From e5afdf9dd515a9446c009f44f99f9bc2f91b89a7 Mon Sep 17 00:00:00 2001 From: Alexey Kardashevskiy Date: Wed, 22 Mar 2017 15:21:50 +1100 Subject: [PATCH] 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 Reviewed-by: David Gibson Acked-by: Alex Williamson Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/iommu.h | 5 +++-- arch/powerpc/kernel/iommu.c | 27 ++++++++++++++++++----- 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, 37 insertions(+), 17 deletions(-) diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h index 4554699aec02..d96142572e6d 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 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 diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c index a3689fdedd4a..5a3231fedf08 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 +748,24 @@ 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 diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c index 5dae54cb11e3..ee4cdb5b893f 100644 --- a/arch/powerpc/platforms/powernv/pci-ioda.c +++ b/arch/powerpc/platforms/powernv/pci-ioda.c @@ -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, diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c index eb835e977e33..204a829ff506 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 4d757eaa46bf..7ce5db209abf 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_tce_table_put(tbl); kfree(table_group); } diff --git a/arch/powerpc/platforms/pseries/vio.c b/arch/powerpc/platforms/pseries/vio.c index 720493932486..28b09fd797ec 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_tce_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 fbec7348a7e5..8031d3a55a17 100644 --- a/drivers/vfio/vfio_iommu_spapr_tce.c +++ b/drivers/vfio/vfio_iommu_spapr_tce.c @@ -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); }