Subject: [RFC PATCH v4 0/8] Introduce automatic DMA configuration for IOMMU masters

From: [email-masked] (Will Deacon)
Date: Wed, 21 Jan 2015 14:48:35 +0000

On Tue, Jan 20, 2015 at 04:56:03PM +0000, Laurent Pinchart wrote:
> Hi Will,

Hi Laurent,

> Thank you for the patch.
> 
> On Monday 19 January 2015 16:06:20 Will Deacon wrote:
> > (resurrecting an old thread)
> >
> > On Fri, Nov 14, 2014 at 08:01:56PM +0000, Arnd Bergmann wrote:
> > > On Friday 14 November 2014 19:27:54 Will Deacon wrote:
> > > > > At the moment, iommu_ops is a structure that can get used for any
> > > > > number of iommus of the same type, but by putting per-device private
> > > > > data into the same structure you have to duplicate it per instance.
> > > >
> > > > I'm not sure I agree -- the pgsize_bitmap, for example, could vary
> > > > between different implementations of the same IOMMU. I think we already
> > > > have this in Juno (some SMMUs can only do 64k pages, whilst others can
> > > > do 4k and 64k).
> > >
> > > Ah, I hadn't noticed that, it should be in the 'struct iommu' then of
> > > course, not in iommu_ops.
> >
> > Now that of_iommu_get_ops has its own list of iommu_ops, we can actually
> > just move pgsize_bitmap into the iommu_domain, which I think makes a lot
> > more sense anyway.
> 
> The code looks good to me, but what does it have to do with of_iommu_get_ops()
> having its own list of iommu_ops ?

So, the initial patches for of_iommu_configure/of_xlate made use of a void
*priv field in struct iommu_ops (which actually made it to mainline but
isn't used). This was replaced by the list maintained by of_iommu_get_ops,
but the discussion highlighted that iommu_ops is not per-IOMMU instance and
therefore shouldn't contain the pgsize_bitmap, which can (and does) vary
between different IOMMU instances in a running system.

This patch is an effort to move the pgsize_bitmap field out of iommu_ops
(leaving that structure to contain only function pointers) and into
iommu_domain, where I think it makes more sense.

Will

> > diff below seems to do the trick. The next step would be postponing the
> > pgsize_bitmap initialisation until device attach for the ARM SMMU, since
> > it's at that point that we know the active page table format (and
> > therefore the supported page sizes).
> >
> > Will
> >
> > --->8
> >
> > diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
> > index 98024856df07..ab9702d01e9a 100644
> > --- a/drivers/iommu/amd_iommu.c
> > +++ b/drivers/iommu/amd_iommu.c
> > @@ -3257,6 +3257,7 @@ static int amd_iommu_domain_init(struct iommu_domain
> > *dom) dom->geometry.aperture_end   = ~0ULL;
> >       dom->geometry.force_aperture = true;
> >
> > +     dom->pgsize_bitmap = AMD_IOMMU_PGSIZES;
> >       return 0;
> >
> >  out_free:
> > @@ -3428,7 +3429,6 @@ static const struct iommu_ops amd_iommu_ops = {
> >       .unmap = amd_iommu_unmap,
> >       .map_sg = default_iommu_map_sg,
> >       .iova_to_phys = amd_iommu_iova_to_phys,
> > -     .pgsize_bitmap  = AMD_IOMMU_PGSIZES,
> >  };
> >
> >  /**************************************************************************
