[PATCH 6.8 298/715] iommu/vt-d: Fix NULL domain on device release

Sasha Levin
2024-03-24T22:39:52Z

From: Lu Baolu <baolu.lu@linux.intel.com>

[ Upstream commit 81e921fd321614c2ad8ac333b041aae1da7a1c6d ]

In the kdump kernel, the IOMMU operates in deferred_attach mode. In this
mode, info->domain may not yet be assigned by the time the release_device
function is called. It leads to the following crash in the crash kernel:

BUG: kernel NULL pointer dereference, address: 000000000000003c
...
RIP: 0010:do_raw_spin_lock+0xa/0xa0
...
_raw_spin_lock_irqsave+0x1b/0x30
intel_iommu_release_device+0x96/0x170
iommu_deinit_device+0x39/0xf0
__iommu_group_remove_device+0xa0/0xd0
iommu_bus_notifier+0x55/0xb0
notifier_call_chain+0x5a/0xd0
blocking_notifier_call_chain+0x41/0x60
bus_notify+0x34/0x50
device_del+0x269/0x3d0
pci_remove_bus_device+0x77/0x100
p2sb_bar+0xae/0x1d0
...
i801_probe+0x423/0x740

Use the release_domain mechanism to fix it. The scalable mode context
entry which is not part of release domain should be cleared in
release_device().

Fixes: 586081d3f6b1 ("iommu/vt-d: Remove DEFER_DEVICE_DOMAIN_INFO")
Reported-by: Eric Badger <ebadger@purestorage.com>
Closes: https://lore.kernel.org/r/20240113181713.1817855-1-ebadger@purestorage.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20240305013305.204605-3-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/iommu/intel/iommu.c | 31 ++++--------------
drivers/iommu/intel/pasid.c | 64 +++++++++++++++++++++++++++++++++++++
drivers/iommu/intel/pasid.h | 1 +
3 files changed, 71 insertions(+), 25 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 31b5d852ba732..5dba58f322f03 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -3874,30 +3874,6 @@ static void domain_context_clear(struct device_domain_info *info)
&domain_context_clear_one_cb, info);
}

-static void dmar_remove_one_dev_info(struct device *dev)
-{
- struct device_domain_info *info = dev_iommu_priv_get(dev);
- struct dmar_domain *domain = info->domain;
- struct intel_iommu *iommu = info->iommu;
- unsigned long flags;
-
- if (!dev_is_real_dma_subdevice(info->dev)) {
- if (dev_is_pci(info->dev) && sm_supported(iommu))
- intel_pasid_tear_down_entry(iommu, info->dev,
- IOMMU_NO_PASID, false);
-
- iommu_disable_pci_caps(info);
- domain_context_clear(info);
- }
-
- spin_lock_irqsave(&domain->lock, flags);
- list_del(&info->link);
- spin_unlock_irqrestore(&domain->lock, flags);
-
- domain_detach_iommu(domain, iommu);
- 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
@@ -4436,7 +4412,11 @@ static void intel_iommu_release_device(struct device *dev)
mutex_lock(&iommu->iopf_lock);
device_rbtree_remove(info);
mutex_unlock(&iommu->iopf_lock);
- dmar_remove_one_dev_info(dev);
+
+ if (sm_supported(iommu) && !dev_is_real_dma_subdevice(dev) &&
+ !context_copied(iommu, info->bus, info->devfn))
+ intel_pasid_teardown_sm_context(dev);
+
intel_pasid_free_table(dev);
intel_iommu_debugfs_remove_dev(info);
kfree(info);
@@ -4942,6 +4922,7 @@ static const struct iommu_dirty_ops intel_dirty_ops = {

const struct iommu_ops intel_iommu_ops = {
.blocked_domain = &blocking_domain,
+ .release_domain = &blocking_domain,
.capable = intel_iommu_capable,
.hw_info = intel_iommu_hw_info,
.domain_alloc = intel_iommu_domain_alloc,
diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
index 746c7abe2237d..a51e895d9a178 100644
--- a/drivers/iommu/intel/pasid.c
+++ b/drivers/iommu/intel/pasid.c
@@ -670,3 +670,67 @@ int intel_pasid_setup_nested(struct intel_iommu *iommu, struct device *dev,

return 0;
}
+
+/*
+ * Interfaces to setup or teardown a pasid table to the scalable-mode
+ * context table entry:
+ */
+
+static void device_pasid_table_teardown(struct device *dev, u8 bus, u8 devfn)
+{
+ struct device_domain_info *info = dev_iommu_priv_get(dev);
+ struct intel_iommu *iommu = info->iommu;
+ struct context_entry *context;
+
+ spin_lock(&iommu->lock);
+ context = iommu_context_addr(iommu, bus, devfn, false);
+ if (!context) {
+ spin_unlock(&iommu->lock);
+ return;
+ }
+
+ context_clear_entry(context);
+ __iommu_flush_cache(iommu, context, sizeof(*context));
+ spin_unlock(&iommu->lock);
+
+ /*
+ * Cache invalidation for changes to a scalable-mode context table
+ * entry.
+ *
+ * Section 6.5.3.3 of the VT-d spec:
+ * - Device-selective context-cache invalidation;
+ * - Domain-selective PASID-cache invalidation to affected domains
+ * (can be skipped if all PASID entries were not-present);
+ * - Domain-selective IOTLB invalidation to affected domains;
+ * - Global Device-TLB invalidation to affected functions.
+ *
+ * The iommu has been parked in the blocking state. All domains have
+ * been detached from the device or PASID. The PASID and IOTLB caches
+ * have been invalidated during the domain detach path.
+ */
+ iommu->flush.flush_context(iommu, 0, PCI_DEVID(bus, devfn),
+ DMA_CCMD_MASK_NOBIT, DMA_CCMD_DEVICE_INVL);
+ devtlb_invalidation_with_pasid(iommu, dev, IOMMU_NO_PASID);
+}
+
+static int pci_pasid_table_teardown(struct pci_dev *pdev, u16 alias, void *data)
+{
+ struct device *dev = data;
+
+ if (dev == &pdev->dev)
+ device_pasid_table_teardown(dev, PCI_BUS_NUM(alias), alias & 0xff);
+
+ return 0;
+}
+
+void intel_pasid_teardown_sm_context(struct device *dev)
+{
+ struct device_domain_info *info = dev_iommu_priv_get(dev);
+
+ if (!dev_is_pci(dev)) {
+ device_pasid_table_teardown(dev, info->bus, info->devfn);
+ return;
+ }
+
+ pci_for_each_dma_alias(to_pci_dev(dev), pci_pasid_table_teardown, dev);
+}
diff --git a/drivers/iommu/intel/pasid.h b/drivers/iommu/intel/pasid.h
index 487ede039bdde..42fda97fd8516 100644
--- a/drivers/iommu/intel/pasid.h
+++ b/drivers/iommu/intel/pasid.h
@@ -318,4 +318,5 @@ void intel_pasid_tear_down_entry(struct intel_iommu *iommu,
bool fault_ignore);
void intel_pasid_setup_page_snoop_control(struct intel_iommu *iommu,
struct device *dev, u32 pasid);
+void intel_pasid_teardown_sm_context(struct device *dev);
#endif /* __INTEL_PASID_H */
--
2.43.0