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    SubjectRe: [PATCH v4 4/8] iommu/vt-d: Attach/detach domains in auxiliary mode
    Date
    Hi Lu,

    On 11/5/18 8:34 AM, Lu Baolu wrote:
    > When multiple domains per device has been enabled by the
    > device driver, the device will tag the default PASID for
    > the domain to all DMA traffics out of the subset of this
    > device; and the IOMMU should translate the DMA requests
    > in PASID granularity.
    >
    > This extends the intel_iommu_attach/detach_device() ops
    > to support managing PASID granular translation structures
    > when the device driver has enabled multiple domains per
    > device.
    >
    > Cc: Ashok Raj <ashok.raj@intel.com>
    > Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
    > Cc: Kevin Tian <kevin.tian@intel.com>
    > Signed-off-by: Sanjay Kumar <sanjay.k.kumar@intel.com>
    > Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
    > Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
    > ---
    > drivers/iommu/intel-iommu.c | 192 +++++++++++++++++++++++++++++++-----
    > include/linux/intel-iommu.h | 10 ++
    > 2 files changed, 180 insertions(+), 22 deletions(-)
    >
    > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
    > index 2c86ac71c774..a61b25ad0d3b 100644
    > --- a/drivers/iommu/intel-iommu.c
    > +++ b/drivers/iommu/intel-iommu.c
    > @@ -2477,6 +2477,7 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu,
    > info->iommu = iommu;
    > info->pasid_table = NULL;
    > info->auxd_enabled = 0;
    > + INIT_LIST_HEAD(&info->auxiliary_domains);
    >
    > if (dev && dev_is_pci(dev)) {
    > struct pci_dev *pdev = to_pci_dev(info->dev);
    > @@ -5010,35 +5011,134 @@ static void intel_iommu_domain_free(struct iommu_domain *domain)
    > domain_exit(to_dmar_domain(domain));
    > }
    >
    > -static int intel_iommu_attach_device(struct iommu_domain *domain,
    > - struct device *dev)
    > +/*
    > + * Check whether a @domain will be attached to the @dev in the
    > + * auxiliary mode.
    > + */
    > +static inline bool
    > +is_device_attach_aux_domain(struct device *dev, struct iommu_domain *domain)
    > {
    > - struct dmar_domain *dmar_domain = to_dmar_domain(domain);
    > - struct intel_iommu *iommu;
    > - int addr_width;
    > - u8 bus, devfn;
    > + struct device_domain_info *info = dev->archdata.iommu;
    >
    > - if (device_is_rmrr_locked(dev)) {
    > - dev_warn(dev, "Device is ineligible for IOMMU domain attach due to platform RMRR requirement. Contact your platform vendor.\n");
    > - return -EPERM;
    > - }
    > + return info && info->auxd_enabled &&
    > + domain->type == IOMMU_DOMAIN_UNMANAGED;
    > +}
    >
    > - /* normally dev is not mapped */
    > - if (unlikely(domain_context_mapped(dev))) {
    > - struct dmar_domain *old_domain;
    > +static void auxiliary_link_device(struct dmar_domain *domain,
    > + struct device *dev)
    > +{
    > + struct device_domain_info *info = dev->archdata.iommu;
    >
    > - old_domain = find_domain(dev);
    > - if (old_domain) {
    > - rcu_read_lock();
    > - dmar_remove_one_dev_info(old_domain, dev);
    > - rcu_read_unlock();
    > + assert_spin_locked(&device_domain_lock);
    > + if (WARN_ON(!info))
    > + return;
    >
    > - if (!domain_type_is_vm_or_si(old_domain) &&
    > - list_empty(&old_domain->devices))
    > - domain_exit(old_domain);
    > + domain->auxd_refcnt++;
    > + list_add(&domain->auxd, &info->auxiliary_domains);
    > +}
    > +
    > +static void auxiliary_unlink_device(struct dmar_domain *domain,
    > + struct device *dev)
    > +{
    > + struct device_domain_info *info = dev->archdata.iommu;
    > +
    > + assert_spin_locked(&device_domain_lock);
    > + if (WARN_ON(!info))
    > + return;
    > +
    > + list_del(&domain->auxd);
    > + domain->auxd_refcnt--;
    > +
    > + if (!domain->auxd_refcnt && domain->default_pasid > 0)
    > + intel_pasid_free_id(domain->default_pasid);
    > +}
    > +
    > +static int domain_add_dev_auxd(struct dmar_domain *domain,
    > + struct device *dev)
    > +{
    > + int ret;
    > + u8 bus, devfn;
    > + unsigned long flags;
    > + struct intel_iommu *iommu;
    > +
    > + iommu = device_to_iommu(dev, &bus, &devfn);
    > + if (!iommu)
    > + return -ENODEV;
    > +
    > + spin_lock_irqsave(&device_domain_lock, flags);
    > + if (domain->default_pasid <= 0) {
    > + domain->default_pasid = intel_pasid_alloc_id(domain, PASID_MIN,
    > + pci_max_pasids(to_pci_dev(dev)), GFP_ATOMIC);
    > + if (domain->default_pasid < 0) {
    > + pr_err("Can't allocate default pasid\n");
    > + ret = -ENODEV;
    > + goto pasid_failed;
    > }
    > }
    >
    > + spin_lock(&iommu->lock);
    You may comment your nested lock policy somewhere.