> > *** diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> > index 6cd47b75286f..898fab8d10a0 100644
> > --- a/drivers/iommu/arm-smmu.c
> > +++ b/drivers/iommu/arm-smmu.c
> > @@ -1033,6 +1033,9 @@ static int arm_smmu_domain_init(struct iommu_domain
> > *domain)
> >
> >       spin_lock_init(&smmu_domain->lock);
> >       domain->priv = smmu_domain;
> > +     domain->pgsize_bitmap = (SECTION_SIZE |
> > +                              ARM_SMMU_PTE_CONT_SIZE |
> > +                              PAGE_SIZE);
> >       return 0;
> >
> >  out_free_domain:
> > @@ -1729,9 +1732,6 @@ static const struct iommu_ops arm_smmu_ops = {
> >       .remove_device          = arm_smmu_remove_device,
> >       .domain_get_attr        = arm_smmu_domain_get_attr,
> >       .domain_set_attr        = arm_smmu_domain_set_attr,
> > -     .pgsize_bitmap          = (SECTION_SIZE |
> > -                                ARM_SMMU_PTE_CONT_SIZE |
> > -                                PAGE_SIZE),
> >  };
> >
> >  static void arm_smmu_device_reset(struct arm_smmu_device *smmu)
> > diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
> > index 7ce52737c7a1..404cad25db9b 100644
> > --- a/drivers/iommu/exynos-iommu.c
> > +++ b/drivers/iommu/exynos-iommu.c
> > @@ -735,6 +735,8 @@ static int exynos_iommu_domain_init(struct iommu_domain
> > *domain) domain->geometry.aperture_end   = ~0UL;
> >       domain->geometry.force_aperture = true;
> >
> > +     domain->pgsize_bitmap = SECT_SIZE | LPAGE_SIZE | SPAGE_SIZE;
> > +
> >       domain->priv = priv;
> >       return 0;
> >
> > @@ -1181,7 +1183,6 @@ static const struct iommu_ops exynos_iommu_ops = {
> >       .iova_to_phys = exynos_iommu_iova_to_phys,
> >       .add_device = exynos_iommu_add_device,
> >       .remove_device = exynos_iommu_remove_device,
> > -     .pgsize_bitmap = SECT_SIZE | LPAGE_SIZE | SPAGE_SIZE,
> >  };
> >
> >  static int __init exynos_iommu_init(void)
> > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> > index 40dfbc0444c0..e2b0f34baa9d 100644
> > --- a/drivers/iommu/intel-iommu.c
> > +++ b/drivers/iommu/intel-iommu.c
> > @@ -4386,6 +4386,7 @@ static int intel_iommu_domain_init(struct iommu_domain
> > *domain) domain->geometry.aperture_end   =
> > __DOMAIN_MAX_ADDR(dmar_domain->gaw); domain->geometry.force_aperture =
> > true;
> >
> > +     domain->pgsize_bitmap = INTEL_IOMMU_PGSIZES;
> >       return 0;
> >  }
> >
> > @@ -4628,7 +4629,6 @@ static const struct iommu_ops intel_iommu_ops = {
> >       .iova_to_phys   = intel_iommu_iova_to_phys,
> >       .add_device     = intel_iommu_add_device,
> >       .remove_device  = intel_iommu_remove_device,
> > -     .pgsize_bitmap  = INTEL_IOMMU_PGSIZES,
> >  };
> >
> >  static void quirk_iommu_g4x_gfx(struct pci_dev *dev)
> > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> > index f7718d73e984..b8b6b0bc6951 100644
> > --- a/drivers/iommu/iommu.c
> > +++ b/drivers/iommu/iommu.c
> > @@ -1025,7 +1025,7 @@ static size_t iommu_pgsize(struct iommu_domain
> > *domain, pgsize = (1UL << (pgsize_idx + 1)) - 1;
> >
> >       /* throw away page sizes not supported by the hardware */
> > -     pgsize &= domain->ops->pgsize_bitmap;
> > +     pgsize &= domain->pgsize_bitmap;
