[RFC] drm/i915: Support replaying GPU hangs with captured context image
Rodrigo Vivi
rodrigo.vivi at intel.com
Tue Feb 20 22:50:27 UTC 2024
On Tue, Feb 13, 2024 at 01:14:34PM +0000, Tvrtko Ursulin wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
>
> When debugging GPU hangs Mesa developers are finding it useful to replay
> the captured error state against the simulator. But due various simulator
> limitations which prevent replicating all hangs, one step further is being
> able to replay against a real GPU.
>
> This is almost doable today with the missing part being able to upload the
> captured context image into the driver state prior to executing the
> uploaded hanging batch and all the buffers.
>
> To enable this last part we add a new context parameter called
> I915_CONTEXT_PARAM_CONTEXT_IMAGE. It follows the existing SSEU
> configuration pattern of being able to select which context to apply
> against, paired with the actual image and its size.
>
> Since this is adding a new concept of debug only uapi, we hide it behind
> a new kconfig option and also require activation with a module parameter.
> Together with a warning banner printed at driver load, all those combined
> should be sufficient to guard against inadvertently enabling the feature.
>
> In terms of implementation the only trivial change is shadowing of the
> default state from engine to context. We also allow the legacy context
> set param to be used since that removes the need to record the per context
> data in the proto context, while still allowing flexibility of specifying
> context images for any context.
>
> Mesa MR using the uapi can be seen at:
> https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27594
I just wonder if it would be better to split the default_state in a separate
patch.... but from what I could see it looks correct.
Also, I have to say that this approach is nice, clean and well protected.
And much simpler then I imagined when I saw the idea around.
Feel free to use:
Reviewed-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
>
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Cc: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
> Cc: Carlos Santa <carlos.santa at intel.com>
> ---
> drivers/gpu/drm/i915/Kconfig.debug | 17 +++
> drivers/gpu/drm/i915/gem/i915_gem_context.c | 106 ++++++++++++++++++
> drivers/gpu/drm/i915/gt/intel_context.c | 2 +
> drivers/gpu/drm/i915/gt/intel_context.h | 22 ++++
> drivers/gpu/drm/i915/gt/intel_context_types.h | 3 +
> drivers/gpu/drm/i915/gt/intel_lrc.c | 8 +-
> .../gpu/drm/i915/gt/intel_ring_submission.c | 8 +-
> drivers/gpu/drm/i915/i915_params.c | 5 +
> drivers/gpu/drm/i915/i915_params.h | 3 +-
> include/uapi/drm/i915_drm.h | 27 +++++
> 10 files changed, 194 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/Kconfig.debug b/drivers/gpu/drm/i915/Kconfig.debug
> index 5b7162076850..32e9f70e91ed 100644
> --- a/drivers/gpu/drm/i915/Kconfig.debug
> +++ b/drivers/gpu/drm/i915/Kconfig.debug
> @@ -16,6 +16,23 @@ config DRM_I915_WERROR
>
> If in doubt, say "N".
>
> +config DRM_I915_REPLAY_GPU_HANGS_API
> + bool "Enable GPU hang replay userspace API"
> + depends on DRM_I915
> + depends on EXPERT
> + default n
> + help
> + Choose this option if you want to enable special and unstable
> + userspace API used for replaying GPU hangs on a running system.
> +
> + This API is intended to be used by userspace graphics stack developers
> + and provides no stability guarantees.
> +
> + The API needs to be activated at boot time using the
> + enable_debug_only_api module parameter.
> +
> + If in doubt, say "N".
