[PATCH v4 5/5] iommu/vt-d: Add is_aux_domain support

From: Lu Baolu
Date: Mon Aug 31 2020 - 23:40:35 EST

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With subdevice information opt-in through iommu_ops.aux_at(de)tach_dev()
interfaces, the vendor iommu driver is able to learn the knowledge about
the relationships between the subdevices and the aux-domains. Implement
is_aux_domain() support based on the relationship knowledges.

Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
---
drivers/iommu/intel/iommu.c | 125 ++++++++++++++++++++++++++----------
include/linux/intel-iommu.h | 17 +++--
2 files changed, 103 insertions(+), 39 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 3c12fd06856c..50431c7b2e71 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -334,6 +334,8 @@ static int intel_iommu_attach_device(struct iommu_domain *domain,
struct device *dev);
static phys_addr_t intel_iommu_iova_to_phys(struct iommu_domain *domain,
dma_addr_t iova);
+static bool intel_iommu_dev_feat_enabled(struct device *dev,
+ enum iommu_dev_features feat);

#ifdef CONFIG_INTEL_IOMMU_DEFAULT_ON
int dmar_disabled = 0;
@@ -1832,6 +1834,7 @@ static struct dmar_domain *alloc_domain(int flags)
domain->flags |= DOMAIN_FLAG_USE_FIRST_LEVEL;
domain->has_iotlb_device = false;
INIT_LIST_HEAD(&domain->devices);
+ INIT_LIST_HEAD(&domain->subdevices);

return domain;
}
@@ -2580,7 +2583,7 @@ 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);
+ INIT_LIST_HEAD(&info->subdevices);

if (dev && dev_is_pci(dev)) {
struct pci_dev *pdev = to_pci_dev(info->dev);
@@ -5137,21 +5140,28 @@ static void intel_iommu_domain_free(struct iommu_domain *domain)
domain_exit(to_dmar_domain(domain));
}

-/*
- * Check whether a @domain could be attached to the @dev through the
- * aux-domain attach/detach APIs.
- */
-static inline bool
-is_aux_domain(struct device *dev, struct iommu_domain *domain)
+/* Lookup subdev_info in the domain's subdevice siblings. */
+static struct subdev_info *
+subdev_lookup_domain(struct dmar_domain *domain, struct device *dev,
+ struct device *subdev)
{
- struct device_domain_info *info = get_domain_info(dev);
+ struct subdev_info *sinfo = NULL, *tmp;

- return info && info->auxd_enabled &&
- domain->type == IOMMU_DOMAIN_UNMANAGED;
+ assert_spin_locked(&device_domain_lock);
+
+ list_for_each_entry(tmp, &domain->subdevices, link_domain) {
+ if ((!dev || tmp->pdev == dev) && tmp->dev == subdev) {
+ sinfo = tmp;
+ break;
+ }
+ }
+
+ return sinfo;
}

-static void auxiliary_link_device(struct dmar_domain *domain,
- struct device *dev)
+static void
+subdev_link_device(struct dmar_domain *domain, struct device *dev,
+ struct subdev_info *sinfo)
{
struct device_domain_info *info = get_domain_info(dev);

@@ -5159,12 +5169,13 @@ static void auxiliary_link_device(struct dmar_domain *domain,
if (WARN_ON(!info))
return;

- domain->auxd_refcnt++;
- list_add(&domain->auxd, &info->auxiliary_domains);
+ list_add(&info->subdevices, &sinfo->link_phys);
+ list_add(&domain->subdevices, &sinfo->link_domain);
}

-static void auxiliary_unlink_device(struct dmar_domain *domain,
- struct device *dev)
+static void
+subdev_unlink_device(struct dmar_domain *domain, struct device *dev,
+ struct subdev_info *sinfo)
{
struct device_domain_info *info = get_domain_info(dev);

@@ -5172,24 +5183,30 @@ static void auxiliary_unlink_device(struct dmar_domain *domain,
if (WARN_ON(!info))
return;