> >
> >       /* make sure we're still sane */
> >       BUG_ON(!pgsize);
> > @@ -1046,11 +1046,11 @@ int iommu_map(struct iommu_domain *domain, unsigned
> > long iova, int ret = 0;
> >
> >       if (unlikely(domain->ops->map == NULL ||
> > -                  domain->ops->pgsize_bitmap == 0UL))
> > +                  domain->pgsize_bitmap == 0UL))
> >               return -ENODEV;
> >
> >       /* find out the minimum page size supported */
> > -     min_pagesz = 1 << __ffs(domain->ops->pgsize_bitmap);
> > +     min_pagesz = 1 << __ffs(domain->pgsize_bitmap);
> >
> >       /*
> >        * both the virtual address and the physical one, as well as
> > @@ -1096,11 +1096,11 @@ size_t iommu_unmap(struct iommu_domain *domain,
> > unsigned long iova, size_t size) unsigned int min_pagesz;
> >
> >       if (unlikely(domain->ops->unmap == NULL ||
> > -                  domain->ops->pgsize_bitmap == 0UL))
> > +                  domain->pgsize_bitmap == 0UL))
> >               return -ENODEV;
> >
> >       /* find out the minimum page size supported */
> > -     min_pagesz = 1 << __ffs(domain->ops->pgsize_bitmap);
> > +     min_pagesz = 1 << __ffs(domain->pgsize_bitmap);
> >
> >       /*
> >        * The virtual address, as well as the size of the mapping, must be
> > @@ -1146,10 +1146,10 @@ size_t default_iommu_map_sg(struct iommu_domain
> > *domain, unsigned long iova, unsigned int i, min_pagesz;
> >       int ret;
> >
> > -     if (unlikely(domain->ops->pgsize_bitmap == 0UL))
> > +     if (unlikely(domain->pgsize_bitmap == 0UL))
> >               return 0;
> >
> > -     min_pagesz = 1 << __ffs(domain->ops->pgsize_bitmap);
> > +     min_pagesz = 1 << __ffs(domain->pgsize_bitmap);
> >
> >       for_each_sg(sg, s, nents, i) {
> >               phys_addr_t phys = page_to_phys(sg_page(s)) + s->offset;
> > @@ -1230,7 +1230,7 @@ int iommu_domain_get_attr(struct iommu_domain *domain,
> > break;
> >       case DOMAIN_ATTR_PAGING:
> >               paging  = data;
> > -             *paging = (domain->ops->pgsize_bitmap != 0UL);
> > +             *paging = (domain->pgsize_bitmap != 0UL);
> >               break;
> >       case DOMAIN_ATTR_WINDOWS:
> >               count = data;
> > diff --git a/drivers/iommu/ipmmu-vmsa.c b/drivers/iommu/ipmmu-vmsa.c
> > index 748693192c20..7e6c6a7afd81 100644
> > --- a/drivers/iommu/ipmmu-vmsa.c
> > +++ b/drivers/iommu/ipmmu-vmsa.c
> > @@ -872,6 +872,7 @@ static int ipmmu_domain_init(struct iommu_domain
> > *io_domain)
> >
> >       io_domain->priv = domain;
> >       domain->io_domain = io_domain;
> > +     domain->pgsize_bitmap = SZ_2M | SZ_64K | SZ_4K;
> >
> >       return 0;
> >  }
> > @@ -1131,7 +1132,6 @@ static const struct iommu_ops ipmmu_ops = {
> >       .iova_to_phys = ipmmu_iova_to_phys,
> >       .add_device = ipmmu_add_device,
> >       .remove_device = ipmmu_remove_device,
> > -     .pgsize_bitmap = SZ_2M | SZ_64K | SZ_4K,
> >  };
> >
> >  /*
> > ---------------------------------------------------------------------------
> > -- diff --git a/drivers/iommu/msm_iommu.c b/drivers/iommu/msm_iommu.c index
> > e1b05379ca0e..8b623dce8161 100644
> > --- a/drivers/iommu/msm_iommu.c
