On Thu, Sep 28, 2023 at 03:55:47PM +0200, Niklas Schnelle wrote:
> Since commit 06cd555f73ca ("net/mlx5: split mlx5_cmd_init() to probe and
> reload routines") mlx5_cmd_init() is called in mlx5_mdev_init() which is
> called in probe_one() before mlx5_pci_init(). This is a problem because
> mlx5_pci_init() is where the DMA and coherent mask is set but
> mlx5_cmd_init() already does a dma_alloc_coherent(). Thus a DMA
> allocation is done during probe before the correct mask is set. This
> causes probe to fail initialization of the cmdif SW structs on s390x
> after that is converted to the common dma-iommu code. This is because on
> s390x DMA addresses below 4 GiB are reserved on current machines and
> unlike the old s390x specific DMA API implementation common code
> enforces DMA masks. Fix this by switching the order of the
> mlx5_mdev_init() and mlx5_pci_init() in probe_one().
>
> Link: https://lore.kernel.org/linux-iommu/cfc9e9128ed5571d2e36421e347301057662a09e.camel@xxxxxxxxxxxxx/
> Fixes: 06cd555f73ca ("net/mlx5: split mlx5_cmd_init() to probe and reload routines")
> Signed-off-by: Niklas Schnelle <schnelle@xxxxxxxxxxxxx>
> ---
> Note: I ran into this while testing the linked series for converting
> s390x to use dma-iommu. The existing s390x specific DMA API
> implementation doesn't respect DMA masks and is thus not affected
> despite of course also only supporting DMA addresses above 4 GiB.
> That said ConnectX VFs are the primary users of native PCI on s390x and
> we'd really like to get the DMA API conversion into v6.7 so this has
> high priority for us.
> ---
> drivers/net/ethernet/mellanox/mlx5/core/main.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c
> index 15561965d2af..06744dedd928 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/main.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c
> @@ -1908,10 +1908,6 @@ static int probe_one(struct pci_dev *pdev, const struct pci_device_id *id)
> goto adev_init_err;
> }
>
> - err = mlx5_mdev_init(dev, prof_sel);
> - if (err)
> - goto mdev_init_err;
> -
> err = mlx5_pci_init(dev, pdev, id);
> if (err) {
> mlx5_core_err(dev, "mlx5_pci_init failed with error code %d\n",
> @@ -1919,6 +1915,10 @@ static int probe_one(struct pci_dev *pdev, const struct pci_device_id *id)
> goto pci_init_err;
> }
>
> + err = mlx5_mdev_init(dev, prof_sel);
> + if (err)
> + goto mdev_init_err;
> +
I had something different in mind as I'm worry that call to pci_enable_device()
in mlx5_pci_init() before we finished FW command interface initialization is a bit
premature.
What about the following patch?
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c
index 15561965d2af..31f1d701116a 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c
@@ -905,12 +905,6 @@ static int mlx5_pci_init(struct mlx5_core_dev *dev, struct pci_dev *pdev,
pci_set_master(pdev);
- err = set_dma_caps(pdev);
- if (err) {
- mlx5_core_err(dev, "Failed setting DMA capabilities mask, aborting\n");
- goto err_clr_master;
- }
-
if (pci_enable_atomic_ops_to_root(pdev, PCI_EXP_DEVCAP2_ATOMIC_COMP32) &&
pci_enable_atomic_ops_to_root(pdev, PCI_EXP_DEVCAP2_ATOMIC_COMP64) &&
pci_enable_atomic_ops_to_root(pdev, PCI_EXP_DEVCAP2_ATOMIC_COMP128))
@@ -1908,9 +1902,15 @@ static int probe_one(struct pci_dev *pdev, const struct pci_device_id *id)
goto adev_init_err;
}
+ err = set_dma_caps(pdev);
+ if (err) {
+ mlx5_core_err(dev, "Failed setting DMA capabilities mask, aborting\n");
+ goto dma_cap_err;
+ }
+
err = mlx5_mdev_init(dev, prof_sel);
if (err)
- goto mdev_init_err;
+ goto dma_cap_err;
err = mlx5_pci_init(dev, pdev, id);
if (err) {
@@ -1942,7 +1942,7 @@ static int probe_one(struct pci_dev *pdev, const struct pci_device_id *id)
mlx5_pci_close(dev);
pci_init_err:
mlx5_mdev_uninit(dev);
-mdev_init_err:
+dma_cap_err:
mlx5_adev_idx_free(dev->priv.adev_idx);
adev_init_err:
mlx5_devlink_free(devlink);
Thanks
