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iommu/vt-d: Fix RID2PASID setup/teardown failure

The IOMMU driver shares the pasid table for PCI alias devices. When the RID2PASID entry of the shared pasid table has been filled by the first device, the subsequent device will encounter the "DMAR: Setup RID2PASID failed" failure as the pasid entry has already been marked as present. As the result, the IOMMU probing process will be aborted. On the contrary, when any alias device is hot-removed from the system, for example, by writing to /sys/bus/pci/devices/.../remove, the shared RID2PASID will be cleared without any notifications to other devices. As the result, any DMAs from those rest devices are blocked. Sharing pasid table among PCI alias devices could save two memory pages for devices underneath the PCIe-to-PCI bridges. Anyway, considering that those devices are rare on modern platforms that support VT-d in scalable mode and the saved memory is negligible, it's reasonable to remove this part of immature code to make the driver feasible and stable.

Lu Baolu committed 4 years ago

Commit 4140d771 parent 316f92a4 files · +3 −94Browse files

Unified · Split

4 files
  1. drivers/iommu/intel/iommu.c +0 −24
  2. drivers/iommu/intel/pasid.c +3 −66
  3. drivers/iommu/intel/pasid.h +0 −1
  4. include/linux/intel-iommu.h +0 −3
drivers/iommu/intel/iommu.c+0−24
@@ -320,30 +320,6 @@ EXPORT_SYMBOL_GPL(intel_iommu_gfx_mapped); · 319 unmodified lines
320320 DEFINE_SPINLOCK(device_domain_lock);
321321 static LIST_HEAD(device_domain_list);
322322
323−/*
324− * Iterate over elements in device_domain_list and call the specified
325− * callback @fn against each element.
326− */
327−int for_each_device_domain(int (*fn)(struct device_domain_info *info,
328− void *data), void *data)
329−{
330− int ret = 0;
331− unsigned long flags;
332− struct device_domain_info *info;
333−
334− spin_lock_irqsave(&device_domain_lock, flags);
335− list_for_each_entry(info, &device_domain_list, global) {
336− ret = fn(info, data);
337− if (ret) {
338− spin_unlock_irqrestore(&device_domain_lock, flags);
339− return ret;
340− }
341− }
342− spin_unlock_irqrestore(&device_domain_lock, flags);
343−
344− return 0;
345−}
346−
347323 const struct iommu_ops intel_iommu_ops;
348324
349325 static bool translation_pre_enabled(struct intel_iommu *iommu)
drivers/iommu/intel/pasid.c+3−66
@@ -86,54 +86,6 @@ void vcmd_free_pasid(struct intel_iommu *iommu, u32 pasid) · 85 unmodified lines
8686 /*
8787 * Per device pasid table management:
8888 */
89−static inline void
90−device_attach_pasid_table(struct device_domain_info *info,
91− struct pasid_table *pasid_table)
92−{
93− info->pasid_table = pasid_table;
94− list_add(&info->table, &pasid_table->dev);
95−}
96−
97−static inline void
98−device_detach_pasid_table(struct device_domain_info *info,
99− struct pasid_table *pasid_table)
100−{
101− info->pasid_table = NULL;
102− list_del(&info->table);
103−}
104−
105−struct pasid_table_opaque {
106− struct pasid_table **pasid_table;
107− int segment;
108− int bus;
109− int devfn;
110−};
111−
112−static int search_pasid_table(struct device_domain_info *info, void *opaque)
113−{
114− struct pasid_table_opaque *data = opaque;
115−
116− if (info->iommu->segment == data->segment &&
117− info->bus == data->bus &&
118− info->devfn == data->devfn &&
119− info->pasid_table) {
120− *data->pasid_table = info->pasid_table;
121− return 1;
122− }
123−
124− return 0;
125−}
126−
