[PATCH] vdpa/mlx5: Fix MQ to support non power of two num queues

From: Eli Cohen
Date: Mon Sep 12 2022 - 08:50:36 EST


RQT objects require that a power of two value be configured for both
rqt_max_size and rqt_actual size.

For create_rqt, make sure to round up to the power of two the value of
given by the user who created the vdpa device and given by
ndev->rqt_size. The actual size is also rounded up to the power of two
using the current number of VQs given by ndev->cur_num_vqs.

Same goes with modify_rqt where we need to make sure act size is power
of two based on the new number of QPs.

Without this patch, attempt to create a device with non power of two QPs
would result in error from firmware.

Fixes: 52893733f2c5 ("vdpa/mlx5: Add multiqueue support")
Signed-off-by: Eli Cohen <elic@xxxxxxxxxx>
---
drivers/vdpa/mlx5/net/mlx5_vnet.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index ed100a35e596..90913365def4 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -1320,6 +1320,8 @@ static void teardown_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *

static int create_rqt(struct mlx5_vdpa_net *ndev)
{
+ int rqt_table_size = roundup_pow_of_two(ndev->rqt_size);
+ int act_sz = roundup_pow_of_two(ndev->cur_num_vqs / 2);
__be32 *list;
void *rqtc;
int inlen;
@@ -1327,7 +1329,7 @@ static int create_rqt(struct mlx5_vdpa_net *ndev)
int i, j;
int err;

- inlen = MLX5_ST_SZ_BYTES(create_rqt_in) + ndev->rqt_size * MLX5_ST_SZ_BYTES(rq_num);
+ inlen = MLX5_ST_SZ_BYTES(create_rqt_in) + rqt_table_size * MLX5_ST_SZ_BYTES(rq_num);
in = kzalloc(inlen, GFP_KERNEL);
if (!in)
return -ENOMEM;
@@ -1336,12 +1338,12 @@ static int create_rqt(struct mlx5_vdpa_net *ndev)
rqtc = MLX5_ADDR_OF(create_rqt_in, in, rqt_context);

MLX5_SET(rqtc, rqtc, list_q_type, MLX5_RQTC_LIST_Q_TYPE_VIRTIO_NET_Q);
- MLX5_SET(rqtc, rqtc, rqt_max_size, ndev->rqt_size);
+ MLX5_SET(rqtc, rqtc, rqt_max_size, rqt_table_size);
list = MLX5_ADDR_OF(rqtc, rqtc, rq_num[0]);
- for (i = 0, j = 0; i < ndev->rqt_size; i++, j += 2)
+ for (i = 0, j = 0; i < act_sz; i++, j += 2)
list[i] = cpu_to_be32(ndev->vqs[j % ndev->cur_num_vqs].virtq_id);

- MLX5_SET(rqtc, rqtc, rqt_actual_size, ndev->rqt_size);
+ MLX5_SET(rqtc, rqtc, rqt_actual_size, act_sz);
err = mlx5_vdpa_create_rqt(&ndev->mvdev, in, inlen, &ndev->res.rqtn);
kfree(in);
if (err)
@@ -1354,6 +1356,7 @@ static int create_rqt(struct mlx5_vdpa_net *ndev)

static int modify_rqt(struct mlx5_vdpa_net *ndev, int num)
{
+ int act_sz = roundup_pow_of_two(num / 2);
__be32 *list;
void *rqtc;
int inlen;
@@ -1361,7 +1364,7 @@ static int modify_rqt(struct mlx5_vdpa_net *ndev, int num)
int i, j;
int err;

- inlen = MLX5_ST_SZ_BYTES(modify_rqt_in) + ndev->rqt_size * MLX5_ST_SZ_BYTES(rq_num);
+ inlen = MLX5_ST_SZ_BYTES(modify_rqt_in) + act_sz * MLX5_ST_SZ_BYTES(rq_num);
in = kzalloc(inlen, GFP_KERNEL);
if (!in)
return -ENOMEM;
@@ -1372,10 +1375,10 @@ static int modify_rqt(struct mlx5_vdpa_net *ndev, int num)
MLX5_SET(rqtc, rqtc, list_q_type, MLX5_RQTC_LIST_Q_TYPE_VIRTIO_NET_Q);

list = MLX5_ADDR_OF(rqtc, rqtc, rq_num[0]);
- for (i = 0, j = 0; i < ndev->rqt_size; i++, j += 2)
+ for (i = 0, j = 0; i < act_sz; i++, j = j + 2)
list[i] = cpu_to_be32(ndev->vqs[j % num].virtq_id);

- MLX5_SET(rqtc, rqtc, rqt_actual_size, ndev->rqt_size);
+ MLX5_SET(rqtc, rqtc, rqt_actual_size, act_sz);
err = mlx5_vdpa_modify_rqt(&ndev->mvdev, in, inlen, ndev->res.rqtn);
kfree(in);
if (err)
--
2.35.1