[PATCH 1/1] iommu/vt-d: Assign owner to the static identity domain

[PATCH 1/1] iommu/vt-d: Assign owner to the static identity domain

[Lu Baolu]

The idxd driver attaches the default domain to a PASID of the device to
perform kernel DMA using that PASID. The domain is attached to the
device's PASID through iommu_attach_device_pasid(), which checks if the
domain->owner matches the iommu_ops retrieved from the device. If they
do not match, it returns a failure.

        if (ops != domain->owner || pasid == IOMMU_NO_PASID)
                return -EINVAL;

The static identity domain implemented by the intel iommu driver doesn't
specify the domain owner. Therefore, kernel DMA with PASID doesn't work
for the idxd driver if the device translation mode is set to passthrough.

Fix this by specifying the domain owner for the static identity domain.

Fixes: 2031c469f816 ("iommu/vt-d: Add support for static identity domain")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220031
Cc: stable@vger.kernel.org
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel/iommu.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index cb0b993bebb4..63c9c97ccf69 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -4385,6 +4385,7 @@ static struct iommu_domain identity_domain = {
 		.attach_dev	= identity_domain_attach_dev,
 		.set_dev_pasid	= identity_domain_set_dev_pasid,
 	},
+	.owner = &intel_iommu_ops,
 };
 
 const struct iommu_ops intel_iommu_ops = {
-- 
2.43.0

Re: [PATCH 1/1] iommu/vt-d: Assign owner to the static identity domain

[Dave Jiang]

On 4/22/25 12:54 AM, Lu Baolu wrote:
> The idxd driver attaches the default domain to a PASID of the device to
> perform kernel DMA using that PASID. The domain is attached to the
> device's PASID through iommu_attach_device_pasid(), which checks if the
> domain->owner matches the iommu_ops retrieved from the device. If they
> do not match, it returns a failure.
> 
>         if (ops != domain->owner || pasid == IOMMU_NO_PASID)
>                 return -EINVAL;
> 
> The static identity domain implemented by the intel iommu driver doesn't
> specify the domain owner. Therefore, kernel DMA with PASID doesn't work
> for the idxd driver if the device translation mode is set to passthrough.
> 
> Fix this by specifying the domain owner for the static identity domain.
> 
> Fixes: 2031c469f816 ("iommu/vt-d: Add support for static identity domain")
> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220031
> Cc: stable@vger.kernel.org
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>

Reviewed-by: Dave Jiang <dave.jiang@intel.com>

> ---
>  drivers/iommu/intel/iommu.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index cb0b993bebb4..63c9c97ccf69 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -4385,6 +4385,7 @@ static struct iommu_domain identity_domain = {
>  		.attach_dev	= identity_domain_attach_dev,
>  		.set_dev_pasid	= identity_domain_set_dev_pasid,
>  	},
> +	.owner = &intel_iommu_ops,
>  };
>  
>  const struct iommu_ops intel_iommu_ops = {

Re: [PATCH 1/1] iommu/vt-d: Assign owner to the static identity domain

[Jason Gunthorpe]

On Tue, Apr 22, 2025 at 03:54:22PM +0800, Lu Baolu wrote:

> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index cb0b993bebb4..63c9c97ccf69 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -4385,6 +4385,7 @@ static struct iommu_domain identity_domain = {
>  		.attach_dev	= identity_domain_attach_dev,
>  		.set_dev_pasid	= identity_domain_set_dev_pasid,
>  	},
> +	.owner = &intel_iommu_ops,
>  };

Is this a systemic mistake in all the static domains in all the
drivers?

Maybe a bigger check is a more complete fix:

static bool iommu_domain_compatible(struct device *dev,
				    struct iommu_domain *domain)
{
	const struct iommu_ops *ops = dev_iommu_ops(dev);

	if (domain->owner == ops)
		return true;

	/* For static domains owner isn't set */
	if (ops->blocked_domain == domain || ops->identity_domain == domain)
		return true;
	return false;
}

Jason

Re: [PATCH 1/1] iommu/vt-d: Assign owner to the static identity domain

[Baolu Lu]

On 4/23/25 03:15, Jason Gunthorpe wrote:
> On Tue, Apr 22, 2025 at 03:54:22PM +0800, Lu Baolu wrote:
> 
>> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
>> index cb0b993bebb4..63c9c97ccf69 100644
>> --- a/drivers/iommu/intel/iommu.c
>> +++ b/drivers/iommu/intel/iommu.c
>> @@ -4385,6 +4385,7 @@ static struct iommu_domain identity_domain = {
>>   		.attach_dev	= identity_domain_attach_dev,
>>   		.set_dev_pasid	= identity_domain_set_dev_pasid,
>>   	},
>> +	.owner = &intel_iommu_ops,
>>   };
> 
> Is this a systemic mistake in all the static domains in all the
> drivers?

Yes. The owner field is not set for all static domains.

> Maybe a bigger check is a more complete fix:
> 
> static bool iommu_domain_compatible(struct device *dev,
> 				    struct iommu_domain *domain)
> {
> 	const struct iommu_ops *ops = dev_iommu_ops(dev);
> 
> 	if (domain->owner == ops)
> 		return true;
> 
> 	/* For static domains owner isn't set */
> 	if (ops->blocked_domain == domain || ops->identity_domain == domain)
> 		return true;
> 	return false;
> }

That's better. I will post a v2 accordingly.

> Jason

Thanks,
baolu