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

Baolu Lu
2023-04-10T02:46:05Z

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