From f87a88642e660edd8912ad39fe77848c6f9927a2 Mon Sep 17 00:00:00 2001 From: Alexey Kardashevskiy Date: Fri, 5 Jun 2015 16:35:10 +1000 Subject: [PATCH] vfio: powerpc/spapr/iommu/powernv/ioda2: Rework IOMMU ownership control This adds tce_iommu_take_ownership() and tce_iommu_release_ownership which call in a loop iommu_take_ownership()/iommu_release_ownership() for every table on the group. As there is just one now, no change in behaviour is expected. At the moment the iommu_table struct has a set_bypass() which enables/ disables DMA bypass on IODA2 PHB. This is exposed to POWERPC IOMMU code which calls this callback when external IOMMU users such as VFIO are about to get over a PHB. The set_bypass() callback is not really an iommu_table function but IOMMU/PE function. This introduces a iommu_table_group_ops struct and adds take_ownership()/release_ownership() callbacks to it which are called when an external user takes/releases control over the IOMMU. This replaces set_bypass() with ownership callbacks as it is not necessarily just bypass enabling, it can be something else/more so let's give it more generic name. The callbacks is implemented for IODA2 only. Other platforms (P5IOC2, IODA1) will use the old iommu_take_ownership/iommu_release_ownership API. The following patches will replace iommu_take_ownership/ iommu_release_ownership calls in IODA2 with full IOMMU table release/ create. As we here and touching bypass control, this removes pnv_pci_ioda2_setup_bypass_pe() as it does not do much more compared to pnv_pci_ioda2_set_bypass. This moves tce_bypass_base initialization to pnv_pci_ioda2_setup_dma_pe. Signed-off-by: Alexey Kardashevskiy [aw: for the vfio related changes] Acked-by: Alex Williamson Reviewed-by: Gavin Shan Reviewed-by: David Gibson Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/iommu.h | 11 +++- arch/powerpc/kernel/iommu.c | 12 ---- arch/powerpc/platforms/powernv/pci-ioda.c | 43 +++++++++----- drivers/vfio/vfio_iommu_spapr_tce.c | 70 +++++++++++++++++++++-- 4 files changed, 103 insertions(+), 33 deletions(-) diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h index 44a20ccf06b4..489133cf7c5e 100644 --- a/arch/powerpc/include/asm/iommu.h +++ b/arch/powerpc/include/asm/iommu.h @@ -93,7 +93,6 @@ struct iommu_table { unsigned long it_page_shift;/* table iommu page size */ struct list_head it_group_list;/* List of iommu_table_group_link */ struct iommu_table_ops *it_ops; - void (*set_bypass)(struct iommu_table *tbl, bool enable); }; /* Pure 2^n version of get_order */ @@ -126,6 +125,15 @@ extern struct iommu_table *iommu_init_table(struct iommu_table * tbl, int nid); #define IOMMU_TABLE_GROUP_MAX_TABLES 1 +struct iommu_table_group; + +struct iommu_table_group_ops { + /* Switch ownership from platform code to external user (e.g. VFIO) */ + void (*take_ownership)(struct iommu_table_group *table_group); + /* Switch ownership from external user (e.g. VFIO) back to core */ + void (*release_ownership)(struct iommu_table_group *table_group); +}; + struct iommu_table_group_link { struct list_head next; struct rcu_head rcu; @@ -135,6 +143,7 @@ struct iommu_table_group_link { struct iommu_table_group { struct iommu_group *group; struct iommu_table *tables[IOMMU_TABLE_GROUP_MAX_TABLES]; + struct iommu_table_group_ops *ops; }; #ifdef CONFIG_IOMMU_API diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c index be258b2ecb10..e7f81b7399ba 100644 --- a/arch/powerpc/kernel/iommu.c +++ b/arch/powerpc/kernel/iommu.c @@ -1047,14 +1047,6 @@ int iommu_take_ownership(struct iommu_table *tbl) memset(tbl->it_map, 0xff, sz); - /* - * Disable iommu bypass, otherwise the user can DMA to all of - * our physical memory via the bypass window instead of just - * the pages that has been explicitly mapped into the iommu - */ - if (tbl->set_bypass) - tbl->set_bypass(tbl, false); - return 0; } EXPORT_SYMBOL_GPL(iommu_take_ownership); @@ -1068,10 +1060,6 @@ void iommu_release_ownership(struct iommu_table *tbl) /* Restore bit#0 set by iommu_init_table() */ if (tbl->it_offset == 0) set_bit(0, tbl->it_map); - - /* The kernel owns the device now, we can restore the iommu bypass */ - if (tbl->set_bypass) - tbl->set_bypass(tbl, true); } EXPORT_SYMBOL_GPL(iommu_release_ownership); diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c index 3b4130697b05..17a77522ea0d 100644 --- a/arch/powerpc/platforms/powernv/pci-ioda.c +++ b/arch/powerpc/platforms/powernv/pci-ioda.c @@ -1919,13 +1919,8 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb, } } -static void pnv_pci_ioda2_set_bypass(struct iommu_table *tbl, bool enable) +static void pnv_pci_ioda2_set_bypass(struct pnv_ioda_pe *pe, bool enable) { - struct iommu_table_group_link *tgl = list_first_entry_or_null( - &tbl->it_group_list, struct iommu_table_group_link, - next); - struct pnv_ioda_pe *pe = container_of(tgl->table_group, - struct pnv_ioda_pe, table_group); uint16_t window_id = (pe->pe_number << 1 ) + 