Re: [PATCH v4 5/7] iommu/vt-d: Make device pasid attachment explicit

From: Baolu Lu
Date: Sun Apr 09 2023 - 22:46:06 EST

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On 4/8/23 2:05 AM, Jacob Pan wrote:

@@ -2429,10 +2475,11 @@ static int __init si_domain_init(int hw)
return 0;
}
-static int dmar_domain_attach_device(struct dmar_domain *domain,
- struct device *dev)
+static int dmar_domain_attach_device_pasid(struct dmar_domain *domain,
+ struct device *dev, ioasid_t pasid)
{
struct device_domain_info *info = dev_iommu_priv_get(dev);
+ struct device_pasid_info *dev_pasid;
struct intel_iommu *iommu;
unsigned long flags;
u8 bus, devfn;
@@ -2442,43 +2489,57 @@ static int dmar_domain_attach_device(struct dmar_domain *domain,
if (!iommu)
return -ENODEV;
+ dev_pasid = kzalloc(sizeof(*dev_pasid), GFP_KERNEL);
+ if (!dev_pasid)
+ return -ENOMEM;
+
ret = domain_attach_iommu(domain, iommu);
if (ret)
- return ret;
+ goto exit_free;
+
info->domain = domain;
+ dev_pasid->pasid = pasid;
+ dev_pasid->dev = dev;
spin_lock_irqsave(&domain->lock, flags);
- list_add(&info->link, &domain->devices);
+ if (!info->dev_attached)
+ list_add(&info->link, &domain->devices);
+
+ list_add(&dev_pasid->link_domain, &domain->dev_pasids);
spin_unlock_irqrestore(&domain->lock, flags);
/* PASID table is mandatory for a PCI device in scalable mode. */
if (sm_supported(iommu) && !dev_is_real_dma_subdevice(dev)) {
/* Setup the PASID entry for requests without PASID: */
if (hw_pass_through && domain_type_is_si(domain))
- ret = intel_pasid_setup_pass_through(iommu, domain,
- dev, PASID_RID2PASID);
+ ret = intel_pasid_setup_pass_through(iommu, domain, dev, pasid);
else if (domain->use_first_level)
- ret = domain_setup_first_level(iommu, domain, dev,
- PASID_RID2PASID);
+ ret = domain_setup_first_level(iommu, domain, dev, pasid);
else
- ret = intel_pasid_setup_second_level(iommu, domain,
- dev, PASID_RID2PASID);
+ ret = intel_pasid_setup_second_level(iommu, domain, dev, pasid);
if (ret) {
- dev_err(dev, "Setup RID2PASID failed\n");
+ dev_err(dev, "Setup PASID %d failed\n", pasid);
device_block_translation(dev);
- return ret;
+ goto exit_free;
}
}
+ /* device context already activated, we are done */
+ if (info->dev_attached)
+ goto exit;
ret = domain_context_mapping(domain, dev);
if (ret) {
dev_err(dev, "Domain context map failed\n");
device_block_translation(dev);
- return ret;
+ goto exit_free;
}
iommu_enable_pci_caps(info);
-
+ info->dev_attached = 1;
+exit:
return 0;
+exit_free:
+ kfree(dev_pasid);
+ return ret;
}
static bool device_has_rmrr(struct device *dev)
@@ -4029,8 +4090,7 @@ static void device_block_translation(struct device *dev)
iommu_disable_pci_caps(info);
if (!dev_is_real_dma_subdevice(dev)) {
if (sm_supported(iommu))
- intel_pasid_tear_down_entry(iommu, dev,
- PASID_RID2PASID, false);
+ intel_iommu_detach_device_pasid(&info->domain->domain, dev, PASID_RID2PASID);
else
domain_context_clear(info);
}
@@ -4040,6 +4100,7 @@ static void device_block_translation(struct device *dev)
spin_lock_irqsave(&info->domain->lock, flags);
list_del(&info->link);
+ info->dev_attached = 0;
spin_unlock_irqrestore(&info->domain->lock, flags);
domain_detach_iommu(info->domain, iommu);
@@ -4186,7 +4247,7 @@ static int intel_iommu_attach_device(struct iommu_domain *domain,
if (ret)
return ret;
- return dmar_domain_attach_device(to_dmar_domain(domain), dev);
+ return dmar_domain_attach_device_pasid(to_dmar_domain(domain), dev, PASID_RID2PASID);
}

