powerpc/vfio_spapr_tce: Add reference counting to iommu_table

So far iommu_table obejcts were only used in virtual mode and had
a single owner. We are going to change this by implementing in-kernel
acceleration of DMA mapping requests. The proposed acceleration
will handle requests in real mode and KVM will keep references to tables.

This adds a kref to iommu_table and defines new helpers to update it.
This replaces iommu_free_table() with iommu_tce_table_put() and makes
iommu_free_table() static. iommu_tce_table_get() is not used in this patch
but it will be in the following patch.

Since this touches prototypes, this also removes @node_name parameter as
it has never been really useful on powernv and carrying it for
the pseries platform code to iommu_free_table() seems to be quite
useless as well.

This should cause no behavioral change.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Alexey Kardashevskiy 2017-03-22 15:21:50 +11:00 committed by Michael Ellerman
parent 11edf116e3
commit e5afdf9dd5
7 changed files with 37 additions and 17 deletions

View File

@ -119,6 +119,7 @@ struct iommu_table {
struct list_head it_group_list;/* List of iommu_table_group_link */
unsigned long *it_userspace; /* userspace view of the table */
struct iommu_table_ops *it_ops;
struct kref it_kref;
};
#define IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry) \
@ -151,8 +152,8 @@ static inline void *get_iommu_table_base(struct device *dev)
extern int dma_iommu_dma_supported(struct device *dev, u64 mask);
/* Frees table for an individual device node */
extern void iommu_free_table(struct iommu_table *tbl, const char *node_name);
extern struct iommu_table *iommu_tce_table_get(struct iommu_table *tbl);
extern int iommu_tce_table_put(struct iommu_table *tbl);
/* Initializes an iommu_table based in values set in the passed-in
* structure

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@ -711,13 +711,13 @@ struct iommu_table *iommu_init_table(struct iommu_table *tbl, int nid)
return tbl;
}
void iommu_free_table(struct iommu_table *tbl, const char *node_name)
static void iommu_table_free(struct kref *kref)
{
unsigned long bitmap_sz;
unsigned int order;
struct iommu_table *tbl;
if (!tbl)
return;
tbl = container_of(kref, struct iommu_table, it_kref);
if (tbl->it_ops->free)
tbl->it_ops->free(tbl);
@ -736,7 +736,7 @@ void iommu_free_table(struct iommu_table *tbl, const char *node_name)
/* verify that table contains no entries */
if (!bitmap_empty(tbl->it_map, tbl->it_size))
pr_warn("%s: Unexpected TCEs for %s\n", __func__, node_name);
pr_warn("%s: Unexpected TCEs\n", __func__);
/* calculate bitmap size in bytes */
bitmap_sz = BITS_TO_LONGS(tbl->it_size) * sizeof(unsigned long);
@ -748,7 +748,24 @@ void iommu_free_table(struct iommu_table *tbl, const char *node_name)
/* free table */
kfree(tbl);
}
EXPORT_SYMBOL_GPL(iommu_free_table);
struct iommu_table *iommu_tce_table_get(struct iommu_table *tbl)
{
if (kref_get_unless_zero(&tbl->it_kref))
return tbl;
return NULL;
}
EXPORT_SYMBOL_GPL(iommu_tce_table_get);
int iommu_tce_table_put(struct iommu_table *tbl)
{
if (WARN_ON(!tbl))
return 0;
return kref_put(&tbl->it_kref, iommu_table_free);
}
EXPORT_SYMBOL_GPL(iommu_tce_table_put);
/* Creates TCEs for a user provided buffer. The user buffer must be
* contiguous real kernel storage (not vmalloc). The address passed here

