[Intel-gfx] [PATCH v11 09/17] drm/i915/pxp: Implement PXP irq handler

Alan Previn
2021-09-22T00:15:22Z

From: "Huang, Sean Z" <sean.z.huang@intel.com>

The HW will generate a teardown interrupt when session termination is
required, which requires i915 to submit a terminating batch. Once the HW
is done with the termination it will generate another interrupt, at
which point it is safe to re-create the session.

Since the termination and re-creation flow is something we want to
trigger from the driver as well, use a common work function that can be
called both from the irq handler and from the driver set-up flows, which
has the addded benefit of allowing us to skip any extra locks because
the work itself serializes the operations.

v2: use struct completion instead of bool (Chris)
v3: drop locks, clean up functions and improve comments (Chris),
move to common work function.
v4: improve comments, simplify wait logic (Rodrigo)
v5: unconditionally set interrupts, rename state_attacked var (Rodrigo)
v10: remove inclusion of intel_gt_types.h from intel_pxp.h (Jani)

Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Signed-off-by: Huang, Sean Z <sean.z.huang@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
---
drivers/gpu/drm/i915/Makefile | 1 +
drivers/gpu/drm/i915/gt/intel_gt_irq.c | 7 ++
drivers/gpu/drm/i915/i915_reg.h | 1 +
drivers/gpu/drm/i915/pxp/intel_pxp.c | 66 ++++++++++--
drivers/gpu/drm/i915/pxp/intel_pxp.h | 8 ++
drivers/gpu/drm/i915/pxp/intel_pxp_irq.c | 100 +++++++++++++++++++
drivers/gpu/drm/i915/pxp/intel_pxp_irq.h | 32 ++++++
drivers/gpu/drm/i915/pxp/intel_pxp_session.c | 54 +++++++++-
drivers/gpu/drm/i915/pxp/intel_pxp_session.h | 5 +-
drivers/gpu/drm/i915/pxp/intel_pxp_tee.c | 8 +-
drivers/gpu/drm/i915/pxp/intel_pxp_types.h | 18 ++++
11 files changed, 284 insertions(+), 16 deletions(-)
create mode 100644 drivers/gpu/drm/i915/pxp/intel_pxp_irq.c
create mode 100644 drivers/gpu/drm/i915/pxp/intel_pxp_irq.h

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index ac4585f98e43..32240dc032bd 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -284,6 +284,7 @@ i915-y += i915_perf.o
i915-$(CONFIG_DRM_I915_PXP) += \
pxp/intel_pxp.o \
pxp/intel_pxp_cmd.o \
+ pxp/intel_pxp_irq.o \
pxp/intel_pxp_session.o \
pxp/intel_pxp_tee.o

diff --git a/drivers/gpu/drm/i915/gt/intel_gt_irq.c b/drivers/gpu/drm/i915/gt/intel_gt_irq.c
index b2de83be4d97..699a74582d32 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_irq.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_irq.c
@@ -13,6 +13,7 @@
#include "intel_lrc_reg.h"
#include "intel_uncore.h"
#include "intel_rps.h"
+#include "pxp/intel_pxp_irq.h"

static void guc_irq_handler(struct intel_guc *guc, u16 iir)
{
@@ -64,6 +65,9 @@ gen11_other_irq_handler(struct intel_gt *gt, const u8 instance,
if (instance == OTHER_GTPM_INSTANCE)
return gen11_rps_irq_handler(&gt->rps, iir);

+ if (instance == OTHER_KCR_INSTANCE)
+ return intel_pxp_irq_handler(&gt->pxp, iir);
+
WARN_ONCE(1, "unhandled other interrupt instance=0x%x, iir=0x%x\n",
instance, iir);
}
@@ -196,6 +200,9 @@ void gen11_gt_irq_reset(struct intel_gt *gt)
intel_uncore_write(uncore, GEN11_GPM_WGBOXPERF_INTR_MASK, ~0);
intel_uncore_write(uncore, GEN11_GUC_SG_INTR_ENABLE, 0);
intel_uncore_write(uncore, GEN11_GUC_SG_INTR_MASK, ~0);
+
+ intel_uncore_write(uncore, GEN11_CRYPTO_RSVD_INTR_ENABLE, 0);
+ intel_uncore_write(uncore, GEN11_CRYPTO_RSVD_INTR_MASK, ~0);
}

void gen11_gt_irq_postinstall(struct intel_gt *gt)
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index cad84c3b864b..810f6f31b6cb 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -8117,6 +8117,7 @@ enum {
/* irq instances for OTHER_CLASS */
#define OTHER_GUC_INSTANCE 0
#define OTHER_GTPM_INSTANCE 1
+#define OTHER_KCR_INSTANCE 4

