2022-11-09 19:04:36

by Nicolin Chen

Subject: [PATCH v2] iommu/arm-smmu-v3: Restore prints in arm_smmu_attach_dev()

The prints for incompatible failures in arm_smmu_attach_dev() might be
still useful for error diagnosis. As VFIO and IOMMUFD would do testing
attach() call, having previous dev_err() isn't ideal either.

Add the prints back using dev_dbg().

Fixes: f4a147735793 ("iommu: Use EINVAL for incompatible device/domain in ->attach_dev")
Suggested-by: Will Deacon <[email protected]>
Reviewed-by: Jason Gunthorpe <[email protected]>
Signed-off-by: Nicolin Chen <[email protected]>
---
Changelog
v1->v2:
* Add "Fixes" line and Reviewed-by from Jason

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index ab160198edd6..076d3710b1fe 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2433,14 +2433,21 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
goto out_unlock;
}
} else if (smmu_domain->smmu != smmu) {
+ dev_dbg(dev, "cannot attach to SMMU %s (upstream of %s)\n",
+ dev_name(smmu_domain->smmu->dev), dev_name(smmu->dev));
ret = -EINVAL;
goto out_unlock;
} else if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1 &&
master->ssid_bits != smmu_domain->s1_cfg.s1cdmax) {
+ dev_dbg(dev,
+ "cannot attach to incompatible domain (%u SSID bits != %u)\n",
+ smmu_domain->s1_cfg.s1cdmax, master->ssid_bits);
ret = -EINVAL;
goto out_unlock;
} else if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1 &&
smmu_domain->stall_enabled != master->stall_enabled) {
+ dev_dbg(dev, "cannot attach to stall-%s domain\n",
+ smmu_domain->stall_enabled ? "enabled" : "disabled");
ret = -EINVAL;
goto out_unlock;
}
--
2.38.1

2022-11-14 14:25:30

by Will Deacon

Subject: Re: [PATCH v2] iommu/arm-smmu-v3: Restore prints in arm_smmu_attach_dev()

On Wed, Nov 09, 2022 at 10:46:36AM -0800, Nicolin Chen wrote:
> The prints for incompatible failures in arm_smmu_attach_dev() might be
> still useful for error diagnosis. As VFIO and IOMMUFD would do testing
> attach() call, having previous dev_err() isn't ideal either.
>
> Add the prints back using dev_dbg().
>
> Fixes: f4a147735793 ("iommu: Use EINVAL for incompatible device/domain in ->attach_dev")
> Suggested-by: Will Deacon <[email protected]>
> Reviewed-by: Jason Gunthorpe <[email protected]>
> Signed-off-by: Nicolin Chen <[email protected]>
> ---
> Changelog
> v1->v2:
> * Add "Fixes" line and Reviewed-by from Jason
>
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> index ab160198edd6..076d3710b1fe 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -2433,14 +2433,21 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
> goto out_unlock;
> }
> } else if (smmu_domain->smmu != smmu) {
> + dev_dbg(dev, "cannot attach to SMMU %s (upstream of %s)\n",
> + dev_name(smmu_domain->smmu->dev), dev_name(smmu->dev));
> ret = -EINVAL;
> goto out_unlock;
> } else if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1 &&
> master->ssid_bits != smmu_domain->s1_cfg.s1cdmax) {
> + dev_dbg(dev,
> + "cannot attach to incompatible domain (%u SSID bits != %u)\n",
> + smmu_domain->s1_cfg.s1cdmax, master->ssid_bits);
> ret = -EINVAL;
> goto out_unlock;
> } else if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1 &&
> smmu_domain->stall_enabled != master->stall_enabled) {
> + dev_dbg(dev, "cannot attach to stall-%s domain\n",
> + smmu_domain->stall_enabled ? "enabled" : "disabled");
> ret = -EINVAL;
> goto out_unlock;

Thanks!

Acked-by: Will Deacon <[email protected]>

Will