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 I had no choice but to sort of duplicate that functionality in
Panthor. That means we also need to keep that interval recorded in the VM.
Signed-off-by: Adrián Larumbe <[email protected]>
---
drivers/gpu/drm/panthor/panthor_mmu.c | 33 +++++++++++++++++++++++++++++++++
1 file changed, 33 insertions(+)
diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c
b/drivers/gpu/drm/panthor/panthor_mmu.c
index 31cc57029c12..5625f3d34031 100644
--- a/drivers/gpu/drm/panthor/panthor_mmu.c
+++ b/drivers/gpu/drm/panthor/panthor_mmu.c
@@ -301,6 +301,15 @@ struct panthor_vm {
/** @mm_lock: Lock protecting the @mm field. */
struct mutex mm_lock;
+ /** @kernel_va: VA-range reserved for kernel BOs. */
+ struct {
+ /** @kernel_va.start: Start of the VA-range for kernel BOs. */
+ u64 start;
+
+ /** @kernel_va.range: Size of the automatic VA-range for kernel
BOs. */
+ u64 range;
+ } kernel_va;
+
/** @kernel_auto_va: Automatic VA-range for kernel BOs. */
struct {
/** @kernel_auto_va.start: Start of the automatic VA-range for
kernel BOs. */
@@ -1309,6 +1318,24 @@ static int panthor_vm_op_ctx_prealloc_pts(struct
panthor_vm_op_ctx *op_ctx)
return 0;
}
+static bool
+panthor_vm_is_kernel_address(struct panthor_vm *vm,
+ const struct drm_panthor_vm_bind_op *op)
+{
+ u32 op_type = op->flags & DRM_PANTHOR_VM_BIND_OP_TYPE_MASK;
+ u64 end, kstart, krange, kend;
+
+ if (op_type == DRM_PANTHOR_VM_BIND_OP_TYPE_SYNC_ONLY)
+ return false;
+
+ end = op->va + op->size;
+ kstart = vm->kernel_va.start;
+ krange = vm->kernel_va.range;
+ kend = kstart + krange;
+
+ return krange && op->va < kend && kstart < end;
+}
+
#define PANTHOR_VM_BIND_OP_MAP_FLAGS \
(DRM_PANTHOR_VM_BIND_OP_MAP_READONLY | \
DRM_PANTHOR_VM_BIND_OP_MAP_NOEXEC | \
@@ -2891,6 +2918,8 @@ panthor_vm_create(struct panthor_device *ptdev, bool
for_mcu,
} else {
min_va = 0;
va_range = full_va_range;
+ vm->kernel_va.start = kernel_va_start;
+ vm->kernel_va.range = kernel_va_size;
}
mutex_init(&vm->mm_lock);
@@ -2981,6 +3010,10 @@ 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 intersect with kbo's reserved range */
+ if (panthor_vm_is_kernel_address(vm, op))
+ 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
