Re: [PATCH v6 06/15] iommu/vt-d: Support setting ioasid set to domain

Auger Eric
2020-08-16T12:42:37Z

On 8/14/20 10:04 AM, Liu, Yi L wrote:
> Hi Eric,
>
>> From: Auger Eric <eric.auger@redhat.com>
>> Sent: Thursday, August 13, 2020 11:07 PM
>>
>> Hi Yi,
>>
>> On 7/28/20 8:27 AM, Liu Yi L wrote:
>>> From IOMMU p.o.v., PASIDs allocated and managed by external components
>>> (e.g. VFIO) will be passed in for gpasid_bind/unbind operation. IOMMU
>>> needs some knowledge to check the PASID ownership, hence add an
>>> interface for those components to tell the PASID owner.
>>>
>>> In latest kernel design, PASID ownership is managed by IOASID set
>>> where the PASID is allocated from. This patch adds support for setting
>>> ioasid set ID to the domains used for nesting/vSVA. Subsequent SVA
>>> operations will check the PASID against its IOASID set for proper ownership.
>>>
>>> Cc: Kevin Tian <kevin.tian@intel.com>
>>> CC: Jacob Pan <jacob.jun.pan@linux.intel.com>
>>> Cc: Alex Williamson <alex.williamson@redhat.com>
>>> Cc: Eric Auger <eric.auger@redhat.com>
>>> Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
>>> Cc: Joerg Roedel <joro@8bytes.org>
>>> Cc: Lu Baolu <baolu.lu@linux.intel.com>
>>> Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
>>> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
>>> ---
>>> v5 -> v6:
>>> *) address comments against v5 from Eric Auger.
>>>
>>> v4 -> v5:
>>> *) address comments from Eric Auger.
>>> ---
>>> drivers/iommu/intel/iommu.c | 23 +++++++++++++++++++++++
>>> include/linux/intel-iommu.h | 4 ++++
>>> include/linux/iommu.h | 1 +
>>> 3 files changed, 28 insertions(+)
>>>
>>> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
>>> index ed4b71c..b2fe54e 100644
>>> --- a/drivers/iommu/intel/iommu.c
>>> +++ b/drivers/iommu/intel/iommu.c
>>> @@ -1793,6 +1793,7 @@ static struct dmar_domain *alloc_domain(int flags)
>>> if (first_level_by_default())
>>> domain->flags |= DOMAIN_FLAG_USE_FIRST_LEVEL;
>>> domain->has_iotlb_device = false;
>>> + domain->ioasid_sid = INVALID_IOASID_SET;
>>> INIT_LIST_HEAD(&domain->devices);
>>>
>>> return domain;
>>> @@ -6040,6 +6041,28 @@ intel_iommu_domain_set_attr(struct iommu_domain
>> *domain,
>>> }
>>> spin_unlock_irqrestore(&device_domain_lock, flags);
>>> break;
>>> + case DOMAIN_ATTR_IOASID_SID:
>>> + {
>>> + int sid = *(int *)data;
>>
>>> +
>>> + spin_lock_irqsave(&device_domain_lock, flags);
>>> + if (!(dmar_domain->flags & DOMAIN_FLAG_NESTING_MODE)) {
>>> + ret = -ENODEV;
>>> + spin_unlock_irqrestore(&device_domain_lock, flags);
>>> + break;
>>> + }
>>> + if (dmar_domain->ioasid_sid != INVALID_IOASID_SET &&
>>> + dmar_domain->ioasid_sid != sid) {
>>> + pr_warn_ratelimited("multi ioasid_set (%d:%d) setting",
>>> + dmar_domain->ioasid_sid, sid);
>>> + ret = -EBUSY;
>>> + spin_unlock_irqrestore(&device_domain_lock, flags);
>>> + break;
>>> + }
>>> + dmar_domain->ioasid_sid = sid;
>>> + spin_unlock_irqrestore(&device_domain_lock, flags);
>>> + break;
>> nit: Adding a small helper
>> int__set_ioasid_sid(struct dmar_domain *dmar_domain, int sid_id)
>>
>> may simplify the lock handling
>
> ok. will do.
>
>>
>>> + }
>>> default:
>>> ret = -EINVAL;
>>> break;
>>> diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
>>> index 3f23c26..0d0ab32 100644
>>> --- a/include/linux/intel-iommu.h
>>> +++ b/include/linux/intel-iommu.h
>>> @@ -549,6 +549,10 @@ struct dmar_domain {
>>> 2 == 1GiB, 3 == 512GiB, 4 == 1TiB */
>>> u64 max_addr; /* maximum mapped address */
>>>
>>> + int ioasid_sid; /*
>>> + * the ioasid set which tracks all
>> id of the ioasid set?
>
> should be ioasid_set. however, ioasid_alloc_set() returns sid in Jacob's
> series. but, I heard from Jacob, he will remove ioasid_sid, and return
> ioasid_set. so I will modify it once his patch is sent out.
>
> https://lore.kernel.org/linux-iommu/1585158931-1825-4-git-send-email-jacob.jun.pan@linux.intel.com/

OK

Thanks

Eric
>
>>> + * PASIDs used by the domain.
>>> + */
>>> int default_pasid; /*
>>> * The default pasid used for non-SVM
>>> * traffic on mediated devices.
>>> diff --git a/include/linux/iommu.h b/include/linux/iommu.h index
>>> 4a02c9e..b1ff702 100644
>>> --- a/include/linux/iommu.h
>>> +++ b/include/linux/iommu.h
>>> @@ -124,6 +124,7 @@ enum iommu_attr {
>>> DOMAIN_ATTR_FSL_PAMUV1,
>>> DOMAIN_ATTR_NESTING, /* two stages of translation */
>>> DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE,
>>> + DOMAIN_ATTR_IOASID_SID,
>>> DOMAIN_ATTR_MAX,
>>> };
>>>
>>>
>> Besides
>> Reviewed-by: Eric Auger <eric.auger@redhat.com>
>
> thanks :-)
>
> Regards,
> Yi Liu
>
>>
>> Eric
>