When a VM is created, caller has to specify the range of the address space
carve-out set aside for mapping kernel BO's. That means vm_bind mappings of
UM-exposed BO's should not intersect with that region, but at the moment
we're not checking this.
At first, I thought of giving these values to drm_gpuvm_init() through its
reserve_{offset, range} arguments, but it turns out that is meant for VM
address spans that are not managed through the usual drm_gpuvm split/merge
circuit, so storing the end of the user VA range at VM creation time and
doing a quick check in the vm_bind ioctl path was the simplest workaround.
Signed-off-by: Adrián Larumbe <[email protected]>
---
drivers/gpu/drm/panthor/panthor_mmu.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c
b/drivers/gpu/drm/panthor/panthor_mmu.c
index 31cc57029c12..a8de4fe6b231 100644
--- a/drivers/gpu/drm/panthor/panthor_mmu.c
+++ b/drivers/gpu/drm/panthor/panthor_mmu.c
@@ -310,6 +310,9 @@ struct panthor_vm {
u64 end;
} kernel_auto_va;
+ /** @user_va_end: Last VA in the address range VM users can map objects
against. */
+ u64 user_va_end;
+
/** @as: Address space related fields. */
struct {
/**
@@ -2893,6 +2896,8 @@ panthor_vm_create(struct panthor_device *ptdev, bool
for_mcu,
va_range = full_va_range;
}
+ vm->user_va_end = kernel_va_start - 1;
+
mutex_init(&vm->mm_lock);
drm_mm_init(&vm->mm, kernel_va_start, kernel_va_size);
vm->kernel_auto_va.start = auto_kernel_va_start;
@@ -2981,6 +2986,10 @@ panthor_vm_bind_prepare_op_ctx(struct drm_file *file,
if (!IS_ALIGNED(op->va | op->size | op->bo_offset, vm_pgsz))
return -EINVAL;
+ /* We don't allow mappings that overlap with kbo's reserved range */
+ if (op->va + op->size > vm->user_va_end)
+ return -EINVAL;
+
switch (op->flags & DRM_PANTHOR_VM_BIND_OP_TYPE_MASK) {
case DRM_PANTHOR_VM_BIND_OP_TYPE_MAP:
if (!(op->flags & DRM_PANTHOR_VM_BIND_OP_MAP_SPARSE)) {
--
2.54.0
