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LuBaolujoergroedel
LuBaolu
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joergroedel
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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. Fixes: ef848b7 ("iommu/vt-d: Setup pasid entry for RID2PASID support") Reported-by: Chenyi Qiang <chenyi.qiang@intel.com> Reported-by: Ethan Zhao <haifeng.zhao@linux.intel.com> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Reviewed-by: Ethan Zhao <haifeng.zhao@linux.intel.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20220623065720.727849-1-baolu.lu@linux.intel.com Link: https://lore.kernel.org/r/20220625133430.2200315-2-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
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4 files changed

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‎drivers/iommu/intel/iommu.c

Lines changed: 0 additions & 24 deletions
Original file line numberDiff line numberDiff line change
@@ -320,30 +320,6 @@ EXPORT_SYMBOL_GPL(intel_iommu_gfx_mapped);
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

Lines changed: 3 additions & 66 deletions
Original file line numberDiff line numberDiff line change
@@ -86,54 +86,6 @@ void vcmd_free_pasid(struct intel_iommu *iommu, u32 pasid)
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)
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)
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)
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

Lines changed: 0 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -74,7 +74,6 @@ struct pasid_table {
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

Lines changed: 0 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -612,7 +612,6 @@ struct intel_iommu {
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);
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);

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