- list_del(&domain->auxd);
- domain->auxd_refcnt--;
+ list_del(&sinfo->link_phys);
+ list_del(&sinfo->link_domain);
+ kfree(sinfo);

- if (!domain->auxd_refcnt && domain->default_pasid > 0)
+ if (list_empty(&domain->subdevices) && domain->default_pasid > 0)
ioasid_free(domain->default_pasid);
}

-static int aux_domain_add_dev(struct dmar_domain *domain,
- struct device *dev)
+static int aux_domain_add_dev(struct dmar_domain *domain, struct device *dev,
+ struct device *subdev)
{
int ret;
unsigned long flags;
struct intel_iommu *iommu;
+ struct subdev_info *sinfo;

iommu = device_to_iommu(dev, NULL, NULL);
if (!iommu)
return -ENODEV;

+ sinfo = kzalloc(sizeof(*sinfo), GFP_KERNEL);
+ if (!sinfo)
+ return -ENOMEM;
+
if (domain->default_pasid <= 0) {
int pasid;

@@ -5199,7 +5216,8 @@ static int aux_domain_add_dev(struct dmar_domain *domain,
NULL);
if (pasid == INVALID_IOASID) {
pr_err("Can't allocate default pasid\n");
- return -ENODEV;
+ ret = -ENODEV;
+ goto pasid_failed;
}
domain->default_pasid = pasid;
}
@@ -5225,7 +5243,10 @@ static int aux_domain_add_dev(struct dmar_domain *domain,
goto table_failed;
spin_unlock(&iommu->lock);

- auxiliary_link_device(domain, dev);
+ sinfo->dev = subdev;
+ sinfo->domain = domain;
+ sinfo->pdev = dev;
+ subdev_link_device(domain, dev, sinfo);

spin_unlock_irqrestore(&device_domain_lock, flags);

@@ -5236,27 +5257,36 @@ static int aux_domain_add_dev(struct dmar_domain *domain,
attach_failed:
spin_unlock(&iommu->lock);
spin_unlock_irqrestore(&device_domain_lock, flags);
- if (!domain->auxd_refcnt && domain->default_pasid > 0)
+ if (list_empty(&domain->subdevices) && domain->default_pasid > 0)
ioasid_free(domain->default_pasid);
+pasid_failed:
+ kfree(sinfo);

return ret;
}

-static void aux_domain_remove_dev(struct dmar_domain *domain,
- struct device *dev)
+static void
+aux_domain_remove_dev(struct dmar_domain *domain, struct device *dev,
+ struct device *subdev)
{
struct device_domain_info *info;
struct intel_iommu *iommu;
+ struct subdev_info *sinfo;
unsigned long flags;

- if (!is_aux_domain(dev, &domain->domain))
+ if (!intel_iommu_dev_feat_enabled(dev, IOMMU_DEV_FEAT_AUX) ||
+ domain->domain.type != IOMMU_DOMAIN_UNMANAGED)
return;

spin_lock_irqsave(&device_domain_lock, flags);
info = get_domain_info(dev);
iommu = info->iommu;
-
- auxiliary_unlink_device(domain, dev);
+ sinfo = subdev_lookup_domain(domain, dev, subdev);
+ if (!sinfo) {
+ spin_unlock_irqrestore(&device_domain_lock, flags);
+ return;
+ }
+ subdev_unlink_device(domain, dev, sinfo);

spin_lock(&iommu->lock);
intel_pasid_tear_down_entry(iommu, dev, domain->default_pasid, false);
@@ -5319,7 +5349,8 @@ static int intel_iommu_attach_device(struct iommu_domain *domain,
return -EPERM;
}

- if (is_aux_domain(dev, domain))
+ if (intel_iommu_dev_feat_enabled(dev, IOMMU_DEV_FEAT_AUX) &&
+ domain->type == IOMMU_DOMAIN_UNMANAGED)
return -EPERM;

