Messages in this thread | | | Date | Wed, 29 Apr 2015 13:02:50 +1000 | From | David Gibson <> | Subject | Re: [PATCH kernel v9 13/32] vfio: powerpc/spapr/iommu/powernv/ioda2: Rework IOMMU ownership control |
| |
On Sat, Apr 25, 2015 at 10:14:37PM +1000, Alexey Kardashevskiy wrote: > 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. > > Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> > [aw: for the vfio related changes] > Acked-by: Alex Williamson <alex.williamson@redhat.com> > --- > Changes: > v9: > * squashed "vfio: powerpc/spapr: powerpc/iommu: Rework IOMMU ownership control" > and "vfio: powerpc/spapr: powerpc/powernv/ioda2: Rework IOMMU ownership control" > into a single patch > * moved helpers with a loop through tables in a group > to vfio_iommu_spapr_tce.c to keep the platform code free of IOMMU table > groups as much as possible > * added missing tce_iommu_clear() to tce_iommu_release_ownership() > * replaced the set_ownership(enable) callback with take_ownership() and > release_ownership() > --- > arch/powerpc/include/asm/iommu.h | 13 +++++- > arch/powerpc/kernel/iommu.c | 11 ------ > arch/powerpc/platforms/powernv/pci-ioda.c | 40 +++++++++++++++---- > drivers/vfio/vfio_iommu_spapr_tce.c | 66 +++++++++++++++++++++++++++---- > 4 files changed, 103 insertions(+), 27 deletions(-) > > diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h > index fa37519..e63419e 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 iommu_table_group *it_table_group; > struct iommu_table_ops *it_ops; > - void (*set_bypass)(struct iommu_table *tbl, bool enable); > }; > > /* Pure 2^n version of get_order */ > @@ -128,11 +127,23 @@ extern struct iommu_table *iommu_init_table(struct iommu_table * tbl, > > #define IOMMU_TABLE_GROUP_MAX_TABLES 1 > > +struct iommu_table_group; > + > +struct iommu_table_group_ops { > + /* > + * Switches ownership from the kernel itself to an external > + * user. While onwership is taken, the kernel cannot use IOMMU itself.
Typo in "onwership". I'd also like to see this be even more explicit that "take" is the "core kernel -> vfio/whatever" transition and release is the reverse.
> + */ > + void (*take_ownership)(struct iommu_table_group *table_group); > + void (*release_ownership)(struct iommu_table_group *table_group); > +}; > + > struct iommu_table_group { > #ifdef CONFIG_IOMMU_API > struct iommu_group *group; > #endif > 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 005146b..2856d27 100644 > --- a/arch/powerpc/kernel/iommu.c > +++ b/arch/powerpc/kernel/iommu.c > @@ -1057,13 +1057,6 @@ 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; > } > @@ -1078,10 +1071,6 @@ 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 88472cb..718d5cc 100644 > --- a/arch/powerpc/platforms/powernv/pci-ioda.c > +++ b/arch/powerpc/platforms/powernv/pci-ioda.c > @@ -1870,10 +1870,8 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb, > __free_pages(tce_mem, get_order(TCE32_TABLE_SIZE * segs)); > } > > -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 pnv_ioda_pe *pe = container_of(tbl->it_table_group, > - struct pnv_ioda_pe, table_group); > uint16_t window_id = (pe->pe_number << 1 ) + 1; > int64_t rc; > > @@ -1901,7 +1899,8 @@ static void pnv_pci_ioda2_set_bypass(struct iommu_table *tbl, bool enable) > * host side. > */ > if (pe->pdev) > - set_iommu_table_base(&pe->pdev->dev, tbl); > + set_iommu_table_base(&pe->pdev->dev, > + &pe->table_group.tables[0]); > else > pnv_ioda_setup_bus_dma(pe, pe->pbus, false); > } > @@ -1917,13 +1916,35 @@ static void pnv_pci_ioda2_setup_bypass_pe(struct pnv_phb *phb, > /* TVE #1 is selected by PCI address bit 59 */ > pe->tce_bypass_base = 1ull << 59; > > - /* Install set_bypass callback for VFIO */ > - pe->table_group.tables[0].set_bypass = pnv_pci_ioda2_set_bypass; > - > /* Enable bypass by default */ > - pnv_pci_ioda2_set_bypass(&pe->table_group.tables[0], true); > + pnv_pci_ioda2_set_bypass(pe, true); > } > > +#ifdef CONFIG_IOMMU_API > +static void pnv_ioda2_take_ownership(struct iommu_table_group *table_group) > +{ > + struct pnv_ioda_pe *pe = container_of(table_group, struct pnv_ioda_pe, > + table_group); > + > + iommu_take_ownership(&table_group->tables[0]); > + pnv_pci_ioda2_set_bypass(pe, false); > +} > + > +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) > { > @@ -1991,6 +2012,9 @@ 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) { > iommu_register_group(&pe->table_group, phb->hose->global_number, > diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c > index 17e884a..dacc738 100644 > --- a/drivers/vfio/vfio_iommu_spapr_tce.c > +++ b/drivers/vfio/vfio_iommu_spapr_tce.c > @@ -483,6 +483,43 @@ 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]; > + > + 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 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->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 int tce_iommu_attach_group(void *iommu_data, > struct iommu_group *iommu_group) > { > @@ -515,9 +552,23 @@ static int tce_iommu_attach_group(void *iommu_data, > goto unlock_exit; > } > > - ret = iommu_take_ownership(&table_group->tables[0]); > - if (!ret) > - container->grp = iommu_group; > + if (!table_group->ops || !table_group->ops->take_ownership || > + !table_group->ops->release_ownership) { > + ret = tce_iommu_take_ownership(table_group);
Haven't looked at the rest of the series. I'm hoping that you're eventually planning to replace this fallback with setting the take_ownership call for p5ioc etc. to point to tce_iommu_take_ownership.
> + } else { > + /* > + * 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 > + */ > + table_group->ops->take_ownership(table_group); > + ret = 0; > + } > + > + if (ret) > + goto unlock_exit; > + > + container->grp = iommu_group; > > unlock_exit: > mutex_unlock(&container->lock); > @@ -530,7 +581,6 @@ 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) { > @@ -553,9 +603,11 @@ 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); > + /* Kernel owns the device now, we can restore bypass */ > + if (!table_group->ops || !table_group->ops->release_ownership) > + tce_iommu_release_ownership(container, table_group); > + else > + table_group->ops->release_ownership(table_group); > > unlock_exit: > mutex_unlock(&container->lock);
-- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson [unhandled content-type:application/pgp-signature] | |