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@ -1424,7 +1424,7 @@ static void pnv_pci_ioda2_release_dma_pe(struct pci_dev *dev, struct pnv_ioda_pe
iommu_group_put(pe->table_group.group);
BUG_ON(pe->table_group.group);
}
iommu_free_table(tbl, of_node_full_name(dev->dev.of_node));
iommu_tce_table_put(tbl);
}
static void pnv_ioda_release_vf_PE(struct pci_dev *pdev)
@ -2225,7 +2225,7 @@ found:
__free_pages(tce_mem, get_order(tce32_segsz * segs));
if (tbl) {
pnv_pci_unlink_table_and_group(tbl, &pe->table_group);
iommu_free_table(tbl, "pnv");
iommu_tce_table_put(tbl);
}
}
@ -2321,7 +2321,7 @@ static long pnv_pci_ioda2_create_table(struct iommu_table_group *table_group,
bus_offset, page_shift, window_size,
levels, tbl);
if (ret) {
iommu_free_table(tbl, "pnv");
iommu_tce_table_put(tbl);
return ret;
}
@ -2365,7 +2365,7 @@ static long pnv_pci_ioda2_setup_default_config(struct pnv_ioda_pe *pe)
if (rc) {
pe_err(pe, "Failed to configure 32-bit TCE table, err %ld\n",
rc);
iommu_free_table(tbl, "");
iommu_tce_table_put(tbl);
return rc;
}
@ -2453,7 +2453,7 @@ static void pnv_ioda2_take_ownership(struct iommu_table_group *table_group)
pnv_pci_ioda2_unset_window(&pe->table_group, 0);
if (pe->pbus)
pnv_ioda_setup_bus_dma(pe, pe->pbus, false);
iommu_free_table(tbl, "pnv");
iommu_tce_table_put(tbl);
}
static void pnv_ioda2_release_ownership(struct iommu_table_group *table_group)
@ -3428,7 +3428,7 @@ static void pnv_pci_ioda1_release_pe_dma(struct pnv_ioda_pe *pe)
}
free_pages(tbl->it_base, get_order(tbl->it_size << 3));
iommu_free_table(tbl, "pnv");
iommu_tce_table_put(tbl);
}
static void pnv_pci_ioda2_release_pe_dma(struct pnv_ioda_pe *pe)
@ -3455,7 +3455,7 @@ static void pnv_pci_ioda2_release_pe_dma(struct pnv_ioda_pe *pe)
}
pnv_pci_ioda2_table_free_pages(tbl);
iommu_free_table(tbl, "pnv");
iommu_tce_table_put(tbl);
}
static void pnv_ioda_free_pe_seg(struct pnv_ioda_pe *pe,

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@ -767,6 +767,7 @@ struct iommu_table *pnv_pci_table_alloc(int nid)
tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL, nid);
INIT_LIST_HEAD_RCU(&tbl->it_group_list);
kref_init(&tbl->it_kref);
return tbl;
}

View File

@ -74,6 +74,7 @@ static struct iommu_table_group *iommu_pseries_alloc_group(int node)
goto fail_exit;
INIT_LIST_HEAD_RCU(&tbl->it_group_list);
kref_init(&tbl->it_kref);
tgl->table_group = table_group;
list_add_rcu(&tgl->next, &tbl->it_group_list);
@ -115,7 +116,7 @@ static void iommu_pseries_free_group(struct iommu_table_group *table_group,
BUG_ON(table_group->group);
}
#endif
iommu_free_table(tbl, node_name);
iommu_tce_table_put(tbl);
kfree(table_group);
}

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@ -1318,7 +1318,7 @@ static void vio_dev_release(struct device *dev)
struct iommu_table *tbl = get_iommu_table_base(dev);
if (tbl)
iommu_free_table(tbl, of_node_full_name(dev->of_node));
iommu_tce_table_put(tbl);
of_node_put(dev->of_node);
kfree(to_vio_dev(dev));
}

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@ -680,7 +680,7 @@ static void tce_iommu_free_table(struct tce_container *container,
unsigned long pages = tbl->it_allocated_size >> PAGE_SHIFT;
tce_iommu_userspace_view_free(tbl, container->mm);
iommu_free_table(tbl, "");
iommu_tce_table_put(tbl);
decrement_locked_vm(container->mm, pages);
}