[PATCH v4 14/17] drm/i915/pxp: User interface for Protected buffer
Daniel Vetter
daniel at ffwll.ch
Tue May 25 13:32:38 UTC 2021
On Mon, May 24, 2021 at 10:48:00PM -0700, Daniele Ceraolo Spurio wrote:
> From: Bommu Krishnaiah <krishnaiah.bommu at intel.com>
>
> This api allow user mode to create Protected buffers. Only contexts
> marked as protected are allowed to operate on protected buffers.
>
> We only allow setting the flags at creation time.
>
> All protected objects that have backing storage will be considered
> invalid when the session is destroyed and they won't be usable anymore.
>
> Given that the PXP HW supports multiple modes (but we currently only
> care about one), a flag variable has been reserved in the structure
> used in the create_ext ioctl for possible future updates.
>
> This is a rework of the original code by Bommu Krishnaiah. I've kept
> authorship unchanged since significant chunks have not been modified.
>
> v2: split context changes, fix defines and improve documentation (Chris),
> add object invalidation logic
> v3: fix spinlock definition and usage, only validate objects when
> they're first added to a context lut, only remove them once (Chris),
> make protected context flag not mandatory in protected object execbuf
> to avoid abuse (Lionel)
> v4: rebase to new gem_create_ext
>
> Signed-off-by: Bommu Krishnaiah <krishnaiah.bommu at intel.com>
> Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> Cc: Telukuntla Sreedhar <sreedhar.telukuntla at intel.com>
> Cc: Kondapally Kalyan <kalyan.kondapally at intel.com>
> Cc: Gupta Anshuman <Anshuman.Gupta at intel.com>
> Cc: Huang Sean Z <sean.z.huang at intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
> Cc: Jason Ekstrand <jason at jlekstrand.net>
> Cc: Daniel Vetter <daniel.vetter at intel.com>
> ---
> drivers/gpu/drm/i915/gem/i915_gem_create.c | 26 ++++++++++++
> .../gpu/drm/i915/gem/i915_gem_execbuffer.c | 15 +++++++
> drivers/gpu/drm/i915/gem/i915_gem_object.c | 6 +++
> drivers/gpu/drm/i915/gem/i915_gem_object.h | 12 ++++++
> .../gpu/drm/i915/gem/i915_gem_object_types.h | 13 ++++++
> drivers/gpu/drm/i915/pxp/intel_pxp.c | 41 +++++++++++++++++++
> drivers/gpu/drm/i915/pxp/intel_pxp.h | 13 ++++++
> drivers/gpu/drm/i915/pxp/intel_pxp_types.h | 5 +++
> include/uapi/drm/i915_drm.h | 33 ++++++++++++++-
> 9 files changed, 163 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_create.c b/drivers/gpu/drm/i915/gem/i915_gem_create.c
> index 548ddf39d853..c14be3882c35 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_create.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_create.c
> @@ -6,6 +6,7 @@
> #include "gem/i915_gem_ioctls.h"
> #include "gem/i915_gem_lmem.h"
> #include "gem/i915_gem_region.h"
> +#include "pxp/intel_pxp.h"
>
> #include "i915_drv.h"
> #include "i915_trace.h"
> @@ -99,7 +100,11 @@ i915_gem_setup(struct drm_i915_gem_object *obj, u64 size)
>
> GEM_BUG_ON(size != obj->base.size);
>
> + if (obj->user_flags & I915_GEM_OBJECT_PROTECTED)
> + intel_pxp_object_add(obj);
> +
> trace_i915_gem_object_create(obj);
> +
> return 0;
> }
>
> @@ -344,8 +349,29 @@ static int ext_set_placements(struct i915_user_extension __user *base,
> return set_placements(&ext, data);
> }
>
> +static int ext_set_protected(struct i915_user_extension __user *base, void *data)
> +{
> + struct drm_i915_gem_create_ext_protected_content ext;
> + struct create_ext *ext_data = data;
> +
> + if (copy_from_user(&ext, base, sizeof(ext)))
> + return -EFAULT;
> +
> + if (ext.flags)
> + return -EINVAL;
> +
> + if (!intel_pxp_is_enabled(&ext_data->i915->gt.pxp))
> + return -ENODEV;
> +
> + ext_data->vanilla_object->user_flags |= I915_GEM_OBJECT_PROTECTED;
> +
> + return 0;
> +}
> +
> +
> static const i915_user_extension_fn create_extensions[] = {
> [I915_GEM_CREATE_EXT_MEMORY_REGIONS] = ext_set_placements,
> + [I915_GEM_CREATE_EXT_PROTECTED_CONTENT] = ext_set_protected,
> };
>
> /**
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> index c08e28847064..5dd813d04a9f 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> @@ -839,6 +839,21 @@ static struct i915_vma *eb_lookup_vma(struct i915_execbuffer *eb, u32 handle)
> if (unlikely(!obj))
> return ERR_PTR(-ENOENT);
>
> + /*
> + * If the user has opted-in for protected-object tracking, make
> + * sure the object encryption can be used.
