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Subject[PATCH v4 02/12] iommu/vt-d: Manage scalalble mode PASID tables
Date
In scalable mode, pasid structure is a two level table with
a pasid directory table and a pasid table. Any pasid entry
can be identified by a pasid value in below way.

1
9 6 5 0
.-----------------------.-------.
| PASID | |
'-----------------------'-------' .-------------.
| | | |
| | | |
| | | |
| .-----------. | .-------------.
| | | |----->| PASID Entry |
| | | | '-------------'
| | | |Plus | |
| .-----------. | | |
|---->| DIR Entry |-------->| |
| '-----------' '-------------'
.---------. |Plus | |
| Context | | | |
| Entry |------->| |
'---------' '-----------'

This changes the pasid table APIs to support scalable mode
PASID directory and PASID table. It also adds a helper to
get the PASID table entry according to the pasid value.

Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Sanjay Kumar <sanjay.k.kumar@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
---
drivers/iommu/intel-iommu.c | 9 ++--
drivers/iommu/intel-pasid.c | 84 ++++++++++++++++++++++++++++++-------
drivers/iommu/intel-pasid.h | 12 +++++-
drivers/iommu/intel-svm.c | 6 +--
4 files changed, 86 insertions(+), 25 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 149561420a75..9c8fabe42b04 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -2482,12 +2482,13 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu,
if (dev)
dev->archdata.iommu = info;

- if (dev && dev_is_pci(dev) && info->pasid_supported) {
+ /* PASID table is mandatory for a PCI device in scalable mode. */
+ if (dev && dev_is_pci(dev) && sm_supported(iommu)) {
ret = intel_pasid_alloc_table(dev);
if (ret) {
- pr_warn("No pasid table for %s, pasid disabled\n",
- dev_name(dev));
- info->pasid_supported = 0;
+ __dmar_remove_one_dev_info(info);
+ spin_unlock_irqrestore(&device_domain_lock, flags);
+ return NULL;
}
}
spin_unlock_irqrestore(&device_domain_lock, flags);
diff --git a/drivers/iommu/intel-pasid.c b/drivers/iommu/intel-pasid.c
index fe95c9bd4d33..aeae209ec1b7 100644
--- a/drivers/iommu/intel-pasid.c
+++ b/drivers/iommu/intel-pasid.c
@@ -123,12 +123,12 @@ int intel_pasid_alloc_table(struct device *dev)
struct pasid_table *pasid_table;
struct pasid_table_opaque data;
struct page *pages;
- size_t size, count;
+ int max_pasid = 0;
int ret, order;
+ int size;

info = dev->archdata.iommu;
- if (WARN_ON(!info || !dev_is_pci(dev) ||
- !info->pasid_supported || info->pasid_table))
+ if (WARN_ON(!info || !dev_is_pci(dev) || info->pasid_table))
return -EINVAL;

/* DMA alias device already has a pasid table, use it: */
@@ -143,18 +143,20 @@ int intel_pasid_alloc_table(struct device *dev)
return -ENOMEM;
INIT_LIST_HEAD(&pasid_table->dev);

- size = sizeof(struct pasid_entry);
- count = min_t(int, pci_max_pasids(to_pci_dev(dev)), intel_pasid_max_id);
- order = get_order(size * count);
+ if (info->pasid_supported)
+ max_pasid = min_t(int, pci_max_pasids(to_pci_dev(dev)),
+ intel_pasid_max_id);
+
+ size = max_pasid >> (PASID_PDE_SHIFT - 3);
+ order = size ? get_order(size) : 0;
pages = alloc_pages_node(info->iommu->node,
- GFP_ATOMIC | __GFP_ZERO,
- order);
+ GFP_ATOMIC | __GFP_ZERO, order);
if (!pages)
return -ENOMEM;

pasid_table->table = page_address(pages);
pasid_table->order = order;
- pasid_table->max_pasid = count;
+ pasid_table->max_pasid = 1 << (order + PAGE_SHIFT + 3);

attach_out:
device_attach_pasid_table(info, pasid_table);
@@ -162,14 +164,33 @@ int intel_pasid_alloc_table(struct device *dev)
return 0;
}

+/* Get PRESENT bit of a PASID directory entry. */
+static inline bool
+pasid_pde_is_present(struct pasid_dir_entry *pde)
+{
+ return READ_ONCE(pde->val) & PASID_PTE_PRESENT;
+}
+
+/* Get PASID table from a PASID directory entry. */
+static inline struct pasid_entry *
+get_pasid_table_from_pde(struct pasid_dir_entry *pde)
+{
+ if (!pasid_pde_is_present(pde))
+ return NULL;
+
+ return phys_to_virt(READ_ONCE(pde->val) & PDE_PFN_MASK);
+}
+
void intel_pasid_free_table(struct device *dev)
{
struct device_domain_info *info;
struct pasid_table *pasid_table;
+ struct pasid_dir_entry *dir;
+ struct pasid_entry *table;
+ int i, max_pde;

info = dev->archdata.iommu;
- if (!info || !dev_is_pci(dev) ||
- !info->pasid_supported || !info->pasid_table)
+ if (!info || !dev_is_pci(dev) || !info->pasid_table)
return;

pasid_table = info->pasid_table;
@@ -178,6 +199,14 @@ void intel_pasid_free_table(struct device *dev)
if (!list_empty(&pasid_table->dev))
return;