> > +++ b/drivers/iommu/msm_iommu.c
> > @@ -230,6 +230,8 @@ static int msm_iommu_domain_init(struct iommu_domain
> > *domain) domain->geometry.aperture_end   = (1ULL << 32) - 1;
> >       domain->geometry.force_aperture = true;
> >
> > +     domain->pgsize_bitmap = MSM_IOMMU_PGSIZES;
> > +
> >       return 0;
> >
> >  fail_nomem:
> > @@ -682,7 +684,6 @@ static const struct iommu_ops msm_iommu_ops = {
> >       .unmap = msm_iommu_unmap,
> >       .map_sg = default_iommu_map_sg,
> >       .iova_to_phys = msm_iommu_iova_to_phys,
> > -     .pgsize_bitmap = MSM_IOMMU_PGSIZES,
> >  };
> >
> >  static int __init get_tex_class(int icp, int ocp, int mt, int nos)
> > diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
> > index bbb7dcef02d3..bc4054967f18 100644
> > --- a/drivers/iommu/omap-iommu.c
> > +++ b/drivers/iommu/omap-iommu.c
> > @@ -1250,6 +1250,8 @@ static int omap_iommu_domain_init(struct iommu_domain
> > *domain) domain->geometry.aperture_end   = (1ULL << 32) - 1;
> >       domain->geometry.force_aperture = true;
> >
> > +     domain->pgsize_bitmap = OMAP_IOMMU_PGSIZES;
> > +
> >       return 0;
> >
> >  fail_nomem:
> > @@ -1368,7 +1370,6 @@ static const struct iommu_ops omap_iommu_ops = {
> >       .iova_to_phys   = omap_iommu_iova_to_phys,
> >       .add_device     = omap_iommu_add_device,
> >       .remove_device  = omap_iommu_remove_device,
> > -     .pgsize_bitmap  = OMAP_IOMMU_PGSIZES,
> >  };
> >
> >  static int __init omap_iommu_init(void)
> > diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c
> > index 6a8b1ec4a48a..5ab63e51e1c0 100644
> > --- a/drivers/iommu/rockchip-iommu.c
> > +++ b/drivers/iommu/rockchip-iommu.c
> > @@ -828,6 +828,7 @@ static int rk_iommu_domain_init(struct iommu_domain
> > *domain) INIT_LIST_HEAD(&rk_domain->iommus);
> >
> >       domain->priv = rk_domain;
> > +     domain->pgsize_bitmap = RK_IOMMU_PGSIZE_BITMAP;
> >
> >       return 0;
> >  err_dt:
> > @@ -961,7 +962,6 @@ static const struct iommu_ops rk_iommu_ops = {
> >       .add_device = rk_iommu_add_device,
> >       .remove_device = rk_iommu_remove_device,
> >       .iova_to_phys = rk_iommu_iova_to_phys,
> > -     .pgsize_bitmap = RK_IOMMU_PGSIZE_BITMAP,
> >  };
> >
> >  static int rk_iommu_probe(struct platform_device *pdev)
> > diff --git a/drivers/iommu/shmobile-iommu.c b/drivers/iommu/shmobile-iommu.c
> > index f1b00774e4de..552bde09a69b 100644
> > --- a/drivers/iommu/shmobile-iommu.c
> > +++ b/drivers/iommu/shmobile-iommu.c
> > @@ -101,6 +101,7 @@ static int shmobile_iommu_domain_init(struct
> > iommu_domain *domain) spin_lock_init(&sh_domain->attached_list_lock);
> >       INIT_LIST_HEAD(&sh_domain->attached_list);
> >       domain->priv = sh_domain;
> > +     domain->pgsize_bitmap = SZ_1M | SZ_64K | SZ_4K;
> >       return 0;
> >  }
> >
> > @@ -364,7 +365,6 @@ static const struct iommu_ops shmobile_iommu_ops = {
> >       .map_sg = default_iommu_map_sg,
> >       .iova_to_phys = shmobile_iommu_iova_to_phys,
> >       .add_device = shmobile_iommu_add_device,
> > -     .pgsize_bitmap = SZ_1M | SZ_64K | SZ_4K,
> >  };
> >
> >  int ipmmu_iommu_init(struct shmobile_ipmmu *ipmmu)
