Re: [PATCH v2] drm/xe/xe_migrate: Cast to output precision before multiplying operands

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Mon, Apr 01, 2024 at 11:23:00PM +0530, Himal Prasad Ghimiray wrote:
> Addressing potential overflow in result of  multiplication of two lower
> precision (u32) operands before widening it to higher precision
> (u64).
> 
> -v2
> Fix commit message and description. (Rodrigo)
> 
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

pushing soon...

> ---
>  drivers/gpu/drm/xe/xe_migrate.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_migrate.c b/drivers/gpu/drm/xe/xe_migrate.c
> index ee1bb938c493..2ba4fb9511f6 100644
> --- a/drivers/gpu/drm/xe/xe_migrate.c
> +++ b/drivers/gpu/drm/xe/xe_migrate.c
> @@ -227,7 +227,7 @@ static int xe_migrate_prepare_vm(struct xe_tile *tile, struct xe_migrate *m,
>  		if (vm->flags & XE_VM_FLAG_64K && level == 1)
>  			flags = XE_PDE_64K;
>  
> -		entry = vm->pt_ops->pde_encode_bo(bo, map_ofs + (level - 1) *
> +		entry = vm->pt_ops->pde_encode_bo(bo, map_ofs + (u64)(level - 1) *
>  						  XE_PAGE_SIZE, pat_index);
>  		xe_map_wr(xe, &bo->vmap, map_ofs + XE_PAGE_SIZE * level, u64,
>  			  entry | flags);
> @@ -235,7 +235,7 @@ static int xe_migrate_prepare_vm(struct xe_tile *tile, struct xe_migrate *m,
>  
>  	/* Write PDE's that point to our BO. */
>  	for (i = 0; i < num_entries - num_level; i++) {
> -		entry = vm->pt_ops->pde_encode_bo(bo, i * XE_PAGE_SIZE,
> +		entry = vm->pt_ops->pde_encode_bo(bo, (u64)i * XE_PAGE_SIZE,
>  						  pat_index);
>  
>  		xe_map_wr(xe, &bo->vmap, map_ofs + XE_PAGE_SIZE +
> @@ -291,7 +291,7 @@ static int xe_migrate_prepare_vm(struct xe_tile *tile, struct xe_migrate *m,
>  #define VM_SA_UPDATE_UNIT_SIZE		(XE_PAGE_SIZE / NUM_VMUSA_UNIT_PER_PAGE)
>  #define NUM_VMUSA_WRITES_PER_UNIT	(VM_SA_UPDATE_UNIT_SIZE / sizeof(u64))
>  	drm_suballoc_manager_init(&m->vm_update_sa,
> -				  (map_ofs / XE_PAGE_SIZE - NUM_KERNEL_PDE) *
> +				  (size_t)(map_ofs / XE_PAGE_SIZE - NUM_KERNEL_PDE) *
>  				  NUM_VMUSA_UNIT_PER_PAGE, 0);
>  
>  	m->pt_bo = bo;
> @@ -490,7 +490,7 @@ static void emit_pte(struct xe_migrate *m,
>  	struct xe_vm *vm = m->q->vm;
>  	u16 pat_index;
>  	u32 ptes;
> -	u64 ofs = at_pt * XE_PAGE_SIZE;
> +	u64 ofs = (u64)at_pt * XE_PAGE_SIZE;
>  	u64 cur_ofs;
>  
>  	/* Indirect access needs compression enabled uncached PAT index */
> -- 
> 2.25.1
>