1; int64_t rc; @@ -1952,19 +1947,31 @@ static void pnv_pci_ioda2_set_bypass(struct iommu_table *tbl, bool enable) pe->tce_bypass_enabled = enable; } -static void pnv_pci_ioda2_setup_bypass_pe(struct pnv_phb *phb, - struct pnv_ioda_pe *pe) +#ifdef CONFIG_IOMMU_API +static void pnv_ioda2_take_ownership(struct iommu_table_group *table_group) { - /* TVE #1 is selected by PCI address bit 59 */ - pe->tce_bypass_base = 1ull << 59; + struct pnv_ioda_pe *pe = container_of(table_group, struct pnv_ioda_pe, + table_group); - /* Install set_bypass callback for VFIO */ - pe->table_group.tables[0]->set_bypass = pnv_pci_ioda2_set_bypass; + iommu_take_ownership(table_group->tables[0]); + pnv_pci_ioda2_set_bypass(pe, false); +} - /* Enable bypass by default */ - pnv_pci_ioda2_set_bypass(pe->table_group.tables[0], true); +static void pnv_ioda2_release_ownership(struct iommu_table_group *table_group) +{ + struct pnv_ioda_pe *pe = container_of(table_group, struct pnv_ioda_pe, + table_group); + + iommu_release_ownership(table_group->tables[0]); + pnv_pci_ioda2_set_bypass(pe, true); } +static struct iommu_table_group_ops pnv_pci_ioda2_ops = { + .take_ownership = pnv_ioda2_take_ownership, + .release_ownership = pnv_ioda2_release_ownership, +}; +#endif + static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb, struct pnv_ioda_pe *pe) { @@ -1979,6 +1986,9 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb, if (WARN_ON(pe->tce32_seg >= 0)) return; + /* TVE #1 is selected by PCI address bit 59 */ + pe->tce_bypass_base = 1ull << 59; + tbl = pnv_pci_table_alloc(phb->hose->node); iommu_register_group(&pe->table_group, phb->hose->global_number, pe->pe_number); @@ -2033,6 +2043,9 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb, } tbl->it_ops = &pnv_ioda2_iommu_ops; iommu_init_table(tbl, phb->hose->node); +#ifdef CONFIG_IOMMU_API + pe->table_group.ops = &pnv_pci_ioda2_ops; +#endif if (pe->flags & PNV_IODA_PE_DEV) { /* @@ -2047,7 +2060,7 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb, /* Also create a bypass window */ if (!pnv_iommu_bypass_disabled) - pnv_pci_ioda2_setup_bypass_pe(phb, pe); + pnv_pci_ioda2_set_bypass(pe, true); return; fail: diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c index ffc634a75dba..9c720de46c33 100644 --- a/drivers/vfio/vfio_iommu_spapr_tce.c +++ b/drivers/vfio/vfio_iommu_spapr_tce.c @@ -486,6 +486,61 @@ static long tce_iommu_ioctl(void *iommu_data, return -ENOTTY; } +static void tce_iommu_release_ownership(struct tce_container *container, + struct iommu_table_group *table_group) +{ + int i; + + for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) { + struct iommu_table *tbl = table_group->tables[i]; + + if (!tbl) + continue; + + tce_iommu_clear(container, tbl, tbl->it_offset, tbl->it_size); + if (tbl->it_map) + iommu_release_ownership(tbl); + } +} + +static int tce_iommu_take_ownership(struct tce_container *container, + struct iommu_table_group *table_group) +{ + int i, j, rc = 0; + + for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) { + struct iommu_table *tbl = table_group->tables[i]; + + if (!tbl || !tbl->it_map) + continue; + + rc = iommu_take_ownership(tbl); + if (rc) { + for (j = 0; j < i; ++j) + iommu_release_ownership( + table_group->tables[j]); + + return rc; + } + } + + return 0; +} + +static void tce_iommu_release_ownership_ddw(struct tce_container *container, + struct iommu_table_group *table_group) +{ + table_group->ops->release_ownership(table_group); +} + +static long tce_iommu_take_ownership_ddw(struct tce_container *container, + struct iommu_table_group *table_group) +{ + table_group->ops->take_ownership(table_group); + + return 0; +} + static int tce_iommu_attach_group(void *iommu_data, struct iommu_group *iommu_group) { @@ -518,7 +573,12 @@ static int tce_iommu_attach_group(void *iommu_data, goto unlock_exit; } - ret = iommu_take_ownership(table_group->tables[0]); + if (!table_group->ops || !table_group->ops->take_ownership || + !table_group->ops->release_ownership) + ret = tce_iommu_take_ownership(container, table_group); + else + ret = tce_iommu_take_ownership_ddw(container, table_group); + if (!ret) container->grp = iommu_group; @@ -533,7 +593,6 @@ static void tce_iommu_detach_group(void *iommu_data, { struct tce_container *container = iommu_data; struct iommu_table_group *table_group; - struct iommu_table *tbl; mutex_lock(&container->lock); if (iommu_group != container->grp) { @@ -556,9 +615,10 @@ static void tce_iommu_detach_group(void *iommu_data, table_group = iommu_group_get_iommudata(iommu_group); BUG_ON(!table_group); - tbl = table_group->tables[0]; - tce_iommu_clear(container, tbl, tbl->it_offset, tbl->it_size); - iommu_release_ownership(tbl); + if (!table_group->ops || !table_group->ops->release_ownership) + tce_iommu_release_ownership(container, table_group); + else + tce_iommu_release_ownership_ddw(container, table_group); unlock_exit: mutex_unlock(&container->lock); -- 2.20.1