#define GEN11_INTR_IDENTITY_REG(x) _MMIO(0x190060 + ((x) * 4))

diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp.c b/drivers/gpu/drm/i915/pxp/intel_pxp.c
index a589d40e08a8..95593e84d40f 100644
--- a/drivers/gpu/drm/i915/pxp/intel_pxp.c
+++ b/drivers/gpu/drm/i915/pxp/intel_pxp.c
@@ -2,7 +2,9 @@
/*
* Copyright(c) 2020 Intel Corporation.
*/
+#include <linux/workqueue.h>
#include "intel_pxp.h"
+#include "intel_pxp_irq.h"
#include "intel_pxp_session.h"
#include "intel_pxp_tee.h"
#include "gt/intel_context.h"
@@ -79,6 +81,16 @@ void intel_pxp_init(struct intel_pxp *pxp)

mutex_init(&pxp->tee_mutex);

+ /*
+ * 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
+ * is triggered.
+ */
+ init_completion(&pxp->termination);
+ complete_all(&pxp->termination);
+
+ INIT_WORK(&pxp->session_work, intel_pxp_session_work);
+
ret = create_vcs_context(pxp);
if (ret)
return;
@@ -107,19 +119,61 @@ void intel_pxp_fini(struct intel_pxp *pxp)
destroy_vcs_context(pxp);
}

-void intel_pxp_init_hw(struct intel_pxp *pxp)
+void intel_pxp_mark_termination_in_progress(struct intel_pxp *pxp)
{
- int ret;
+ pxp->arb_is_valid = false;
+ reinit_completion(&pxp->termination);
+}
+
+static void intel_pxp_queue_termination(struct intel_pxp *pxp)
+{
+ struct intel_gt *gt = pxp_to_gt(pxp);
+
+ /*
+ * We want to get the same effect as if we received a termination
+ * interrupt, so just pretend that we did.
+ */
+ spin_lock_irq(&gt->irq_lock);
+ intel_pxp_mark_termination_in_progress(pxp);
+ pxp->session_events |= PXP_TERMINATION_REQUEST;
+ queue_work(system_unbound_wq, &pxp->session_work);
+ spin_unlock_irq(&gt->irq_lock);
+}

+/*
+ * the arb session is restarted from the irq work when we receive the
+ * termination completion interrupt
+ */
+int intel_pxp_wait_for_arb_start(struct intel_pxp *pxp)
+{
+ if (!intel_pxp_is_enabled(pxp))
+ return 0;
+
+ if (!wait_for_completion_timeout(&pxp->termination,
+ msecs_to_jiffies(100)))
+ return -ETIMEDOUT;
+
+ if (!pxp->arb_is_valid)
+ return -EIO;
+
+ return 0;
+}
+
+void intel_pxp_init_hw(struct intel_pxp *pxp)
+{
kcr_pxp_enable(pxp_to_gt(pxp));
+ intel_pxp_irq_enable(pxp);

- /* always emit a full termination to clean the state */
- ret = intel_pxp_terminate_arb_session_and_global(pxp);
- if (!ret)
- intel_pxp_create_arb_session(pxp);
+ /*
+ * the session could've been attacked while we weren't loaded, so
+ * handle it as if it was and re-create it.
+ */
+ intel_pxp_queue_termination(pxp);
}

void intel_pxp_fini_hw(struct intel_pxp *pxp)
{
kcr_pxp_disable(pxp_to_gt(pxp));
+
+ intel_pxp_irq_disable(pxp);
}
diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp.h b/drivers/gpu/drm/i915/pxp/intel_pxp.h
index 2960e8338c82..54b268280379 100644
--- a/drivers/gpu/drm/i915/pxp/intel_pxp.h
+++ b/drivers/gpu/drm/i915/pxp/intel_pxp.h
@@ -22,6 +22,9 @@ void intel_pxp_fini(struct intel_pxp *pxp);

void intel_pxp_init_hw(struct intel_pxp *pxp);
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);
#else
static inline void intel_pxp_init(struct intel_pxp *pxp)
{
@@ -30,6 +33,11 @@ static inline void intel_pxp_init(struct intel_pxp *pxp)
static inline void intel_pxp_fini(struct intel_pxp *pxp)
{
}
+
+static inline int intel_pxp_wait_for_arb_start(struct intel_pxp *pxp)
+{
+ return -ENODEV;
+}
#endif

