct i915_gem_proto_context *pc;
> struct i915_gem_context *ctx;
>
> if (args->pad != 0)
> @@ -2024,11 +2549,21 @@ int i915_gem_context_destroy_ioctl(struct drm_device *dev, void *data,
> if (!args->ctx_id)
> return -ENOENT;
>
> + mutex_lock(&file_priv->proto_context_lock);
> ctx = xa_erase(&file_priv->context_xa, args->ctx_id);
> - if (!ctx)
> + pc = xa_erase(&file_priv->proto_context_xa, args->ctx_id);
> + mutex_unlock(&file_priv->proto_context_lock);
> +
> + if (!ctx && !pc)
> return -ENOENT;
> + GEM_WARN_ON(ctx && pc);
> +
> + if (pc)
> + proto_context_close(pc);
> +
> + if (ctx)
> + context_close(ctx);
>
> - context_close(ctx);
> return 0;
> }
>
> @@ -2161,16 +2696,48 @@ int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
> {
> struct drm_i915_file_private *file_priv = file->driver_priv;
> struct drm_i915_gem_context_param *args = data;
> + struct i915_gem_proto_context *pc;
> struct i915_gem_context *ctx;
> - int ret;
> + int ret = 0;
>
> - ctx = i915_gem_context_lookup(file_priv, args->ctx_id);
> - if (IS_ERR(ctx))
> - return PTR_ERR(ctx);
> + ctx = __context_lookup(file_priv, args->ctx_id);
> + if (ctx)
> + goto set_ctx_param;
>
> - ret = ctx_setparam(file_priv, ctx, args);
> + mutex_lock(&file_priv->proto_context_lock);
> + ctx = __context_lookup(file_priv, args->ctx_id);
> + if (ctx)
> + goto unlock;
> +
> + pc = xa_load(&file_priv->proto_context_xa, args->ctx_id);
> + if (!pc) {
> + ret = -ENOENT;
> + goto unlock;
> + }
> +
> + ret = set_proto_ctx_param(file_priv, pc, args);
I think we should have a FIXME here of not allowing this on some future
platforms because just use CTX_CREATE_EXT.
> + if (ret == -ENOTSUPP) {
> + /* Some params, specifically SSEU, can only be set on fully
I think this needs a FIXME: that this only holds during the conversion?
Otherwise we kinda have a bit a problem me thinks ...
> + * created contexts.
> + */
> + ret = 0;
> + ctx = lazy_create_context_locked(file_priv, pc, args->ctx_id);
> + if (IS_ERR(ctx)) {
> + ret = PTR_ERR(ctx);
> + ctx = NULL;
> + }
> + }
> +
> +unlock:
> + mutex_unlock(&file_priv->proto_context_lock);
> +
> +set_ctx_param:
> + if (!ret && ctx)
> + ret = ctx_setparam(file_priv, ctx, args);
> +
> + if (ctx)
> + i915_gem_context_put(ctx);
>
> - i915_gem_context_put(ctx);
> return ret;
> }
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.h b/drivers/gpu/drm/i915/gem/i915_gem_context.h
> index b5c908f3f4f22..20411db84914a 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.h
> @@ -133,6 +133,9 @@ int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
> 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)
> {
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h
> index a42c429f94577..067ea3030ac91 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h
> @@ -46,6 +46,26 @@ struct i915_gem_engines_iter {
> const struct i915_gem_engines *engines;
> };
>
> +enum i915_gem_engine_type {
> + I915_GEM_ENGINE_TYPE_INVALID = 0,
> + I915_GEM_ENGINE_TYPE_PHYSICAL,
> + I915_GEM_ENGINE_TYPE_BALANCED,
> +};
> +
Some kerneldoc missing?
> +struct i915_gem_proto_engine {
> + /** @type: Type of this engine */
> + enum i915_gem_engine_type type;
> +
> + /** @num_siblings: Engine, for physical */
> + struct intel_engine_cs *engine;
> +
> + /** @num_siblings: Number of balanced siblings */
> + unsigned int num_siblings;
> +
> + /** @num_siblings: Balanced siblings */
> + struct intel_engine_cs **siblings;
I guess you're stuffing both balanced and siblings into one?
> +};
> +
> /**
> * struct i915_gem_proto_context - prototype context
> *
> @@ -64,6 +84,12 @@ struct i915_gem_proto_context {
> /** @sched: See i915_gem_context::sched */
> struct i915_sched_attr sched;
>
> + /** @num_user_engines: Number of user-specified engines or -1 */
> + int num_user_engines;
> +
> + /** @num_user_engines: User-specified engines */
> + struct i915_gem_proto_engine *user_engines;
> +
> bool single_timeline;
> };
>
> diff --git a/drivers/gpu/drm/i915/gem/selftests/mock_context.c b/drivers/gpu/drm/i915/gem/selftests/mock_context.c
> index e0f512ef7f3c6..32cf2103828f9 100644
> --- a/drivers/gpu/drm/i915/gem/selftests/mock_context.c
> +++ b/drivers/gpu/drm/i915/gem/selftests/mock_context.c
> @@ -80,6 +80,7 @@ void mock_init_contexts(struct drm_i915_private *i915)
> struct i915_gem_context *
> live_context(struct drm_i915_private *i915, struct file *file)
> {
> + struct drm_i915_file_private *fpriv = to_drm_file(file)->driver_priv;
> struct i915_gem_proto_context *pc;
> struct i915_gem_context *ctx;
> int err;
> @@ -96,10 +97,12 @@ live_context(struct drm_i915_private *i915, struct file *file)
>
> i915_gem_context_set_no_error_capture(ctx);
>
> - err = gem_context_register(ctx, to_drm_file(file)->driver_priv, &id);
> + err = xa_alloc(&fpriv->context_xa, &id, NULL, xa_limit_32b, GFP_KERNEL);
> if (err < 0)
> goto err_ctx;
>
> + gem_context_register(ctx, fpriv, id);
> +
> return ctx;
>
> err_ctx:
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 004ed0e59c999..365c042529d72 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -200,6 +200,9 @@ struct drm_i915_file_private {
> struct rcu_head rcu;
> };
>
> + struct mutex proto_context_lock;
> + struct xarray proto_context_xa;
Kerneldoc here please. Ideally also for the context_xa below (but maybe
that's for later).
Also please add a hint to the proto context struct that it's all fully
protected by proto_context_lock above and is never visible outside of
that.
> +
> struct xarray context_xa;
> struct xarray vm_xa;
>
> @@ -1840,20 +1843,6 @@ struct drm_gem_object *i915_gem_prime_import(struct drm_device *dev,
>
> struct dma_buf *i915_gem_prime_export(struct drm_gem_object *gem_obj, int flags);
>
> -static inline struct i915_gem_context *
> -i915_gem_context_lookup(struct drm_i915_file_private *file_priv, u32 id)
> -{
> - struct i915_gem_context *ctx;
> -
> - rcu_read_lock();
> - ctx = xa_load(&file_priv->context_xa, id);
> - if (ctx && !kref_get_unless_zero(&ctx->ref))
> - ctx = NULL;
> - rcu_read_unlock();
> -
> - return ctx ? ctx : ERR_PTR(-ENOENT);
> -}
> -
> /* i915_gem_evict.c */
> int __must_check i915_gem_evict_something(struct i915_address_space *vm,
> u64 min_size, u64 alignment,
I think I'll check details when I'm not getting distracted by the
vm/engines validation code that I think shouldn't be here :-)
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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