For VT-d driver, attach_dev and attach_dev_pasid have different
meanings. Merging them into one helper may lead to confusion. What do
you think of the following code? The dmar_domain_attach_device_pasid()
helper could be reused for attach_dev_pasid path.

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 7c2f4bd33582..09ae62bc3724 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -2434,6 +2434,40 @@ static int __init si_domain_init(int hw)
return 0;
}

+
+static int dmar_domain_attach_device_pasid(struct dmar_domain *domain,
+ struct intel_iommu *iommu,
+ struct device *dev, ioasid_t pasid)
+{
+ struct device_pasid_info *dev_pasid;
+ unsigned long flags;
+ int ret;
+
+ dev_pasid = kzalloc(sizeof(*dev_pasid), GFP_KERNEL);
+ if (!dev_pasid)
+ return -ENOMEM;
+
+ if (hw_pass_through && domain_type_is_si(domain))
+ ret = intel_pasid_setup_pass_through(iommu, domain, dev, pasid);
+ else if (domain->use_first_level)
+ ret = domain_setup_first_level(iommu, domain, dev, pasid);
+ else
+ ret = intel_pasid_setup_second_level(iommu, domain, dev, pasid);
+
+ if (ret) {
+ kfree(dev_pasid);
+ return ret;
+ }
+
+ dev_pasid->pasid = pasid;
+ dev_pasid->dev = dev;
+ spin_lock_irqsave(&domain->lock, flags);
+ list_add(&dev_pasid->link_domain, &domain->dev_pasids);
+ spin_unlock_irqrestore(&domain->lock, flags);
+
+ return 0;
+}
+
static int dmar_domain_attach_device(struct dmar_domain *domain,
struct device *dev)
{
@@ -2458,15 +2492,8 @@ static int dmar_domain_attach_device(struct dmar_domain *domain,
/* PASID table is mandatory for a PCI device in scalable mode. */
if (sm_supported(iommu) && !dev_is_real_dma_subdevice(dev)) {
/* Setup the PASID entry for requests without PASID: */
- if (hw_pass_through && domain_type_is_si(domain))
- ret = intel_pasid_setup_pass_through(iommu, domain,
- dev, PASID_RID2PASID);
- else if (domain->use_first_level)
- ret = domain_setup_first_level(iommu, domain, dev,
- PASID_RID2PASID);
- else
- ret = intel_pasid_setup_second_level(iommu, domain,
- dev, PASID_RID2PASID);
+ ret = dmar_domain_attach_device_pasid(domain, iommu, dev,
+ PASID_RID2PASID);
if (ret) {
dev_err(dev, "Setup RID2PASID failed\n");
device_block_translation(dev);