#endif /* __INTEL_PXP_H__ */
diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_irq.c b/drivers/gpu/drm/i915/pxp/intel_pxp_irq.c
new file mode 100644
index 000000000000..300cf2b96fda
--- /dev/null
+++ b/drivers/gpu/drm/i915/pxp/intel_pxp_irq.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright(c) 2020 Intel Corporation.
+ */
+#include <linux/workqueue.h>
+#include "intel_pxp.h"
+#include "intel_pxp_irq.h"
+#include "intel_pxp_session.h"
+#include "gt/intel_gt_irq.h"
+#include "gt/intel_gt_types.h"
+#include "i915_irq.h"
+#include "i915_reg.h"
+
+/**
+ * intel_pxp_irq_handler - Handles PXP interrupts.
+ * @pxp: pointer to pxp struct
+ * @iir: interrupt vector
+ */
+void intel_pxp_irq_handler(struct intel_pxp *pxp, u16 iir)
+{
+ struct intel_gt *gt = pxp_to_gt(pxp);
+
+ if (GEM_WARN_ON(!intel_pxp_is_enabled(pxp)))
+ return;
+
+ lockdep_assert_held(&gt->irq_lock);
+
+ if (unlikely(!iir))
+ return;
+
+ if (iir & (GEN12_DISPLAY_PXP_STATE_TERMINATED_INTERRUPT |
+ GEN12_DISPLAY_APP_TERMINATED_PER_FW_REQ_INTERRUPT)) {
+ /* immediately mark PXP as inactive on termination */
+ intel_pxp_mark_termination_in_progress(pxp);
+ pxp->session_events |= PXP_TERMINATION_REQUEST;
+ }
+
+ if (iir & GEN12_DISPLAY_STATE_RESET_COMPLETE_INTERRUPT)
+ pxp->session_events |= PXP_TERMINATION_COMPLETE;
+
+ if (pxp->session_events)
+ queue_work(system_unbound_wq, &pxp->session_work);
+}
+
+static inline void __pxp_set_interrupts(struct intel_gt *gt, u32 interrupts)
+{
+ struct intel_uncore *uncore = gt->uncore;
+ const u32 mask = interrupts << 16;
+
+ intel_uncore_write(uncore, GEN11_CRYPTO_RSVD_INTR_ENABLE, mask);
+ intel_uncore_write(uncore, GEN11_CRYPTO_RSVD_INTR_MASK, ~mask);
+}
+
+static inline void pxp_irq_reset(struct intel_gt *gt)
+{
+ spin_lock_irq(&gt->irq_lock);
+ gen11_gt_reset_one_iir(gt, 0, GEN11_KCR);
+ spin_unlock_irq(&gt->irq_lock);
+}
+
+void intel_pxp_irq_enable(struct intel_pxp *pxp)
+{
+ struct intel_gt *gt = pxp_to_gt(pxp);
+
+ spin_lock_irq(&gt->irq_lock);
+
+ if (!pxp->irq_enabled)
+ WARN_ON_ONCE(gen11_gt_reset_one_iir(gt, 0, GEN11_KCR));
+
+ __pxp_set_interrupts(gt, GEN12_PXP_INTERRUPTS);
+ pxp->irq_enabled = true;
+
+ spin_unlock_irq(&gt->irq_lock);
+}
+
