[PATCH v3 2/7] iommu/vt-d: Add device_block_translation() helper

Lu Baolu
2022-11-14T01:48:11Z

If domain attaching to device fails, the IOMMU driver should bring the
device to blocking DMA state. The upper layer is expected to recover it
by attaching a new domain. Use device_block_translation() in the error
path of dev_attach to make the behavior specific.

The difference between device_block_translation() and the previous
dmar_remove_one_dev_info() is that, in the scalable mode, it is the
RID2PASID entry instead of context entry being cleared. As a result,
enabling PCI capabilities is moved up.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
drivers/iommu/intel/iommu.c | 44 ++++++++++++++++++++++++++++++++-----
1 file changed, 38 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index bc42a2c84e2a..16eeff2f7e19 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -277,7 +277,7 @@ static LIST_HEAD(dmar_satc_units);
#define for_each_rmrr_units(rmrr) \
list_for_each_entry(rmrr, &dmar_rmrr_units, list)

-static void dmar_remove_one_dev_info(struct device *dev);
+static void device_block_translation(struct device *dev);

int dmar_disabled = !IS_ENABLED(CONFIG_INTEL_IOMMU_DEFAULT_ON);
int intel_iommu_sm = IS_ENABLED(CONFIG_INTEL_IOMMU_SCALABLE_MODE_DEFAULT_ON);
@@ -1402,7 +1402,7 @@ static void iommu_enable_pci_caps(struct device_domain_info *info)
{
struct pci_dev *pdev;

- if (!info || !dev_is_pci(info->dev))
+ if (!dev_is_pci(info->dev))
return;

pdev = to_pci_dev(info->dev);
@@ -2047,7 +2047,6 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
} else {
iommu_flush_write_buffer(iommu);
}
- iommu_enable_pci_caps(info);

ret = 0;

@@ -2489,7 +2488,7 @@ static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev)
dev, PASID_RID2PASID);
if (ret) {
dev_err(dev, "Setup RID2PASID failed\n");
- dmar_remove_one_dev_info(dev);
+ device_block_translation(dev);
return ret;
}
}
@@ -2497,10 +2496,12 @@ static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev)
ret = domain_context_mapping(domain, dev);
if (ret) {
dev_err(dev, "Domain context map failed\n");
- dmar_remove_one_dev_info(dev);
+ device_block_translation(dev);
return ret;
}

+ iommu_enable_pci_caps(info);
+
return 0;
}

@@ -4111,6 +4112,37 @@ static void dmar_remove_one_dev_info(struct device *dev)
info->domain = NULL;
}

+/*
+ * Clear the page table pointer in context or pasid table entries so that
+ * all DMA requests without PASID from the device are blocked. If the page
+ * table has been set, clean up the data structures.
+ */
+static void device_block_translation(struct device *dev)
+{
+ struct device_domain_info *info = dev_iommu_priv_get(dev);
+ struct intel_iommu *iommu = info->iommu;
+ unsigned long flags;
+
+ iommu_disable_dev_iotlb(info);
+ if (!dev_is_real_dma_subdevice(dev)) {
+ if (sm_supported(iommu))
+ intel_pasid_tear_down_entry(iommu, dev,
+ PASID_RID2PASID, false);
+ else
+ domain_context_clear(info);
+ }
+
+ if (!info->domain)
+ return;
+
+ spin_lock_irqsave(&info->domain->lock, flags);
+ list_del(&info->link);
+ spin_unlock_irqrestore(&info->domain->lock, flags);
+
+ domain_detach_iommu(info->domain, iommu);
+ info->domain = NULL;
+}
+
static int md_domain_init(struct dmar_domain *domain, int guest_width)
{
int adjust_width;
@@ -4232,7 +4264,7 @@ static int intel_iommu_attach_device(struct iommu_domain *domain,
struct device_domain_info *info = dev_iommu_priv_get(dev);

if (info->domain)
- dmar_remove_one_dev_info(dev);
+ device_block_translation(dev);
}

ret = prepare_domain_attach_device(domain, dev);
--
2.34.1