[Intel-gfx] [PATCH v3 13/16] drm/i915/pxp: User interface for Protected buffer
Lionel Landwerlin
lionel.g.landwerlin at intel.com
Thu Apr 1 12:05:19 UTC 2021
On 29/03/2021 01:57, 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.
>
> This is a rework of the original code by Bommu Krishnaiah. I've
> 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)
>
> 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>
> ---
> drivers/gpu/drm/i915/gem/i915_gem_create.c | 27 ++++++++++--
> .../gpu/drm/i915/gem/i915_gem_execbuffer.c | 16 ++++++++
> 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 | 20 +++++++++
> 9 files changed, 150 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_create.c b/drivers/gpu/drm/i915/gem/i915_gem_create.c
> index 3ad3413c459f..d02e5938afbe 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_create.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_create.c
> @@ -5,6 +5,7 @@
>
> #include "gem/i915_gem_ioctls.h"
> #include "gem/i915_gem_region.h"
> +#include "pxp/intel_pxp.h"
>
> #include "i915_drv.h"
> #include "i915_user_extensions.h"
> @@ -13,7 +14,8 @@ static int
> i915_gem_create(struct drm_file *file,
> struct intel_memory_region *mr,
> u64 *size_p,
> - u32 *handle_p)
> + u32 *handle_p,
> + u64 user_flags)
> {
> struct drm_i915_gem_object *obj;
> u32 handle;
> @@ -35,12 +37,17 @@ i915_gem_create(struct drm_file *file,
>
> GEM_BUG_ON(size != obj->base.size);
>
> + obj->user_flags = user_flags;
> +
> ret = drm_gem_handle_create(file, &obj->base, &handle);
> /* drop reference from allocate - handle holds it now */
> i915_gem_object_put(obj);
> if (ret)
> return ret;
>
> + if (user_flags & I915_GEM_OBJECT_PROTECTED)
> + intel_pxp_object_add(obj);
> +
> *handle_p = handle;
> *size_p = size;
> return 0;
> @@ -89,11 +96,12 @@ i915_gem_dumb_create(struct drm_file *file,
> return i915_gem_create(file,
> intel_memory_region_by_type(to_i915(dev),
> mem_type),
> - &args->size, &args->handle);
> + &args->size, &args->handle, 0);
> }
>
> struct create_ext {
> struct drm_i915_private *i915;
> + unsigned long user_flags;
> };
>
> static int __create_setparam(struct drm_i915_gem_object_param *args,
> @@ -104,6 +112,19 @@ static int __create_setparam(struct drm_i915_gem_object_param *args,
> return -EINVAL;
> }
>
> + switch (lower_32_bits(args->param)) {
> + case I915_OBJECT_PARAM_PROTECTED_CONTENT:
> + if (!intel_pxp_is_enabled(&ext_data->i915->gt.pxp))
> + return -ENODEV;
> + if (args->size) {
> + return -EINVAL;
> + } else if (args->data) {
> + ext_data->user_flags |= I915_GEM_OBJECT_PROTECTED;
> + return 0;
> + }
> + break;
> + }
> +
> return -EINVAL;
> }
>
> @@ -148,5 +169,5 @@ i915_gem_create_ioctl(struct drm_device *dev, void *data,
> return i915_gem_create(file,
> intel_memory_region_by_type(i915,
> INTEL_MEMORY_SYSTEM),
> - &args->size, &args->handle);
> + &args->size, &args->handle, ext_data.user_flags);
> }
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> index 72c2470fcfe6..2fb6579ad301 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> @@ -20,6 +20,7 @@
> #include "gt/intel_gt_buffer_pool.h"
> #include "gt/intel_gt_pm.h"
> #include "gt/intel_ring.h"
> +#include "pxp/intel_pxp.h"
>
> #include "pxp/intel_pxp.h"
>
> @@ -839,6 +840,21 @@ 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(-EIO);
> + }
> +
> 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 ea74cbca95be..80ccefd641e8 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 8e485cb3343c..0d4bd2747375 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)
> @@ -286,6 +291,14 @@ 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 cbc5249a1bf9..7f9902eac7ec 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
> @@ -173,11 +176,49 @@ 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 91c1a2056309..194b00149247 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_wait_for_arb_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_wait_for_arb_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 6c9265fb8e4b..665704d7793e 100644
> --- a/drivers/gpu/drm/i915/pxp/intel_pxp_types.h
> +++ b/drivers/gpu/drm/i915/pxp/intel_pxp_types.h
> @@ -7,8 +7,10 @@
> #define __INTEL_PXP_TYPES_H__
>
> #include <linux/completion.h>
> +#include <linux/list.h>
> #include <linux/types.h>
> #include <linux/mutex.h>
> +#include <linux/spinlock.h>
> #include <linux/workqueue.h>
>
> struct intel_context;
> @@ -33,6 +35,9 @@ struct intel_pxp {
> u32 session_events; /* protected with gt->irq_lock */
> #define PXP_TERMINATION_REQUEST BIT(0)
> #define PXP_TERMINATION_COMPLETE BIT(1)
> +
> + 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 d5e502269a55..420412c08745 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> @@ -1756,6 +1756,26 @@ struct drm_i915_gem_object_param {
> */
> #define I915_OBJECT_PARAM (1ull << 32)
>
> +/*
> + * I915_OBJECT_PARAM_PROTECTED_CONTENT:
> + *
> + * If set to true, buffer contents is 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
> + * setting this flag will cause the ioctl to fail and return -ENODEV.
> + *
> + * The buffer contents are considered invalid after a PXP session teardown.
> + * It is recommended to use protected buffers only with contexts created
> + * using the I915_CONTEXT_PARAM_PROTECTED_CONTENT flag, as that will enable
> + * extra checks at submission time on the validity of the objects involved,
> + * which can lead to the following errors:
> + *
> + * -ENODEV: PXP session not currently active
> + * -EIO: buffer has become invalid after a teardown event
I was a bit confused on reading those comments. Maybe we should specify
when they apply.
My understanding is that you can get -ENODEV on object creation, while
-EIO happens at execbuffer time.
Did I get this right?
-Lionel
> + */
> +#define I915_OBJECT_PARAM_PROTECTED_CONTENT 0x0
> +/* Must be kept compact -- no holes and well documented */
> +
> __u64 param;
>
> /* Data value or pointer */
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