> + * We only need to do this when the object is first used with
> + * this context, because the context itself will be banned when
> + * the protected objects become invalid.
> + */
> + if (i915_gem_context_uses_protected_content(eb->gem_context) &&
> + i915_gem_object_is_protected(obj)) {
> + if (!intel_pxp_is_active(&vm->gt->pxp))
> + return ERR_PTR(-ENODEV);
> + if (!i915_gem_object_has_valid_protection(obj))
> + return ERR_PTR(-ENOEXEC);
> + }
> +
> vma = i915_vma_instance(obj, vm, NULL);
> if (IS_ERR(vma)) {
> i915_gem_object_put(obj);
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.c b/drivers/gpu/drm/i915/gem/i915_gem_object.c
> index 28144410df86..b47fa0a7b25a 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_object.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.c
> @@ -25,6 +25,7 @@
> #include <linux/sched/mm.h>
>
> #include "display/intel_frontbuffer.h"
> +#include "pxp/intel_pxp.h"
> #include "i915_drv.h"
> #include "i915_gem_clflush.h"
> #include "i915_gem_context.h"
> @@ -70,6 +71,8 @@ void i915_gem_object_init(struct drm_i915_gem_object *obj,
> INIT_LIST_HEAD(&obj->lut_list);
> spin_lock_init(&obj->lut_lock);
>
> + INIT_LIST_HEAD(&obj->pxp_link);
> +
> spin_lock_init(&obj->mmo.lock);
> obj->mmo.offsets = RB_ROOT;
>
> @@ -232,6 +235,9 @@ static void __i915_gem_free_objects(struct drm_i915_private *i915,
> spin_unlock(&obj->vma.lock);
> }
>
> + if (i915_gem_object_has_valid_protection(obj))
> + intel_pxp_object_remove(obj);
> +
> __i915_gem_object_free_mmaps(obj);
>
> GEM_BUG_ON(!list_empty(&obj->lut_list));
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> index 2ebd79537aea..61b101560352 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> @@ -288,6 +288,18 @@ i915_gem_object_never_mmap(const struct drm_i915_gem_object *obj)
> return i915_gem_object_type_has(obj, I915_GEM_OBJECT_NO_MMAP);
> }
>
> +static inline bool
> +i915_gem_object_is_protected(const struct drm_i915_gem_object *obj)
> +{
> + return obj->user_flags & I915_GEM_OBJECT_PROTECTED;
> +}
> +
> +static inline bool
> +i915_gem_object_has_valid_protection(const struct drm_i915_gem_object *obj)
> +{
> + return i915_gem_object_is_protected(obj) && !list_empty(&obj->pxp_link);
> +}
> +
> static inline bool
> i915_gem_object_is_framebuffer(const struct drm_i915_gem_object *obj)
> {
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
> index 0727d0c76aa0..a698ad0ef7f6 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
> @@ -167,6 +167,11 @@ struct drm_i915_gem_object {
> } mmo;
>
> I915_SELFTEST_DECLARE(struct list_head st_link);
> + /**
> + * @user_flags: small set of booleans set by the user
> + */
> + unsigned long user_flags;
> +#define I915_GEM_OBJECT_PROTECTED BIT(0)
>
> unsigned long flags;
> #define I915_BO_ALLOC_CONTIGUOUS BIT(0)
> @@ -294,6 +299,14 @@ struct drm_i915_gem_object {
> bool dirty:1;
> } mm;
>
> + /*
> + * When the PXP session is invalidated, we need to mark all protected
> + * objects as invalid. To easily do so we add them all to a list. The
> + * presence on the list is used to check if the encryption is valid or
> + * not.
