Hi, > -----Original Message----- > From: Bing Zhao <[email protected]> > Sent: Friday, May 15, 2020 11:14 AM > To: Slava Ovsiienko <[email protected]>; Raslan Darawsheh > <[email protected]> > Cc: Ori Kam <[email protected]>; Matan Azrad <[email protected]>; > [email protected]; [email protected]; Dekel Peled <[email protected]> > Subject: [PATCH] net/mlx5: fix left shift extension of doorbell bitmap > > The doorbell record is organized with page and bitmap. When some new > doorbell needs to be associated with a queue, the bit will be set > in the bitmap to indicate the corresponding doorbell occupied. A > counter is used to record the number of doorbell occupied to speed > up the searching. > If the number reachs the maximal value of a pre-defined number of a > page, a new page will be allocated. If not, then the bitmap will be > checked to find a free one. > The LSHIFT and OR (AND NOT) operations are used to update the bitmap > of a page. But 1 will be treated as a signed integer when compiling. > When the shift number is 31, the shifted value will be considered as > negative. Then a wrong extension will be done when setting it to a > 64-bits variable. All the upper 32-bits will be set to 1 by such > extension. > Then a wrong offset value will be calculated because of this. The > next 64 bits will be also treated as the bitmap and get corrupted > through the bit set operation. > The immediate value 1 needs to be used as 64 bits width explicitly. > > Fixes: 21cae8580fd0 ("net/mlx5: allocate door-bells via DevX") > Cc: [email protected] > Cc: [email protected] > > Signed-off-by: Bing Zhao <[email protected]> > Acked-by: Viacheslav Ovsiienko <[email protected]> > --- > drivers/net/mlx5/mlx5.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/mlx5/mlx5.c b/drivers/net/mlx5/mlx5.c > index 1445809..ab4adec 100644 > --- a/drivers/net/mlx5/mlx5.c > +++ b/drivers/net/mlx5/mlx5.c > @@ -2174,7 +2174,7 @@ struct mlx5_flow_id_pool * > /* Find the first clear bit. */ > MLX5_ASSERT(i < MLX5_DBR_BITMAP_SIZE); > j = rte_bsf64(~page->dbr_bitmap[i]); > - page->dbr_bitmap[i] |= (1 << j); > + page->dbr_bitmap[i] |= (UINT64_C(1) << j); > page->dbr_count++; > *dbr_page = page; > return (((i * 64) + j) * sizeof(uint64_t)); > @@ -2219,7 +2219,7 @@ struct mlx5_flow_id_pool * > int i = offset / 64; > int j = offset % 64; > > - page->dbr_bitmap[i] &= ~(1 << j); > + page->dbr_bitmap[i] &= ~(UINT64_C(1) << j); > } > return ret; > } > -- > 1.8.3.1
Commit title changed to: net/mlx5: fix left shift extension of doorbell bitmap Patch applied to next-net-mlx, Kindest regards Raslan Darawsheh