    > + ret = domain_attach_iommu(domain, iommu);
    > + if (ret)
    > + goto attach_failed;
    > +
    > + /* Setup the PASID entry for mediated devices: */
    > + ret = intel_pasid_setup_second_level(iommu, domain, dev,
    > + domain->default_pasid);
    > + if (ret)
    > + goto table_failed;
    > + spin_unlock(&iommu->lock);
    > +
    > + auxiliary_link_device(domain, dev);
    > +
    > + spin_unlock_irqrestore(&device_domain_lock, flags);
    > +
    > + return 0;
    > +
    > +table_failed:
    > + domain_detach_iommu(domain, iommu);
    > +attach_failed:
    > + spin_unlock(&iommu->lock);
    > + if (!domain->auxd_refcnt && domain->default_pasid > 0)
    > + intel_pasid_free_id(domain->default_pasid);
    > +pasid_failed:
    > + spin_unlock_irqrestore(&device_domain_lock, flags);
    > +
    > + return ret;
    > +}
    > +
    > +static void domain_remove_dev_aux(struct dmar_domain *domain,
    > + struct device *dev)
    > +{
    > + struct device_domain_info *info;
    > + struct intel_iommu *iommu;
    > + unsigned long flags;
    > +
    > + if (!is_device_attach_aux_domain(dev, &domain->domain))
    > + return;
    > +
    > + spin_lock_irqsave(&device_domain_lock, flags);
    > + info = dev->archdata.iommu;
    > + iommu = info->iommu;
    > +
    > + intel_pasid_tear_down_entry(iommu, dev, domain->default_pasid);
    > +
    > + auxiliary_unlink_device(domain, dev);
    > +
    > + spin_lock(&iommu->lock);
    > + domain_detach_iommu(domain, iommu);
    > + spin_unlock(&iommu->lock);
    > +
    > + spin_unlock_irqrestore(&device_domain_lock, flags);
    > +}
    > +
    > +static int __intel_iommu_attach_device(struct iommu_domain *domain,
    > + struct device *dev)
    > +{
    Maybe introducing __intel_iommu_attach_device in a patch prior to that
    one would help the review.
    > + struct dmar_domain *dmar_domain = to_dmar_domain(domain);
    > + struct intel_iommu *iommu;
    > + int addr_width;
    > + u8 bus, devfn;
    > +
    > iommu = device_to_iommu(dev, &bus, &devfn);
    > if (!iommu)
    > return -ENODEV;
    > @@ -5071,7 +5171,47 @@ static int intel_iommu_attach_device(struct iommu_domain *domain,
    > dmar_domain->agaw--;
    > }
    >
    > - return domain_add_dev_info(dmar_domain, dev);
    > + if (is_device_attach_aux_domain(dev, domain))
    > + return domain_add_dev_auxd(dmar_domain, dev);
    why not putting this directly into intel_iommu_attach_device_aux()?
