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


    > + }
    > 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?
    > + * 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>


    Eric

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