+void intel_pxp_irq_disable(struct intel_pxp *pxp)
+{
+ struct intel_gt *gt = pxp_to_gt(pxp);
+
+ /*
+ * We always need to submit a global termination when we re-enable the
+ * interrupts, so there is no need to make sure that the session state
+ * makes sense at the end of this function. Just make sure this is not
+ * called in a path were the driver consider the session as valid and
+ * doesn't call a termination on restart.
+ */
+ GEM_WARN_ON(intel_pxp_is_active(pxp));
+
+ spin_lock_irq(&gt->irq_lock);
+
+ pxp->irq_enabled = false;
+ __pxp_set_interrupts(gt, 0);
+
+ spin_unlock_irq(&gt->irq_lock);
+ intel_synchronize_irq(gt->i915);
+
+ pxp_irq_reset(gt);
+
+ flush_work(&pxp->session_work);
+}
diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_irq.h b/drivers/gpu/drm/i915/pxp/intel_pxp_irq.h
new file mode 100644
index 000000000000..8b5793654844
--- /dev/null
+++ b/drivers/gpu/drm/i915/pxp/intel_pxp_irq.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright(c) 2020, Intel Corporation. All rights reserved.
+ */
+
+#ifndef __INTEL_PXP_IRQ_H__
+#define __INTEL_PXP_IRQ_H__
+
+#include <linux/types.h>
+
+struct intel_pxp;
+
+#define GEN12_DISPLAY_PXP_STATE_TERMINATED_INTERRUPT BIT(1)
+#define GEN12_DISPLAY_APP_TERMINATED_PER_FW_REQ_INTERRUPT BIT(2)
+#define GEN12_DISPLAY_STATE_RESET_COMPLETE_INTERRUPT BIT(3)
+
+#define GEN12_PXP_INTERRUPTS \
+ (GEN12_DISPLAY_PXP_STATE_TERMINATED_INTERRUPT | \
+ GEN12_DISPLAY_APP_TERMINATED_PER_FW_REQ_INTERRUPT | \
+ GEN12_DISPLAY_STATE_RESET_COMPLETE_INTERRUPT)
+
+#ifdef CONFIG_DRM_I915_PXP
+void intel_pxp_irq_enable(struct intel_pxp *pxp);
+void intel_pxp_irq_disable(struct intel_pxp *pxp);
+void intel_pxp_irq_handler(struct intel_pxp *pxp, u16 iir);
+#else
+static inline void intel_pxp_irq_handler(struct intel_pxp *pxp, u16 iir)
+{
+}
+#endif
+
+#endif /* __INTEL_PXP_IRQ_H__ */
diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_session.c b/drivers/gpu/drm/i915/pxp/intel_pxp_session.c
index b8e24adeb1f3..67c30e534d50 100644
--- a/drivers/gpu/drm/i915/pxp/intel_pxp_session.c
+++ b/drivers/gpu/drm/i915/pxp/intel_pxp_session.c
@@ -48,7 +48,7 @@ static int pxp_wait_for_session_state(struct intel_pxp *pxp, u32 id, bool in_pla
return ret;
}