> +
> config DRM_I915_DEBUG
> bool "Enable additional driver debugging"
> depends on DRM_I915
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> index dcbfe32fd30c..1cfd624bd978 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> @@ -78,6 +78,7 @@
> #include "gt/intel_engine_user.h"
> #include "gt/intel_gpu_commands.h"
> #include "gt/intel_ring.h"
> +#include "gt/shmem_utils.h"
>
> #include "pxp/intel_pxp.h"
>
> @@ -949,6 +950,7 @@ static int set_proto_ctx_param(struct drm_i915_file_private *fpriv,
> case I915_CONTEXT_PARAM_NO_ZEROMAP:
> case I915_CONTEXT_PARAM_BAN_PERIOD:
> case I915_CONTEXT_PARAM_RINGSIZE:
> + case I915_CONTEXT_PARAM_CONTEXT_IMAGE:
> default:
> ret = -EINVAL;
> break;
> @@ -2092,6 +2094,88 @@ static int get_protected(struct i915_gem_context *ctx,
> return 0;
> }
>
> +static int set_context_image(struct i915_gem_context *ctx,
> + struct drm_i915_gem_context_param *args)
> +{
> + struct i915_gem_context_param_context_image user;
> + struct intel_context *ce;
> + struct file *shmem_state;
> + unsigned long lookup;
> + void *state;
> + int ret = 0;
> +
> + if (!IS_ENABLED(CONFIG_DRM_I915_REPLAY_GPU_HANGS_API))
> + return -EINVAL;
> +
> + if (!ctx->i915->params.enable_debug_only_api)
> + return -EINVAL;
> +
> + if (args->size < sizeof(user))
> + return -EINVAL;
> +
> + if (copy_from_user(&user, u64_to_user_ptr(args->value), sizeof(user)))
> + return -EFAULT;
> +
> + if (user.mbz)
> + return -EINVAL;
> +
> + if (user.flags & ~(I915_CONTEXT_IMAGE_FLAG_ENGINE_INDEX))
> + return -EINVAL;
> +
> + lookup = 0;
> + if (user.flags & I915_CONTEXT_IMAGE_FLAG_ENGINE_INDEX)
> + lookup |= LOOKUP_USER_INDEX;
> +
> + ce = lookup_user_engine(ctx, lookup, &user.engine);
> + if (IS_ERR(ce))
> + return PTR_ERR(ce);
> +
> + if (user.size < ce->engine->context_size) {
> + ret = -EINVAL;
> + goto out_ce;
> + }
> +
> + if (test_bit(CONTEXT_ALLOC_BIT, &ce->flags)) {
> + ret = -EBUSY;
> + goto out_ce;
> + }
> +
> + state = kmalloc(ce->engine->context_size, GFP_KERNEL);
> + if (!state) {
> + ret = -ENOMEM;
> + goto out_ce;
> + }
> +
> + if (copy_from_user(state, u64_to_user_ptr(user.image),
> + ce->engine->context_size)) {
> + ret = -EFAULT;
> + goto out_state;
> + }
> +
> + shmem_state = shmem_create_from_data(ce->engine->name,
> + state, ce->engine->context_size);
> + if (IS_ERR(shmem_state)) {
> + ret = PTR_ERR(shmem_state);
> + goto out_state;
> + }
> +
> + if (intel_context_set_own_state(ce)) {
> + ret = -EBUSY;
> + fput(shmem_state);
> + goto out_state;
> + }
> +
> + ce->default_state = shmem_state;
> +
> + args->size = sizeof(user);
> +
> +out_state:
> + kfree(state);
> +out_ce:
> + intel_context_put(ce);
> + return ret;
> +}
> +
> static int ctx_setparam(struct drm_i915_file_private *fpriv,
> struct i915_gem_context *ctx,
> struct drm_i915_gem_context_param *args)
> @@ -2144,6 +2228,10 @@ static int ctx_setparam(struct drm_i915_file_private *fpriv,
> ret = set_persistence(ctx, args);
> break;
>
> + case I915_CONTEXT_PARAM_CONTEXT_IMAGE:
> + ret = set_context_image(ctx, args);
> + break;
> +
> case I915_CONTEXT_PARAM_PROTECTED_CONTENT:
> case I915_CONTEXT_PARAM_NO_ZEROMAP:
> case I915_CONTEXT_PARAM_BAN_PERIOD:
> @@ -2488,6 +2576,7 @@ int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data,
> case I915_CONTEXT_PARAM_BAN_PERIOD:
> case I915_CONTEXT_PARAM_ENGINES:
> case I915_CONTEXT_PARAM_RINGSIZE:
> + case I915_CONTEXT_PARAM_CONTEXT_IMAGE:
> default:
> ret = -EINVAL;
> break;
> @@ -2600,5 +2689,22 @@ int __init i915_gem_context_module_init(void)
> if (!slab_luts)
> return -ENOMEM;
>
> + if (IS_ENABLED(CONFIG_DRM_I915_REPLAY_GPU_HANGS_API)) {
> + pr_notice("**************************************************************\n");
> + pr_notice("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
> + pr_notice("** **\n");
> + if (i915_modparams.enable_debug_only_api)
> + pr_notice("** i915.enable_debug_only_api is intended to be set **\n");