+ /* Free scalable mode PASID directory tables: */
+ dir = pasid_table->table;
+ max_pde = pasid_table->max_pasid >> PASID_PDE_SHIFT;
+ for (i = 0; i < max_pde; i++) {
+ table = get_pasid_table_from_pde(&dir[i]);
+ free_pgtable_page(table);
+ }
+
free_pages((unsigned long)pasid_table->table, pasid_table->order);
kfree(pasid_table);
}
@@ -206,17 +235,37 @@ int intel_pasid_get_dev_max_id(struct device *dev)

struct pasid_entry *intel_pasid_get_entry(struct device *dev, int pasid)
{
+ struct device_domain_info *info;
struct pasid_table *pasid_table;
+ struct pasid_dir_entry *dir;
struct pasid_entry *entries;
+ int dir_index, index;

pasid_table = intel_pasid_get_table(dev);
if (WARN_ON(!pasid_table || pasid < 0 ||
pasid >= intel_pasid_get_dev_max_id(dev)))
return NULL;

- entries = pasid_table->table;
+ dir = pasid_table->table;
+ info = dev->archdata.iommu;
+ dir_index = pasid >> PASID_PDE_SHIFT;
+ index = pasid & PASID_PTE_MASK;
+
+ spin_lock(&pasid_lock);
+ entries = get_pasid_table_from_pde(&dir[dir_index]);
+ if (!entries) {
+ entries = alloc_pgtable_page(info->iommu->node);
+ if (!entries) {
+ spin_unlock(&pasid_lock);
+ return NULL;
+ }
+
+ WRITE_ONCE(dir[dir_index].val,
+ (u64)virt_to_phys(entries) | PASID_PTE_PRESENT);
+ }
+ spin_unlock(&pasid_lock);

- return &entries[pasid];
+ return &entries[index];
}

/*
@@ -224,7 +273,14 @@ struct pasid_entry *intel_pasid_get_entry(struct device *dev, int pasid)
*/
static inline void pasid_clear_entry(struct pasid_entry *pe)
{
- WRITE_ONCE(pe->val, 0);
+ WRITE_ONCE(pe->val[0], 0);
+ WRITE_ONCE(pe->val[1], 0);
+ WRITE_ONCE(pe->val[2], 0);
+ WRITE_ONCE(pe->val[3], 0);
+ WRITE_ONCE(pe->val[4], 0);
+ WRITE_ONCE(pe->val[5], 0);
+ WRITE_ONCE(pe->val[6], 0);
+ WRITE_ONCE(pe->val[7], 0);
}

void intel_pasid_clear_entry(struct device *dev, int pasid)
diff --git a/drivers/iommu/intel-pasid.h b/drivers/iommu/intel-pasid.h
index 1fb5e12b029a..12f480c2bb8b 100644
--- a/drivers/iommu/intel-pasid.h
+++ b/drivers/iommu/intel-pasid.h
@@ -11,12 +11,20 @@
#define __INTEL_PASID_H

#define PASID_MIN 0x1
-#define PASID_MAX 0x20000
+#define PASID_MAX 0x100000
+#define PASID_PTE_MASK 0x3F
+#define PASID_PTE_PRESENT 1
+#define PDE_PFN_MASK PAGE_MASK
+#define PASID_PDE_SHIFT 6

-struct pasid_entry {
+struct pasid_dir_entry {
u64 val;
};

+struct pasid_entry {
+ u64 val[8];
+};
+
/* The representative of a PASID table */
struct pasid_table {
void *table; /* pasid table pointer */
diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index 887150907526..9014b07ab975 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -65,8 +65,6 @@ int intel_svm_init(struct intel_iommu *iommu)

order = get_order(sizeof(struct pasid_entry) * iommu->pasid_max);
if (ecap_dis(iommu->ecap)) {
- /* Just making it explicit... */
- BUILD_BUG_ON(sizeof(struct pasid_entry) != sizeof(struct pasid_state_entry));
pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
if (pages)
iommu->pasid_state_table = page_address(pages);
@@ -405,9 +403,7 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_
pasid_entry_val |= PASID_ENTRY_FLPM_5LP;

entry = intel_pasid_get_entry(dev, svm->pasid);
- entry->val = pasid_entry_val;
-
- wmb();
+ WRITE_ONCE(entry->val[0], pasid_entry_val);

/*
* Flush PASID cache when a PASID table entry becomes
--
2.17.1
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