Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | From | Lu Baolu <> | Subject | [PATCH v2 2/2] iommu/vt-d: Fix NULL domain on device release | Date | Thu, 29 Feb 2024 17:46:13 +0800 |
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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> --- drivers/iommu/intel/pasid.h | 1 + drivers/iommu/intel/iommu.c | 31 +++----------- drivers/iommu/intel/pasid.c | 83 +++++++++++++++++++++++++++++++++++++ 3 files changed, 90 insertions(+), 25 deletions(-)
diff --git a/drivers/iommu/intel/pasid.h b/drivers/iommu/intel/pasid.h index 487ede039bdd..42fda97fd851 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 */ diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index cc3994efd362..f74d42d3258f 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -3869,30 +3869,6 @@ 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 @@ -4431,7 +4407,11 @@ 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); @@ -4922,6 +4902,7 @@ 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 108158e2b907..52068cf52fe2 100644 --- a/drivers/iommu/intel/pasid.c +++ b/drivers/iommu/intel/pasid.c @@ -667,3 +667,86 @@ 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: + */ + +/* + * 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. + * + * Note that RWBF (Required Write-Buffer Flushing) capability has + * been deprecated for scable mode. Section 11.4.2 of the VT-d spec: + * + * HRWBF: Hardware implementations reporting Scalable Mode Translation + * Support (SMTS) as Set also report this field as Clear. + */ +static void sm_context_flush_caches(struct device *dev) +{ + struct device_domain_info *info = dev_iommu_priv_get(dev); + struct intel_iommu *iommu = info->iommu; + + iommu->flush.flush_context(iommu, 0, PCI_DEVID(info->bus, info->devfn), + DMA_CCMD_MASK_NOBIT, DMA_CCMD_DEVICE_INVL); + qi_flush_pasid_cache(iommu, 0, QI_PC_GLOBAL, 0); + iommu->flush.flush_iotlb(iommu, 0, 0, 0, DMA_TLB_GLOBAL_FLUSH); + devtlb_invalidation_with_pasid(iommu, dev, IOMMU_NO_PASID); +} + +static void context_entry_teardown_pasid_table(struct intel_iommu *iommu, + struct context_entry *context) +{ + context_clear_entry(context); + if (!ecap_coherent(iommu->ecap)) + clflush_cache_range(context, sizeof(*context)); +} + +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_entry_teardown_pasid_table(iommu, context); + spin_unlock(&iommu->lock); + + sm_context_flush_caches(dev); +} + +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); +} -- 2.34.1
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