    > + else
    > + return domain_add_dev_info(dmar_domain, dev);
    and this into intel_iommu_attach_device() as
    __intel_iommu_attach_device() is the common part now?
    > +}
    > +
    > +static int intel_iommu_attach_device(struct iommu_domain *domain,
    > + struct device *dev)
    > +{
    > + if (device_is_rmrr_locked(dev)) {
    > + dev_warn(dev, "Device is ineligible for IOMMU domain attach due to platform RMRR requirement. Contact your platform vendor.\n");
    > + return -EPERM;
    > + }
    shouldn't we test this in the common part (ie. in
    __intel_iommu_attach_device). Don't RMRR also impact aux domains ?
    > +
    > + if (is_device_attach_aux_domain(dev, domain))
    > + return -EPERM;
    > +
    > + /* normally dev is not mapped */
    > + if (unlikely(domain_context_mapped(dev))) {
    > + struct dmar_domain *old_domain;
    > +
    > + old_domain = find_domain(dev);
    > + if (old_domain) {
    > + rcu_read_lock();
    > + dmar_remove_one_dev_info(old_domain, dev);
    > + rcu_read_unlock();
    > +
    > + if (!domain_type_is_vm_or_si(old_domain) &&
    > + list_empty(&old_domain->devices))
    > + domain_exit(old_domain);
    > + }
    > + }
    > +
    > + return __intel_iommu_attach_device(domain, dev);
    > +}
    > +
    > +static int intel_iommu_attach_device_aux(struct iommu_domain *domain,
    > + struct device *dev)
    > +{
    > + return is_device_attach_aux_domain(dev, domain) ?
    > + __intel_iommu_attach_device(domain, dev) : -EPERM;
    > }
    >
    > static void intel_iommu_detach_device(struct iommu_domain *domain,
    > @@ -5080,6 +5220,12 @@ static void intel_iommu_detach_device(struct iommu_domain *domain,
    > dmar_remove_one_dev_info(to_dmar_domain(domain), dev);
    > }
    >
    > +static void intel_iommu_detach_device_aux(struct iommu_domain *domain,
    > + struct device *dev)
    > +{
    > + domain_remove_dev_aux(to_dmar_domain(domain), dev);
    > +}
    > +
    > static int intel_iommu_map(struct iommu_domain *domain,
    > unsigned long iova, phys_addr_t hpa,
    > size_t size, int iommu_prot)
    > @@ -5436,6 +5582,8 @@ const struct iommu_ops intel_iommu_ops = {
    > .domain_free = intel_iommu_domain_free,
    > .attach_dev = intel_iommu_attach_device,
    > .detach_dev = intel_iommu_detach_device,
    > + .attach_dev_aux = intel_iommu_attach_device_aux,
    > + .detach_dev_aux = intel_iommu_detach_device_aux,
    > .map = intel_iommu_map,
    > .unmap = intel_iommu_unmap,
    > .iova_to_phys = intel_iommu_iova_to_phys,
    > diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
    > index 6b198e13e75e..678c7fb05e74 100644
    > --- a/include/linux/intel-iommu.h
    > +++ b/include/linux/intel-iommu.h
    > @@ -473,9 +473,11 @@ struct dmar_domain {
    > /* Domain ids per IOMMU. Use u16 since
    > * domain ids are 16 bit wide according
    > * to VT-d spec, section 9.3 */
    > + unsigned int auxd_refcnt; /* Refcount of auxiliary attaching */
    >
    > bool has_iotlb_device;
    > struct list_head devices; /* all devices' list */
    > + struct list_head auxd; /* link to device's auxiliary list */
    > struct iova_domain iovad; /* iova's that belong to this domain */
    >
    > struct dma_pte *pgd; /* virtual address */
    > @@ -494,6 +496,11 @@ struct dmar_domain {
    > 2 == 1GiB, 3 == 512GiB, 4 == 1TiB */
    > u64 max_addr; /* maximum mapped address */
    >
    > + int default_pasid; /*
    > + * The default pasid used for non-SVM
    > + * traffic on mediated devices.
    > + */
    > +
    > struct iommu_domain domain; /* generic domain data structure for
    > iommu core */
    > };
    > @@ -543,6 +550,9 @@ struct device_domain_info {
    > struct list_head link; /* link to domain siblings */
    > struct list_head global; /* link to global list */
    > struct list_head table; /* link to pasid table */
    > + struct list_head auxiliary_domains; /* auxiliary domains
    > + * attached to this device
    > + */
    > u8 bus; /* PCI bus number */
    > u8 devfn; /* PCI devfn number */
    > u16 pfsid; /* SRIOV physical function source ID */
    >
    Thanks

    Eric

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