> + */
> + struct list_head pxp_link;
> +
> /** Record of address bit 17 of each page at last unbind. */
> unsigned long *bit_17;
>
> diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp.c b/drivers/gpu/drm/i915/pxp/intel_pxp.c
> index 2291c68fd3a0..e6a59eb05eae 100644
> --- a/drivers/gpu/drm/i915/pxp/intel_pxp.c
> +++ b/drivers/gpu/drm/i915/pxp/intel_pxp.c
> @@ -69,6 +69,9 @@ void intel_pxp_init(struct intel_pxp *pxp)
> if (!HAS_PXP(gt->i915))
> return;
>
> + spin_lock_init(&pxp->lock);
> + INIT_LIST_HEAD(&pxp->protected_objects);
> +
> /*
> * we'll use the completion to check if there is a termination pending,
> * so we start it as completed and we reinit it when a termination
> @@ -177,11 +180,49 @@ void intel_pxp_fini_hw(struct intel_pxp *pxp)
> intel_pxp_irq_disable(pxp);
> }
>
> +int intel_pxp_object_add(struct drm_i915_gem_object *obj)
> +{
> + struct intel_pxp *pxp = &to_i915(obj->base.dev)->gt.pxp;
> +
> + if (!intel_pxp_is_enabled(pxp))
> + return -ENODEV;
> +
> + if (!list_empty(&obj->pxp_link))
> + return -EEXIST;
> +
> + spin_lock_irq(&pxp->lock);
> + list_add(&obj->pxp_link, &pxp->protected_objects);
> + spin_unlock_irq(&pxp->lock);
> +
> + return 0;
> +}
> +
> +void intel_pxp_object_remove(struct drm_i915_gem_object *obj)
> +{
> + struct intel_pxp *pxp = &to_i915(obj->base.dev)->gt.pxp;
> +
> + if (!intel_pxp_is_enabled(pxp))
> + return;
> +
> + spin_lock_irq(&pxp->lock);
> + list_del_init(&obj->pxp_link);
> + spin_unlock_irq(&pxp->lock);
> +}
> +
> void intel_pxp_invalidate(struct intel_pxp *pxp)
> {
> struct drm_i915_private *i915 = pxp_to_gt(pxp)->i915;
> + struct drm_i915_gem_object *obj, *tmp;
> struct i915_gem_context *ctx, *cn;
>
> + /* delete objects that have been used with the invalidated session */
> + spin_lock_irq(&pxp->lock);
> + list_for_each_entry_safe(obj, tmp, &pxp->protected_objects, pxp_link) {
> + if (i915_gem_object_has_pages(obj))
> + list_del_init(&obj->pxp_link);
> + }
> + spin_unlock_irq(&pxp->lock);
> +
> /* ban all contexts marked as protected */
> spin_lock_irq(&i915->gem.contexts.lock);
> list_for_each_entry_safe(ctx, cn, &i915->gem.contexts.list, link) {
> diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp.h b/drivers/gpu/drm/i915/pxp/intel_pxp.h
> index 1f9871e64096..3500d7896058 100644
> --- a/drivers/gpu/drm/i915/pxp/intel_pxp.h
> +++ b/drivers/gpu/drm/i915/pxp/intel_pxp.h
> @@ -9,6 +9,8 @@
> #include "gt/intel_gt_types.h"
> #include "intel_pxp_types.h"
>
> +struct drm_i915_gem_object;
> +
> static inline struct intel_gt *pxp_to_gt(const struct intel_pxp *pxp)
> {
> return container_of(pxp, struct intel_gt, pxp);
> @@ -33,6 +35,9 @@ void intel_pxp_fini_hw(struct intel_pxp *pxp);
>
> void intel_pxp_mark_termination_in_progress(struct intel_pxp *pxp);
> int intel_pxp_start(struct intel_pxp *pxp);
> +
> +int intel_pxp_object_add(struct drm_i915_gem_object *obj);
> +void intel_pxp_object_remove(struct drm_i915_gem_object *obj);
> void intel_pxp_invalidate(struct intel_pxp *pxp);
> #else
> static inline void intel_pxp_init(struct intel_pxp *pxp)
> @@ -47,6 +52,14 @@ static inline int intel_pxp_start(struct intel_pxp *pxp)
> {
> return 0;
> }
> +
> +static inline int intel_pxp_object_add(struct drm_i915_gem_object *obj)
> +{
> + return 0;
> +}
> +static inline void intel_pxp_object_remove(struct drm_i915_gem_object *obj)
> +{
> +}
> #endif
>
> #endif /* __INTEL_PXP_H__ */
> diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_types.h b/drivers/gpu/drm/i915/pxp/intel_pxp_types.h
> index b3ae49dd73a8..cc510416eac6 100644
> --- a/drivers/gpu/drm/i915/pxp/intel_pxp_types.h