/* normally dev is not mapped */
@@ -5344,14 +5375,15 @@ intel_iommu_aux_attach_device(struct iommu_domain *domain,
{
int ret;

- if (!is_aux_domain(dev, domain))
+ if (!intel_iommu_dev_feat_enabled(dev, IOMMU_DEV_FEAT_AUX) ||
+ domain->type != IOMMU_DOMAIN_UNMANAGED)
return -EPERM;

ret = prepare_domain_attach_device(domain, dev);
if (ret)
return ret;

- return aux_domain_add_dev(to_dmar_domain(domain), dev);
+ return aux_domain_add_dev(to_dmar_domain(domain), dev, subdev);
}

static void intel_iommu_detach_device(struct iommu_domain *domain,
@@ -5364,7 +5396,7 @@ static void
intel_iommu_aux_detach_device(struct iommu_domain *domain, struct device *dev,
struct device *subdev)
{
- aux_domain_remove_dev(to_dmar_domain(domain), dev);
+ aux_domain_remove_dev(to_dmar_domain(domain), dev, subdev);
}

/*
@@ -6020,6 +6052,32 @@ static bool intel_iommu_is_attach_deferred(struct iommu_domain *domain,
return attach_deferred(dev);
}

+static int
+intel_iommu_domain_get_attr(struct iommu_domain *domain,
+ enum iommu_attr attr, void *data)
+{
+ struct dmar_domain *dmar_domain = to_dmar_domain(domain);
+ unsigned long flags;
+ int ret;
+
+ if (domain->type != IOMMU_DOMAIN_UNMANAGED)
+ return -EINVAL;
+
+ switch (attr) {
+ case DOMAIN_ATTR_IS_AUX:
+ spin_lock_irqsave(&device_domain_lock, flags);
+ ret = !IS_ERR_OR_NULL(subdev_lookup_domain(dmar_domain,
+ NULL, data));
+ spin_unlock_irqrestore(&device_domain_lock, flags);
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ return ret;
+}
+
static int
intel_iommu_domain_set_attr(struct iommu_domain *domain,
enum iommu_attr attr, void *data)
@@ -6073,6 +6131,7 @@ const struct iommu_ops intel_iommu_ops = {
.domain_alloc = intel_iommu_domain_alloc,
.domain_free = intel_iommu_domain_free,
.domain_set_attr = intel_iommu_domain_set_attr,
+ .domain_get_attr = intel_iommu_domain_get_attr,
.attach_dev = intel_iommu_attach_device,
.detach_dev = intel_iommu_detach_device,
.aux_attach_dev = intel_iommu_aux_attach_device,
diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index b1ed2f25f7c0..47ba1904c691 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -526,11 +526,9 @@ 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 list_head subdevices; /* all subdevices' list */
struct iova_domain iovad; /* iova's that belong to this domain */

struct dma_pte *pgd; /* virtual address */
@@ -603,14 +601,21 @@ struct intel_iommu {
struct dmar_drhd_unit *drhd;
};

+/* Per subdevice private data */
+struct subdev_info {
+ struct list_head link_phys; /* link to phys device siblings */
+ struct list_head link_domain; /* link to domain siblings */
+ struct device *pdev; /* physical device derived from */
+ struct device *dev; /* subdevice node */
+ struct dmar_domain *domain; /* aux-domain */
+};
+
/* PCI domain-device relationship */
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
- */
+ struct list_head subdevices; /* subdevices sibling */
u32 segment; /* PCI segment number */
u8 bus; /* PCI bus number */
u8 devfn; /* PCI devfn number */
--
2.17.1

Next message: Bjorn Andersson: "Re: [PATCH 03/19] iommu/arm-smmu: Add support for split pagetables"
Previous message: Lu Baolu: "[PATCH v4 4/5] vfio/type1: Use iommu_aux_at(de)tach_group() APIs"
In reply to: Lu Baolu: "[PATCH v4 4/5] vfio/type1: Use iommu_aux_at(de)tach_group() APIs"
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