> + else
> + pr_notice("** CONFIG_DRM_I915_REPLAY_GPU_HANGS_API builds are intended **\n");
> + pr_notice("** for specific userspace graphics stack developers only! **\n");
> + pr_notice("** **\n");
> + pr_notice("** If you are seeing this message please report this to the **\n");
> + pr_notice("** provider of your kernel build. **\n");
> + pr_notice("** **\n");
> + pr_notice("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
> + pr_notice("**************************************************************\n");
> + }
> +
> return 0;
> }
> diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c
> index a2f1245741bb..b1b8695ba7c9 100644
> --- a/drivers/gpu/drm/i915/gt/intel_context.c
> +++ b/drivers/gpu/drm/i915/gt/intel_context.c
> @@ -27,6 +27,8 @@ static void rcu_context_free(struct rcu_head *rcu)
> struct intel_context *ce = container_of(rcu, typeof(*ce), rcu);
>
> trace_intel_context_free(ce);
> + if (intel_context_has_own_state(ce))
> + fput(ce->default_state);
> kmem_cache_free(slab_ce, ce);
> }
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_context.h b/drivers/gpu/drm/i915/gt/intel_context.h
> index 25564c01507e..9f523999acd1 100644
> --- a/drivers/gpu/drm/i915/gt/intel_context.h
> +++ b/drivers/gpu/drm/i915/gt/intel_context.h
> @@ -375,6 +375,28 @@ intel_context_clear_nopreempt(struct intel_context *ce)
> clear_bit(CONTEXT_NOPREEMPT, &ce->flags);
> }
>
> +#if IS_ENABLED(CONFIG_DRM_I915_REPLAY_GPU_HANGS_API)
> +static inline bool intel_context_has_own_state(const struct intel_context *ce)
> +{
> + return test_bit(CONTEXT_OWN_STATE, &ce->flags);
> +}
> +
> +static inline bool intel_context_set_own_state(struct intel_context *ce)
> +{
> + return test_and_set_bit(CONTEXT_OWN_STATE, &ce->flags);
> +}
> +#else
> +static inline bool intel_context_has_own_state(const struct intel_context *ce)
> +{
> + return false;
> +}
> +
> +static inline bool intel_context_set_own_state(struct intel_context *ce)
> +{
> + return true;
> +}
> +#endif
> +
> u64 intel_context_get_total_runtime_ns(struct intel_context *ce);
> u64 intel_context_get_avg_runtime_ns(struct intel_context *ce);
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h
> index 7eccbd70d89f..b2ea14155ff0 100644
> --- a/drivers/gpu/drm/i915/gt/intel_context_types.h
> +++ b/drivers/gpu/drm/i915/gt/intel_context_types.h
> @@ -87,6 +87,8 @@ struct intel_context {
> struct rcu_head rcu;
> };
>
> + struct file *default_state;
> +
> struct intel_engine_cs *engine;
> struct intel_engine_cs *inflight;
> #define __intel_context_inflight(engine) ptr_mask_bits(engine, 3)
> @@ -130,6 +132,7 @@ struct intel_context {
> #define CONTEXT_PERMA_PIN 11
> #define CONTEXT_IS_PARKING 12
> #define CONTEXT_EXITING 13
> +#define CONTEXT_OWN_STATE 14
>
> struct {
> u64 timeout_us;
> diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
> index 7c367ba8d9dc..1038659754f8 100644
> --- a/drivers/gpu/drm/i915/gt/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
> @@ -1060,9 +1060,8 @@ void lrc_init_state(struct intel_context *ce,
>
> set_redzone(state, engine);
>
> - if (engine->default_state) {
> - shmem_read(engine->default_state, 0,
> - state, engine->context_size);
> + if (ce->default_state) {
> + shmem_read(ce->default_state, 0, state, engine->context_size);
> __set_bit(CONTEXT_VALID_BIT, &ce->flags);
> inhibit = false;
> }
> @@ -1174,6 +1173,9 @@ int lrc_alloc(struct intel_context *ce, struct intel_engine_cs *engine)
>
> GEM_BUG_ON(ce->state);
>
> + if (!intel_context_has_own_state(ce))
> + ce->default_state = engine->default_state;
> +
> vma = __lrc_alloc_state(ce, engine);
> if (IS_ERR(vma))
> return PTR_ERR(vma);
> diff --git a/drivers/gpu/drm/i915/gt/intel_ring_submission.c b/drivers/gpu/drm/i915/gt/intel_ring_submission.c
> index 92085ffd23de..72277bc8322e 100644
> --- a/drivers/gpu/drm/i915/gt/intel_ring_submission.c
