[PATCH kernel v5 04/10] powerpc/vfio_spapr_tce: Add reference counting to iommu_table
From: Alexey Kardashevskiy <hidden>
Date: 2017-02-22 08:22:16
Also in:
kvm
Subsystem:
ibm power vfio support, linux for powerpc (32-bit and 64-bit), the rest, vfio driver · Maintainers:
Timothy Pearson, Madhavan Srinivasan, Michael Ellerman, Linus Torvalds, Alex Williamson
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_table_put() and makes iommu_free_table() static. iommu_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 <redacted> Reviewed-by: David Gibson <redacted> --- arch/powerpc/include/asm/iommu.h | 5 +++-- arch/powerpc/kernel/iommu.c | 24 +++++++++++++++++++----- arch/powerpc/platforms/powernv/pci-ioda.c | 14 +++++++------- arch/powerpc/platforms/powernv/pci.c | 1 + arch/powerpc/platforms/pseries/iommu.c | 3 ++- arch/powerpc/platforms/pseries/vio.c | 2 +- drivers/vfio/vfio_iommu_spapr_tce.c | 2 +- 7 files changed, 34 insertions(+), 17 deletions(-)
diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index 4554699aec02..82e77ebf85f4 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h@@ -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 void iommu_table_get(struct iommu_table *tbl); +extern void iommu_table_put(struct iommu_table *tbl); /* Initializes an iommu_table based in values set in the passed-in * structure
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index bc142d87130f..d02b8d22fb50 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c@@ -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 +748,21 @@ void iommu_free_table(struct iommu_table *tbl, const char *node_name) /* free table */ kfree(tbl); } -EXPORT_SYMBOL_GPL(iommu_free_table); + +void iommu_table_get(struct iommu_table *tbl) +{ + kref_get(&tbl->it_kref); +} +EXPORT_SYMBOL_GPL(iommu_table_get); + +void iommu_table_put(struct iommu_table *tbl) +{ + if (!tbl) + return; + + kref_put(&tbl->it_kref, iommu_table_free); +} +EXPORT_SYMBOL_GPL(iommu_table_put); /* Creates TCEs for a user provided buffer. The user buffer must be * contiguous real kernel storage (not vmalloc). The address passed here
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 27801c61ebdb..db3aea42e8b5 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c@@ -1423,7 +1423,7 @@ 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_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_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_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_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_table_put(tbl); } static void pnv_ioda2_release_ownership(struct iommu_table_group *table_group)
@@ -3426,7 +3426,7 @@ 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_table_put(tbl); } static void pnv_pci_ioda2_release_pe_dma(struct pnv_ioda_pe *pe)
@@ -3453,7 +3453,7 @@ 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_table_put(tbl); } static void pnv_ioda_free_pe_seg(struct pnv_ioda_pe *pe,
diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
index 3f7f267a3d04..6dec900465ce 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c@@ -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; }
diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index dc2577fc5fbb..47f0501a94f9 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c@@ -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_table_put(tbl); kfree(table_group); }
diff --git a/arch/powerpc/platforms/pseries/vio.c b/arch/powerpc/platforms/pseries/vio.c
index 2c8fb3ec989e..41e8aa5c0d6a 100644
--- a/arch/powerpc/platforms/pseries/vio.c
+++ b/arch/powerpc/platforms/pseries/vio.c@@ -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_table_put(tbl); of_node_put(dev->of_node); kfree(to_vio_dev(dev)); }
diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index ffab01874a22..b0d455cc7776 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c@@ -677,7 +677,7 @@ 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_table_put(tbl); decrement_locked_vm(container->mm, pages); }
--
2.11.0