127−static int get_alias_pasid_table(struct pci_dev *pdev, u16 alias, void *opaque)
128−{
129− struct pasid_table_opaque *data = opaque;
130−
131− data->segment = pci_domain_nr(pdev->bus);
132− data->bus = PCI_BUS_NUM(alias);
133− data->devfn = alias & 0xff;
134−
135− return for_each_device_domain(&search_pasid_table, data);
136−}
13789
13890 /*
13991 * Allocate a pasid table for @dev. It should be called in a
@@ -143,28 +95,18 @@ int intel_pasid_alloc_table(struct device *dev) · 3 unmodified lines
14395 {
14496 struct device_domain_info *info;
14597 struct pasid_table *pasid_table;
146− struct pasid_table_opaque data;
14798 struct page *pages;
14899 u32 max_pasid = 0;
149− int ret, order;
150− int size;
100+ int order, size;
151101
152102 might_sleep();
153103 info = dev_iommu_priv_get(dev);
154104 if (WARN_ON(!info || !dev_is_pci(dev) || info->pasid_table))
155105 return -EINVAL;
156106
157− /* DMA alias device already has a pasid table, use it: */
158− data.pasid_table = &pasid_table;
159− ret = pci_for_each_dma_alias(to_pci_dev(dev),
160− &get_alias_pasid_table, &data);
161− if (ret)
162− goto attach_out;
163−
164107 pasid_table = kzalloc(sizeof(*pasid_table), GFP_KERNEL);
165108 if (!pasid_table)
166109 return -ENOMEM;
167− INIT_LIST_HEAD(&pasid_table->dev);
168110
169111 if (info->pasid_supported)
170112 max_pasid = min_t(u32, pci_max_pasids(to_pci_dev(dev)),
@@ -182,9 +124,7 @@ int intel_pasid_alloc_table(struct device *dev) · 11 unmodified lines
182124 pasid_table->table = page_address(pages);
183125 pasid_table->order = order;
184126 pasid_table->max_pasid = 1 << (order + PAGE_SHIFT + 3);
185−
186−attach_out:
187− device_attach_pasid_table(info, pasid_table);
127+ info->pasid_table = pasid_table;
188128
189129 return 0;
190130 }
@@ -202,10 +142,7 @@ void intel_pasid_free_table(struct device *dev) · 11 unmodified lines
202142 return;
203143
204144 pasid_table = info->pasid_table;
205− device_detach_pasid_table(info, pasid_table);
206−
207− if (!list_empty(&pasid_table->dev))
208− return;
145+ info->pasid_table = NULL;
209146
210147 /* Free scalable mode PASID directory tables: */
211148 dir = pasid_table->table;
drivers/iommu/intel/pasid.h+0−1
@@ -74,7 +74,6 @@ struct pasid_table { · 73 unmodified lines
7474 void *table; /* pasid table pointer */
7575 int order; /* page order of pasid table */
7676 u32 max_pasid; /* max pasid */
77− struct list_head dev; /* device list */
7877 };
7978
8079 /* Get PRESENT bit of a PASID directory entry. */
include/linux/intel-iommu.h+0−3
@@ -612,7 +612,6 @@ struct intel_iommu { · 611 unmodified lines
612612 struct device_domain_info {
613613 struct list_head link; /* link to domain siblings */
614614 struct list_head global; /* link to global list */
615− struct list_head table; /* link to pasid table */
616615 u32 segment; /* PCI segment number */
617616 u8 bus; /* PCI bus number */
618617 u8 devfn; /* PCI devfn number */
@@ -729,8 +728,6 @@ extern int dmar_ir_support(void); · 110 unmodified lines
729728 void *alloc_pgtable_page(int node);
730729 void free_pgtable_page(void *vaddr);
731730 struct intel_iommu *domain_get_iommu(struct dmar_domain *domain);
732−int for_each_device_domain(int (*fn)(struct device_domain_info *info,
733− void *data), void *data);
734731 void iommu_flush_write_buffer(struct intel_iommu *iommu);
735732 int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct device *dev);
736733 struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devfn);