> +++ b/drivers/gpu/drm/i915/gt/intel_ring_submission.c
> @@ -474,8 +474,7 @@ static int ring_context_init_default_state(struct intel_context *ce,
> if (IS_ERR(vaddr))
> return PTR_ERR(vaddr);
>
> - shmem_read(ce->engine->default_state, 0,
> - vaddr, ce->engine->context_size);
> + shmem_read(ce->default_state, 0, vaddr, ce->engine->context_size);
>
> i915_gem_object_flush_map(obj);
> __i915_gem_object_release_map(obj);
> @@ -491,7 +490,7 @@ static int ring_context_pre_pin(struct intel_context *ce,
> struct i915_address_space *vm;
> int err = 0;
>
> - if (ce->engine->default_state &&
> + if (ce->default_state &&
> !test_bit(CONTEXT_VALID_BIT, &ce->flags)) {
> err = ring_context_init_default_state(ce, ww);
> if (err)
> @@ -570,6 +569,9 @@ static int ring_context_alloc(struct intel_context *ce)
> {
> struct intel_engine_cs *engine = ce->engine;
>
> + if (!intel_context_has_own_state(ce))
> + ce->default_state = engine->default_state;
> +
> /* One ringbuffer to rule them all */
> GEM_BUG_ON(!engine->legacy.ring);
> ce->ring = engine->legacy.ring;
> diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
> index de43048543e8..1226af5fd96f 100644
> --- a/drivers/gpu/drm/i915/i915_params.c
> +++ b/drivers/gpu/drm/i915/i915_params.c
> @@ -134,6 +134,11 @@ i915_param_named_unsafe(lmem_size, uint, 0400,
> i915_param_named_unsafe(lmem_bar_size, uint, 0400,
> "Set the lmem bar size(in MiB).");
>
> +#if IS_ENABLED(CONFIG_DRM_I915_REPLAY_GPU_HANGS_API)
> +i915_param_named(enable_debug_only_api, bool, 0400,
> + "Enable support for unstable debug only userspace API. (default:false)");
> +#endif
> +
> static void _param_print_bool(struct drm_printer *p, const char *name,
> bool val)
> {
> diff --git a/drivers/gpu/drm/i915/i915_params.h b/drivers/gpu/drm/i915/i915_params.h
> index 1315d7fac850..e2cdf12ce611 100644
> --- a/drivers/gpu/drm/i915/i915_params.h
> +++ b/drivers/gpu/drm/i915/i915_params.h
> @@ -64,7 +64,8 @@ struct drm_printer;
> /* leave bools at the end to not create holes */ \
> param(bool, enable_hangcheck, true, 0600) \
> param(bool, error_capture, true, IS_ENABLED(CONFIG_DRM_I915_CAPTURE_ERROR) ? 0600 : 0) \
> - param(bool, enable_gvt, false, IS_ENABLED(CONFIG_DRM_I915_GVT) ? 0400 : 0)
> + param(bool, enable_gvt, false, IS_ENABLED(CONFIG_DRM_I915_GVT) ? 0400 : 0) \
> + param(bool, enable_debug_only_api, false, IS_ENABLED(CONFIG_DRM_I915_REPLAY_GPU_HANGS_API) ? 0400 : 0)
>
> #define MEMBER(T, member, ...) T member;
> struct i915_params {
> diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> index fd4f9574d177..0af932e61d12 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> @@ -2154,6 +2154,15 @@ struct drm_i915_gem_context_param {
> __u64 value;
> };
>
> +/*
> + * I915_CONTEXT_PARAM_CONTEXT_IMAGE:
> + *
> + * Allows userspace to provide own context images.
> + *
> + * Note that this is a debug API not available on production kernel builds.
> + */
> +#define I915_CONTEXT_PARAM_CONTEXT_IMAGE 0xe
> +
> /*
> * Context SSEU programming
> *
> @@ -2549,6 +2558,24 @@ struct i915_context_param_engines {
> struct i915_engine_class_instance engines[N__]; \
> } __attribute__((packed)) name__
>
> +struct i915_gem_context_param_context_image {
> + /** @engine: Engine class & instance to be configured. */
> + struct i915_engine_class_instance engine;
> +
> + /** @flags: One of the supported flags or zero. */
> + __u32 flags;
> +#define I915_CONTEXT_IMAGE_FLAG_ENGINE_INDEX (1u << 0)
> +
> + /** @size: Size of the image blob pointed to by @image. */
> + __u32 size;
> +
> + /** @mbz: Must be zero. */
> + __u32 mbz;
> +
> + /** @image: Userspace memory containing the context image. */
> + __u64 image;
> +} __attribute__((packed));
> +
> /**
> * struct drm_i915_gem_context_create_ext_setparam - Context parameter
> * to set or query during context creation.
> --
> 2.40.1
>
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