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Commit e5afdf9d authored by Alexey Kardashevskiy's avatar Alexey Kardashevskiy Committed by Michael Ellerman
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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: default avatarAlexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
Acked-by: default avatarAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 11edf116

arch/powerpc/include/asm/iommu.h

+3 −2
Original line number Diff line number Diff line
@@ -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

arch/powerpc/kernel/iommu.c

+22 −5
Original line number Diff line number Diff line
@@ -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

arch/powerpc/platforms/powernv/pci-ioda.c

+7 −7
Original line number Diff line number Diff line
@@ -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 @@ static void pnv_pci_ioda1_setup_dma_pe(struct pnv_phb *phb, 
		__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,

arch/powerpc/platforms/powernv/pci.c

+1 −0
Original line number Diff line number Diff line
@@ -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;

}

arch/powerpc/platforms/pseries/iommu.c

+2 −1
Original line number Diff line number Diff line
@@ -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);

}