[PATCH] drm/imagination: Hold drm_gem_gpuva lock for unmap

From: Brendan King via B4 Relay
Date: Mon Feb 03 2025 - 10:33:41 EST

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From: Brendan King <Brendan.King@xxxxxxxxxx>

Avoid a warning from drm_gem_gpuva_assert_lock_held in drm_gpuva_unlink.

The Imagination driver uses the GEM object reservation lock to protect
the gpuva list, but the GEM object was not always known in the code
paths that ended up calling drm_gpuva_unlink. When the GEM object isn't
known, it is found by calling drm_gpuva_find to lookup the object
associated with a given virtual address range, or by calling
drm_gpuva_find_first when removing all mappings.

Signed-off-by: Brendan King <brendan.king@xxxxxxxxxx>
---
drivers/gpu/drm/imagination/pvr_fw_meta.c | 6 +-
drivers/gpu/drm/imagination/pvr_vm.c | 134 ++++++++++++++++++++++++------
drivers/gpu/drm/imagination/pvr_vm.h | 3 +
3 files changed, 115 insertions(+), 28 deletions(-)

diff --git a/drivers/gpu/drm/imagination/pvr_fw_meta.c b/drivers/gpu/drm/imagination/pvr_fw_meta.c
index c39beb70c3173ebdab13b4e810ce5d9a3419f0ba..6d13864851fc2e83bdaa94f16435b97841e5de94 100644
--- a/drivers/gpu/drm/imagination/pvr_fw_meta.c
+++ b/drivers/gpu/drm/imagination/pvr_fw_meta.c
@@ -527,8 +527,10 @@ pvr_meta_vm_map(struct pvr_device *pvr_dev, struct pvr_fw_object *fw_obj)
static void
pvr_meta_vm_unmap(struct pvr_device *pvr_dev, struct pvr_fw_object *fw_obj)
{
- pvr_vm_unmap(pvr_dev->kernel_vm_ctx, fw_obj->fw_mm_node.start,
- fw_obj->fw_mm_node.size);
+ struct pvr_gem_object *pvr_obj = fw_obj->gem;
+
+ pvr_vm_unmap_obj(pvr_dev->kernel_vm_ctx, pvr_obj,
+ fw_obj->fw_mm_node.start, fw_obj->fw_mm_node.size);
}

static bool
diff --git a/drivers/gpu/drm/imagination/pvr_vm.c b/drivers/gpu/drm/imagination/pvr_vm.c
index 363f885a709826efa3d45a906c5f65131f7ed7b9..2896fa7501b1ccddaae48b212b6a724d152df9f2 100644
--- a/drivers/gpu/drm/imagination/pvr_vm.c
+++ b/drivers/gpu/drm/imagination/pvr_vm.c
@@ -293,8 +293,9 @@ pvr_vm_bind_op_map_init(struct pvr_vm_bind_op *bind_op,

static int
pvr_vm_bind_op_unmap_init(struct pvr_vm_bind_op *bind_op,
- struct pvr_vm_context *vm_ctx, u64 device_addr,
- u64 size)
+ struct pvr_vm_context *vm_ctx,
+ struct pvr_gem_object *pvr_obj,
+ u64 device_addr, u64 size)
{
int err;

@@ -318,6 +319,7 @@ pvr_vm_bind_op_unmap_init(struct pvr_vm_bind_op *bind_op,
goto err_bind_op_fini;
}

+ bind_op->pvr_obj = pvr_obj;
bind_op->vm_ctx = vm_ctx;
bind_op->device_addr = device_addr;
bind_op->size = size;
@@ -597,20 +599,6 @@ pvr_vm_create_context(struct pvr_device *pvr_dev, bool is_userspace_context)
return ERR_PTR(err);
}

