Re: [PATCH v2] dmaengine: idxd: Only call idxd_enable_system_pasid() if succeeded in enabling SVA feature

Fenghua Yu
2022-06-26T05:06:09Z

Hi, Jerry,

On Sat, Jun 25, 2022 at 09:51:44PM -0700, Jerry Snitselaar wrote:
> On a Sapphire Rapids system if you boot without intel_iommu=on, the IDXD
s/you//

> driver will crash during probe in iommu_sva_bind_device().
....
> v2: Balance braces on if else block. Fix up commit description.

This change log should be moved after "---".

>
> Fixes: 42a1b73852c4 ("dmaengine: idxd: Separate user and kernel pasid enabling")
> Cc: Vinod Koul <vkoul@kernel.org>
> Cc: linux-kernel@vger.kernel.org
> Cc: Dave Jiang <dave.jiang@intel.com>
> Cc: Fenghua Yu <fenghua.yu@intel.com>
> Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>

Please put the bug report link here:

Link: https://lore.kernel.org/dmaengine/20220623170232.6whonfjuh3m5vcoy@cantor/

> ---

i.e. put the change log here:

v2: Balance braces on if else block. Fix up commit description.

> drivers/dma/idxd/init.c | 13 +++++++------
> 1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
> index 355fb3ef4cbf..aa3478257ddb 100644
> --- a/drivers/dma/idxd/init.c
> +++ b/drivers/dma/idxd/init.c
> @@ -512,15 +512,16 @@ static int idxd_probe(struct idxd_device *idxd)
> dev_dbg(dev, "IDXD reset complete\n");
>
> if (IS_ENABLED(CONFIG_INTEL_IDXD_SVM) && sva) {
> - if (iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_SVA))
> + if (iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_SVA)) {
> dev_warn(dev, "Unable to turn on user SVA feature.\n");
> - else
> + } else {
> set_bit(IDXD_FLAG_USER_PASID_ENABLED, &idxd->flags);
>
> - if (idxd_enable_system_pasid(idxd))
> - dev_warn(dev, "No in-kernel DMA with PASID.\n");
> - else
> - set_bit(IDXD_FLAG_PASID_ENABLED, &idxd->flags);
> + if (idxd_enable_system_pasid(idxd))
> + dev_warn(dev, "No in-kernel DMA with PASID.\n");
> + else
> + set_bit(IDXD_FLAG_PASID_ENABLED, &idxd->flags);
> + }
> } else if (!sva) {
> dev_warn(dev, "User forced SVA off via module param.\n");
> }
> --
> 2.36.1
>
Thanks.

-Fenghua