static int intel_iommu_map(struct iommu_domain *domain,
@@ -4675,26 +4736,52 @@ static void intel_iommu_iotlb_sync_map(struct iommu_domain *domain,
__mapping_notify_one(info->iommu, dmar_domain, pfn, pages);
}
-static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid)
+static void intel_iommu_detach_device_pasid(struct iommu_domain *domain,
+ struct device *dev, ioasid_t pasid)
{
- struct intel_iommu *iommu = device_to_iommu(dev, NULL, NULL);
- struct iommu_domain *domain;
+ struct device_domain_info *info = dev_iommu_priv_get(dev);
+ struct dmar_domain *dmar_domain = to_dmar_domain(domain);
+ struct device_pasid_info *i, *dev_pasid = NULL;
+ struct intel_iommu *iommu = info->iommu;
+ unsigned long flags;
- /* Domain type specific cleanup: */
- domain = iommu_get_domain_for_dev_pasid(dev, pasid, 0);
- if (domain) {
- switch (domain->type) {
- case IOMMU_DOMAIN_SVA:
- intel_svm_remove_dev_pasid(dev, pasid);
- break;
- default:
- /* should never reach here */
- WARN_ON(1);
+ spin_lock_irqsave(&dmar_domain->lock, flags);
+ list_for_each_entry(i, &dmar_domain->dev_pasids, link_domain) {
+ if (i->dev == dev && i->pasid == pasid) {
+ list_del(&i->link_domain);
+ dev_pasid = i;
break;
}
}
+ spin_unlock_irqrestore(&dmar_domain->lock, flags);
+ if (WARN_ON(!dev_pasid))
+ return;
+
+ /* PASID entry already cleared during SVA unbind */
+ if (domain->type != IOMMU_DOMAIN_SVA)
+ intel_pasid_tear_down_entry(iommu, dev, pasid, false);
+
+ kfree(dev_pasid);
+}
+
+static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid)
+{
+ struct device_domain_info *info = dev_iommu_priv_get(dev);
+ struct dmar_domain *dmar_domain;
+ struct iommu_domain *domain;
+
+ domain = iommu_get_domain_for_dev_pasid(dev, pasid, 0);
+ dmar_domain = to_dmar_domain(domain);
+
+ /*
+ * SVA Domain type specific cleanup: Not ideal but not until we have
+ * IOPF capable domain specific ops, we need this special case.
+ */
+ if (domain->type == IOMMU_DOMAIN_SVA)
+ return intel_svm_remove_dev_pasid(dev, pasid);
- intel_pasid_tear_down_entry(iommu, dev, pasid, false);
+ intel_iommu_detach_device_pasid(domain, dev, pasid);
+ domain_detach_iommu(dmar_domain, info->iommu);
}

The remove_dev_pasid path need to change only after attach_dev_pasid op
is added, right? If so, we should move such change into the next patch.

const struct iommu_ops intel_iommu_ops = {
diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
index 65b15be72878..b6c26f25d1ba 100644
--- a/drivers/iommu/intel/iommu.h
+++ b/drivers/iommu/intel/iommu.h
@@ -595,6 +595,7 @@ struct dmar_domain {
spinlock_t lock; /* Protect device tracking lists */
struct list_head devices; /* all devices' list */
+ struct list_head dev_pasids; /* all attached pasids */
struct dma_pte *pgd; /* virtual address */
int gaw; /* max guest address width */
@@ -708,6 +709,7 @@ struct device_domain_info {
u8 ats_supported:1;
u8 ats_enabled:1;
u8 dtlb_extra_inval:1; /* Quirk for devices need extra flush */
+ u8 dev_attached:1; /* Device context activated */
u8 ats_qdep;
struct device *dev; /* it's NULL for PCIe-to-PCI bridge */
struct intel_iommu *iommu; /* IOMMU used by this device */
@@ -715,6 +717,12 @@ struct device_domain_info {
struct pasid_table *pasid_table; /* pasid table */
};
+struct device_pasid_info {
+ struct list_head link_domain; /* link to domain siblings */
+ struct device *dev; /* physical device derived from */
+ ioasid_t pasid; /* PASID on physical device */
+};
+
static inline void __iommu_flush_cache(
struct intel_iommu *iommu, void *addr, int size)
{

Best regards,
baolu

Next message: Gang Li: "[PATCH v3] mm: oom: introduce cpuset oom"
Previous message: Yue Hu: "Re: [PATCH 3/7] erofs: move packed inode out of the compression part"
Next in thread: Baolu Lu: "Re: [PATCH v4 5/7] iommu/vt-d: Make device pasid attachment explicit"
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