-/**
- * pvr_vm_unmap_all() - Unmap all mappings associated with a VM context.
- * @vm_ctx: Target VM context.
- *
- * This function ensures that no mappings are left dangling by unmapping them
- * all in order of ascending device-virtual address.
- */
-void
-pvr_vm_unmap_all(struct pvr_vm_context *vm_ctx)
-{
- WARN_ON(pvr_vm_unmap(vm_ctx, vm_ctx->gpuvm_mgr.mm_start,
- vm_ctx->gpuvm_mgr.mm_range));
-}
-
/**
* pvr_vm_context_release() - Teardown a VM context.
* @ref_count: Pointer to reference counter of the VM context.
@@ -703,11 +691,7 @@ pvr_vm_lock_extra(struct drm_gpuvm_exec *vm_exec)
struct pvr_vm_bind_op *bind_op = vm_exec->extra.priv;
struct pvr_gem_object *pvr_obj = bind_op->pvr_obj;

- /* Unmap operations don't have an object to lock. */
- if (!pvr_obj)
- return 0;
-
- /* Acquire lock on the GEM being mapped. */
+ /* Acquire lock on the GEM object being mapped/unmapped. */
return drm_exec_lock_obj(&vm_exec->exec, gem_from_pvr_gem(pvr_obj));
}

@@ -772,8 +756,10 @@ pvr_vm_map(struct pvr_vm_context *vm_ctx, struct pvr_gem_object *pvr_obj,
}

/**
- * pvr_vm_unmap() - Unmap an already mapped section of device-virtual memory.
+ * pvr_vm_unmap_obj_locked() - Unmap an already mapped section of device-virtual
+ * memory.
* @vm_ctx: Target VM context.
+ * @pvr_obj: Target PowerVR memory object.
* @device_addr: Virtual device address at the start of the target mapping.
* @size: Size of the target mapping.
*
@@ -784,9 +770,13 @@ pvr_vm_map(struct pvr_vm_context *vm_ctx, struct pvr_gem_object *pvr_obj,
* * Any error encountered while performing internal operations required to
* destroy the mapping (returned from pvr_vm_gpuva_unmap or
* pvr_vm_gpuva_remap).
+ *
+ * The vm_ctx->lock must be held when calling this function.
*/
-int
-pvr_vm_unmap(struct pvr_vm_context *vm_ctx, u64 device_addr, u64 size)
+static int
+pvr_vm_unmap_obj_locked(struct pvr_vm_context *vm_ctx,
+ struct pvr_gem_object *pvr_obj,
+ u64 device_addr, u64 size)
{
struct pvr_vm_bind_op bind_op = {0};
struct drm_gpuvm_exec vm_exec = {
@@ -799,11 +789,13 @@ pvr_vm_unmap(struct pvr_vm_context *vm_ctx, u64 device_addr, u64 size)
},
};

- int err = pvr_vm_bind_op_unmap_init(&bind_op, vm_ctx, device_addr,
- size);
+ int err = pvr_vm_bind_op_unmap_init(&bind_op, vm_ctx, pvr_obj,
+ device_addr, size);
if (err)
return err;

+ pvr_gem_object_get(pvr_obj);
+
err = drm_gpuvm_exec_lock(&vm_exec);
if (err)
goto err_cleanup;
@@ -818,6 +810,96 @@ pvr_vm_unmap(struct pvr_vm_context *vm_ctx, u64 device_addr, u64 size)
return err;
}

