Am 20.12.24 um 12:31 schrieb Mika Kuoppala:
Implement debugger vm access for userptrs.
When bind is done, take ref to current task so that
we know from which vm the address was bound. Then during
debugger pread/pwrite we use this target task as
parameter to access the debuggee vm with access_process_vm().
This is based on suggestions from Thomas, Joonas and Simona.
Yeah that looks much saner to me. I still have a couple of comments on
the general approach, but I'm going to write that up after my vacation.
Regards,
Christian.
v2: need to add offset into vma (Dominik)
Cc: Matthew Brost <matthew.brost@xxxxxxxxx>
Cc: Andrzej Hajda <andrzej.hajda@xxxxxxxxx>
Cc: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
Cc: Dominik Grzegorzek <dominik.grzegorzek@xxxxxxxxx>
Cc: Christian König <christian.koenig@xxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: Simona Vetter <simona@xxxxxxxx>
Signed-off-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/xe/xe_eudebug.c | 13 +++++++++++++
drivers/gpu/drm/xe/xe_vm.c | 4 ++++
drivers/gpu/drm/xe/xe_vm.h | 28 +++++++++++++++++++++++++++-
drivers/gpu/drm/xe/xe_vm_types.h | 6 ++++++
4 files changed, 50 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/xe/xe_eudebug.c b/drivers/gpu/drm/xe/xe_eudebug.c
index 9d87df75348b..8b29192ab110 100644
--- a/drivers/gpu/drm/xe/xe_eudebug.c
+++ b/drivers/gpu/drm/xe/xe_eudebug.c
@@ -3074,6 +3074,19 @@ static int xe_eudebug_vma_access(struct xe_vma *vma, u64 offset_in_vma,
xe_bo_put(bo);
return ret;
+ } else if (xe_vma_is_userptr(vma)) {
+ struct xe_userptr *userptr = &to_userptr_vma(vma)->userptr;
+
+ /*
+ * XXX: access_remote_vm() would fit as userptr notifier has
+ * mm ref so we would not need to carry task ref at all.
+ * But access_remote_vm is not exported. access_process_vm()
+ * is exported so use it instead.
+ */
+ return access_process_vm(userptr->eudebug.task,
+ xe_vma_userptr(vma) + offset_in_vma,
+ buf, bytes,
+ write ? FOLL_WRITE : 0);
}
return -EINVAL;
diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
index 1cb21325d8dd..235ae2db5188 100644
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -999,6 +999,8 @@ static struct xe_vma *xe_vma_create(struct xe_vm *vm,
}
userptr->notifier_seq = LONG_MAX;
+
+ xe_eudebug_track_userptr_task(userptr);
}
xe_vm_get(vm);
@@ -1023,6 +1025,8 @@ static void xe_vma_destroy_late(struct xe_vma *vma)
if (userptr->sg)
xe_hmm_userptr_free_sg(uvma);
+ xe_eudebug_untrack_userptr_task(userptr);
+
/*
* Since userptr pages are not pinned, we can't remove
* the notifer until we're sure the GPU is not accessing
diff --git a/drivers/gpu/drm/xe/xe_vm.h b/drivers/gpu/drm/xe/xe_vm.h
index 23adb7442881..4334cf2b0d9d 100644
--- a/drivers/gpu/drm/xe/xe_vm.h
+++ b/drivers/gpu/drm/xe/xe_vm.h
@@ -274,9 +274,35 @@ static inline void vm_dbg(const struct drm_device *dev,
const char *format, ...)
{ /* noop */ }
#endif
-#endif
struct xe_vm_snapshot *xe_vm_snapshot_capture(struct xe_vm *vm);
void xe_vm_snapshot_capture_delayed(struct xe_vm_snapshot *snap);
void xe_vm_snapshot_print(struct xe_vm_snapshot *snap, struct drm_printer *p);
void xe_vm_snapshot_free(struct xe_vm_snapshot *snap);
+
+#if IS_ENABLED(CONFIG_DRM_XE_EUDEBUG)
+static inline void xe_eudebug_track_userptr_task(struct xe_userptr *userptr)
+{
+ /*
+ * We could use the mm which is on notifier. But
+ * the access_remote_vm() is not exported. Thus
+ * we get reference to task for access_process_vm()
+ */
+ userptr->eudebug.task = get_task_struct(current);
+}
+
+static inline void xe_eudebug_untrack_userptr_task(struct xe_userptr *userptr)
+{
+ put_task_struct(userptr->eudebug.task);
+}
+#else
+static inline void xe_eudebug_track_userptr_task(struct xe_userptr *userptr)
+{
+}
+
+static inline void xe_eudebug_untrack_userptr_task(struct xe_userptr *userptr)
+{
+}
+#endif /* CONFIG_DRM_XE_EUDEBUG */
+
+#endif
diff --git a/drivers/gpu/drm/xe/xe_vm_types.h b/drivers/gpu/drm/xe/xe_vm_types.h
index 557b047ebdd7..26176ccbcbbc 100644
--- a/drivers/gpu/drm/xe/xe_vm_types.h
+++ b/drivers/gpu/drm/xe/xe_vm_types.h
@@ -68,6 +68,12 @@ struct xe_userptr {
#if IS_ENABLED(CONFIG_DRM_XE_USERPTR_INVAL_INJECT)
u32 divisor;
#endif
+
+#if IS_ENABLED(CONFIG_DRM_XE_EUDEBUG)
+ struct {
+ struct task_struct *task;
+ } eudebug;
+#endif
};
struct xe_vma {