-int intel_pxp_create_arb_session(struct intel_pxp *pxp)
+static int pxp_create_arb_session(struct intel_pxp *pxp)
{
struct intel_gt *gt = pxp_to_gt(pxp);
int ret;
@@ -77,12 +77,13 @@ int intel_pxp_create_arb_session(struct intel_pxp *pxp)
return 0;
}

-int intel_pxp_terminate_arb_session_and_global(struct intel_pxp *pxp)
+static int pxp_terminate_arb_session_and_global(struct intel_pxp *pxp)
{
int ret;
struct intel_gt *gt = pxp_to_gt(pxp);

- pxp->arb_is_valid = false;
+ /* must mark termination in progress calling this function */
+ GEM_WARN_ON(pxp->arb_is_valid);

/* terminate the hw sessions */
ret = intel_pxp_terminate_session(pxp, ARB_SESSION);
@@ -101,3 +102,50 @@ int intel_pxp_terminate_arb_session_and_global(struct intel_pxp *pxp)

return ret;
}
+
+static void pxp_terminate(struct intel_pxp *pxp)
+{
+ int ret;
+
+ pxp->hw_state_invalidated = true;
+
+ /*
+ * if we fail to submit the termination there is no point in waiting for
+ * it to complete. PXP will be marked as non-active until the next
+ * termination is issued.
+ */
+ ret = pxp_terminate_arb_session_and_global(pxp);
+ if (ret)
+ complete_all(&pxp->termination);
+}
+
+static void pxp_terminate_complete(struct intel_pxp *pxp)
+{
+ /* Re-create the arb session after teardown handle complete */
+ if (fetch_and_zero(&pxp->hw_state_invalidated))
+ pxp_create_arb_session(pxp);
+
+ complete_all(&pxp->termination);
+}
+
+void intel_pxp_session_work(struct work_struct *work)
+{
+ struct intel_pxp *pxp = container_of(work, typeof(*pxp), session_work);
+ struct intel_gt *gt = pxp_to_gt(pxp);
+ u32 events = 0;
+
+ spin_lock_irq(&gt->irq_lock);
+ events = fetch_and_zero(&pxp->session_events);
+ spin_unlock_irq(&gt->irq_lock);
+
+ if (!events)
+ return;
+
+ if (events & PXP_TERMINATION_REQUEST) {
+ events &= ~PXP_TERMINATION_COMPLETE;
+ pxp_terminate(pxp);
+ }
+
+ if (events & PXP_TERMINATION_COMPLETE)
+ pxp_terminate_complete(pxp);
+}
diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_session.h b/drivers/gpu/drm/i915/pxp/intel_pxp_session.h
index 7354314b1cc4..ba4c9d2b94b7 100644
--- a/drivers/gpu/drm/i915/pxp/intel_pxp_session.h
+++ b/drivers/gpu/drm/i915/pxp/intel_pxp_session.h
@@ -8,9 +8,8 @@

#include <linux/types.h>

-struct intel_pxp;
+struct work_struct;

-int intel_pxp_create_arb_session(struct intel_pxp *pxp);
-int intel_pxp_terminate_arb_session_and_global(struct intel_pxp *pxp);
+void intel_pxp_session_work(struct work_struct *work);

#endif /* __INTEL_PXP_SESSION_H__ */
diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_tee.c b/drivers/gpu/drm/i915/pxp/intel_pxp_tee.c
index accbbf9aa6d1..494bd6b48514 100644
--- a/drivers/gpu/drm/i915/pxp/intel_pxp_tee.c
+++ b/drivers/gpu/drm/i915/pxp/intel_pxp_tee.c
@@ -80,6 +80,7 @@ static int i915_pxp_tee_component_bind(struct device *i915_kdev,
{
struct drm_i915_private *i915 = kdev_to_i915(i915_kdev);
struct intel_pxp *pxp = i915_dev_to_pxp(i915_kdev);
+ int ret;

mutex_lock(&pxp->tee_mutex);
pxp->pxp_component = data;
@@ -88,15 +89,14 @@ static int i915_pxp_tee_component_bind(struct device *i915_kdev,

/* the component is required to fully start the PXP HW */
intel_pxp_init_hw(pxp);
-
- if (!pxp->arb_is_valid) {
+ ret = intel_pxp_wait_for_arb_start(pxp);
+ if (ret) {
drm_err(&i915->drm, "Failed to create arb session during bind\n");
intel_pxp_fini_hw(pxp);
pxp->pxp_component = NULL;
- return -EIO;
}

- return 0;
+ return ret;
}

static void i915_pxp_tee_component_unbind(struct device *i915_kdev,
diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_types.h b/drivers/gpu/drm/i915/pxp/intel_pxp_types.h
index d393e46a7d98..5a170e43c959 100644
--- a/drivers/gpu/drm/i915/pxp/intel_pxp_types.h
+++ b/drivers/gpu/drm/i915/pxp/intel_pxp_types.h
@@ -6,8 +6,10 @@
#ifndef __INTEL_PXP_TYPES_H__
#define __INTEL_PXP_TYPES_H__

+#include <linux/completion.h>
#include <linux/mutex.h>
#include <linux/types.h>
+#include <linux/workqueue.h>

struct intel_context;
struct i915_pxp_component;
@@ -26,6 +28,22 @@ struct intel_pxp {
bool arb_is_valid;

struct mutex tee_mutex; /* protects the tee channel binding */
+
+ /*
+ * If the HW perceives an attack on the integrity of the encryption it
+ * will invalidate the keys and expect SW to re-initialize the session.
+ * We keep track of this state to make sure we only re-start the arb
+ * session when required.
+ */
+ bool hw_state_invalidated;
+
+ bool irq_enabled;
+ struct completion termination;
+
+ struct work_struct session_work;
+ u32 session_events; /* protected with gt->irq_lock */
+#define PXP_TERMINATION_REQUEST BIT(0)
+#define PXP_TERMINATION_COMPLETE BIT(1)
};

#endif /* __INTEL_PXP_TYPES_H__ */
--
2.25.1