+/**
+ * pvr_vm_unmap_obj() - Unmap an already mapped section of device-virtual
+ * memory.
+ * @vm_ctx: Target VM context.
+ * @pvr_obj: Target PowerVR memory object.
+ * @device_addr: Virtual device address at the start of the target mapping.
+ * @size: Size of the target mapping.
+ *
+ * Return:
+ * * 0 on success,
+ * * Any error encountered by pvr_vm_unmap_obj_locked.
+ */
+int
+pvr_vm_unmap_obj(struct pvr_vm_context *vm_ctx, struct pvr_gem_object *pvr_obj,
+ u64 device_addr, u64 size)
+{
+ int err;
+
+ mutex_lock(&vm_ctx->lock);
+ err = pvr_vm_unmap_obj_locked(vm_ctx, pvr_obj, device_addr, size);
+ mutex_unlock(&vm_ctx->lock);
+
+ return err;
+}
+
+/**
+ * pvr_vm_unmap() - Unmap an already mapped section of device-virtual memory.
+ * @vm_ctx: Target VM context.
+ * @device_addr: Virtual device address at the start of the target mapping.
+ * @size: Size of the target mapping.
+ *
+ * Return:
+ * * 0 on success,
+ * * Any error encountered by drm_gpuva_find,
+ * * Any error encountered by pvr_vm_unmap_obj_locked.
+ */
+int
+pvr_vm_unmap(struct pvr_vm_context *vm_ctx, u64 device_addr, u64 size)
+{
+ struct pvr_gem_object *pvr_obj;
+ struct drm_gpuva *va;
+ int err;
+
+ mutex_lock(&vm_ctx->lock);
+
+ va = drm_gpuva_find(&vm_ctx->gpuvm_mgr, device_addr, size);
+ if (va) {
+ pvr_obj = gem_to_pvr_gem(va->gem.obj);
+ err = pvr_vm_unmap_obj_locked(vm_ctx, pvr_obj,
+ va->va.addr, va->va.range);
+ } else {
+ err = -ENOENT;
+ }
+
+ mutex_unlock(&vm_ctx->lock);
+
+ return err;
+}
+
+/**
+ * pvr_vm_unmap_all() - Unmap all mappings associated with a VM context.
+ * @vm_ctx: Target VM context.
+ *
+ * This function ensures that no mappings are left dangling by unmapping them
+ * all in order of ascending device-virtual address.
+ */
+void
+pvr_vm_unmap_all(struct pvr_vm_context *vm_ctx)
+{
+ mutex_lock(&vm_ctx->lock);
+
+ for (;;) {
+ struct pvr_gem_object *pvr_obj;
+ struct drm_gpuva *va;
+
+ va = drm_gpuva_find_first(&vm_ctx->gpuvm_mgr,
+ vm_ctx->gpuvm_mgr.mm_start,
+ vm_ctx->gpuvm_mgr.mm_range);
+ if (!va)
+ break;
+
+ pvr_obj = gem_to_pvr_gem(va->gem.obj);
+
+ WARN_ON(pvr_vm_unmap_obj_locked(vm_ctx, pvr_obj,
+ va->va.addr, va->va.range));
+ }
+
+ mutex_unlock(&vm_ctx->lock);
+}
+
/* Static data areas are determined by firmware. */
static const struct drm_pvr_static_data_area static_data_areas[] = {
{
diff --git a/drivers/gpu/drm/imagination/pvr_vm.h b/drivers/gpu/drm/imagination/pvr_vm.h
index 79406243617c1f025c0119eb8deeaa13c0415586..b0528dffa7f1ba4342c98c2abd7fac31d254d0e7 100644
--- a/drivers/gpu/drm/imagination/pvr_vm.h
+++ b/drivers/gpu/drm/imagination/pvr_vm.h
@@ -38,6 +38,9 @@ struct pvr_vm_context *pvr_vm_create_context(struct pvr_device *pvr_dev,
int pvr_vm_map(struct pvr_vm_context *vm_ctx,
struct pvr_gem_object *pvr_obj, u64 pvr_obj_offset,
u64 device_addr, u64 size);
+int pvr_vm_unmap_obj(struct pvr_vm_context *vm_ctx,
+ struct pvr_gem_object *pvr_obj,
+ u64 device_addr, u64 size);
int pvr_vm_unmap(struct pvr_vm_context *vm_ctx, u64 device_addr, u64 size);
void pvr_vm_unmap_all(struct pvr_vm_context *vm_ctx);

---
base-commit: 3ab334814dc7dff39075e055e12847d51878916e
change-id: 20250203-hold-drm_gem_gpuva-lock-for-unmap-da4338395b23

Best regards,
--
Brendan King <Brendan.King@xxxxxxxxxx>

Next message: Krzysztof Kozlowski: "Re: [PATCH] dt-bindings: display: ti: Fix compatible for am62a7 dss"
Previous message: Brendan King via B4 Relay: "[PATCH] drm/imagination: avoid deadlock on fence release"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]