> > diff --git a/drivers/iommu/tegra-gart.c b/drivers/iommu/tegra-gart.c
> > index f722a0c466cf..6404aba9667a 100644
> > --- a/drivers/iommu/tegra-gart.c
> > +++ b/drivers/iommu/tegra-gart.c
> > @@ -218,6 +218,7 @@ out:
> >
> >  static int gart_iommu_domain_init(struct iommu_domain *domain)
> >  {
> > +     domain->pgsize_bitmap = GART_IOMMU_PGSIZES;
> >       return 0;
> >  }
> >
> > @@ -317,7 +318,6 @@ static const struct iommu_ops gart_iommu_ops = {
> >       .map            = gart_iommu_map,
> >       .unmap          = gart_iommu_unmap,
> >       .iova_to_phys   = gart_iommu_iova_to_phys,
> > -     .pgsize_bitmap  = GART_IOMMU_PGSIZES,
> >  };
> >
> >  static int tegra_gart_suspend(struct device *dev)
> > diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
> > index 6e134c7c227f..a423ed9a19da 100644
> > --- a/drivers/iommu/tegra-smmu.c
> > +++ b/drivers/iommu/tegra-smmu.c
> > @@ -265,6 +265,7 @@ static int tegra_smmu_domain_init(struct iommu_domain
> > *domain) pd[i] = 0;
> >
> >       domain->priv = as;
> > +     domain->pgsize_bitmap = SZ_4K;
> >
> >       return 0;
> >  }
> > @@ -643,8 +644,6 @@ static const struct iommu_ops tegra_smmu_ops = {
> >       .unmap = tegra_smmu_unmap,
> >       .map_sg = default_iommu_map_sg,
> >       .iova_to_phys = tegra_smmu_iova_to_phys,
> > -
> > -     .pgsize_bitmap = SZ_4K,
> >  };
> >
> >  static void tegra_smmu_ahb_enable(void)
> > diff --git a/drivers/vfio/vfio_iommu_type1.c
> > b/drivers/vfio/vfio_iommu_type1.c index 4a9d666f1e91..3bb72499e4e1 100644
> > --- a/drivers/vfio/vfio_iommu_type1.c
> > +++ b/drivers/vfio/vfio_iommu_type1.c
> > @@ -386,7 +386,7 @@ static unsigned long vfio_pgsize_bitmap(struct
> > vfio_iommu *iommu)
> >
> >       mutex_lock(&iommu->lock);
> >       list_for_each_entry(domain, &iommu->domain_list, next)
> > -             bitmap &= domain->domain->ops->pgsize_bitmap;
> > +             bitmap &= domain->domain->pgsize_bitmap;
> >       mutex_unlock(&iommu->lock);
> >
> >       return bitmap;
> > diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> > index 38daa453f2e5..ffc023e24b78 100644
> > --- a/include/linux/iommu.h
> > +++ b/include/linux/iommu.h
> > @@ -53,6 +53,7 @@ struct iommu_domain_geometry {
> >
> >  struct iommu_domain {
> >       const struct iommu_ops *ops;
> > +     unsigned long pgsize_bitmap;    /* Bitmap of supported page sizes */
> >       void *priv;
> >       iommu_fault_handler_t handler;
> >       void *handler_token;
> > @@ -108,7 +109,6 @@ enum iommu_attr {
> >   * @domain_get_attr: Query domain attributes
> >   * @domain_set_attr: Change domain attributes
> >   * @of_xlate: add OF master IDs to iommu grouping
> > - * @pgsize_bitmap: bitmap of supported page sizes
> >   * @priv: per-instance data private to the iommu driver
> >   */
> >  struct iommu_ops {
> > @@ -144,9 +144,6 @@ struct iommu_ops {
> >  #ifdef CONFIG_OF_IOMMU
> >       int (*of_xlate)(struct device *dev, struct of_phandle_args *args);
> >  #endif
> > -
> > -     unsigned long pgsize_bitmap;
> > -     void *priv;
> >  };
> >
> >  #define IOMMU_GROUP_NOTIFY_ADD_DEVICE                1 /* Device added */
> 
> --
> Regards,
> 
> Laurent Pinchart
> 
> 
>