> +++ b/drivers/gpu/drm/i915/pxp/intel_pxp_types.h
> @@ -7,7 +7,9 @@
> #define __INTEL_PXP_TYPES_H__
>
> #include <linux/completion.h>
> +#include <linux/list.h>
> #include <linux/mutex.h>
> +#include <linux/spinlock.h>
> #include <linux/types.h>
> #include <linux/workqueue.h>
>
> @@ -43,6 +45,9 @@ struct intel_pxp {
> #define PXP_TERMINATION_REQUEST BIT(0)
> #define PXP_TERMINATION_COMPLETE BIT(1)
> #define PXP_INVAL_REQUIRED BIT(2)
> +
> + spinlock_t lock; /* protects the objects list */
> + struct list_head protected_objects;
> };
>
> #endif /* __INTEL_PXP_TYPES_H__ */
> diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> index 3cc33fcbf520..d39b8cb4bfc5 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
For easier review it would be nice to have all the uapi and its kerneldoc
in one patch. I feel like I've missed parts.
> @@ -1768,7 +1768,7 @@ struct drm_i915_gem_context_param {
> __u64 value;
> };
>
> -/*
> +/**
> * Context SSEU programming
> *
> * It may be necessary for either functional or performance reason to configure
> @@ -2669,8 +2669,12 @@ struct drm_i915_gem_create_ext {
> *
> * For I915_GEM_CREATE_EXT_MEMORY_REGIONS usage see
> * struct drm_i915_gem_create_ext_memory_regions.
> + *
> + * For I915_GEM_CREATE_EXT_PROTECTED_CONTENT usage see
> + * struct drm_i915_gem_create_ext_protected_content.
> */
> #define I915_GEM_CREATE_EXT_MEMORY_REGIONS 0
> +#define I915_GEM_CREATE_EXT_PROTECTED_CONTENT 1
> __u64 extensions;
> };
>
> @@ -2728,6 +2732,33 @@ struct drm_i915_gem_create_ext_memory_regions {
> __u64 regions;
> };
>
> +/**
> + * struct drm_i915_gem_create_ext_protected_content - The
> + * I915_OBJECT_PARAM_PROTECTED_CONTENT extension.
> + *
> + * If this extension is provided, buffer contents are expected to be
> + * protected by PXP encryption and requires decryption for scan out
> + * and processing. This is only possible on platforms that have PXP enabled,
> + * on all other scenarios ysing this extension will cause the ioctl to fail
> + * and return -ENODEV. The flags parameter is reserved for future expansion and
> + * must currently be set to zero.
> + *
> + * The buffer contents are considered invalid after a PXP session teardown.
> + *
> + * The encryption is guaranteed to be processed correctly only if the object
> + * is submitted with a context created using the
> + * I915_CONTEXT_PARAM_PROTECTED_CONTENT flag. This will also enable extra checks
Not finding the kerneldoc for this. Also is this a CTX_CREATE_EXT flag, so
guaranteed to be immutable, or is this another CTX_SETPARAM flag, which
would be mutable and we really want to get away from that paradigm?
> + * at submission time on the validity of the objects involved, which can lead to
> + * the following errors being returned from the execbuf ioctl:
I think this also should be put into the execbuf ioctl structs. Plus I
think RESET_STATS should also explain how this interacts and all that.
Here we should just reference this other sections imo.
Yes this means a bit more to type because not even the bare bones of these
other ioctl kerneldocs exists, but we have to start somewhere.
Cheers, Daniel
> + *
> + * -ENODEV: PXP session not currently active
> + * -ENOEXEC: buffer has become invalid after a teardown event
> + */
> +struct drm_i915_gem_create_ext_protected_content {
> + struct i915_user_extension base;
> + __u32 flags;
> +};
> +
> /* ID of the protected content session managed by i915 when PXP is active */
> #define I915_PROTECTED_CONTENT_DEFAULT_SESSION 0xf
>
> --
> 2.29.2
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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