Hi Jean,

> -----Original Message-----
> From: Jean-Philippe Brucker <[email protected]>
> Sent: Monday, March 23, 2020 3:30 PM
> To: Bharat Bhushan <[email protected]>
> Cc: [email protected]; [email protected]; [email protected];
> [email protected]; [email protected];
> [email protected]
> Subject: [EXT] Re: [PATCH RFC] iommu/virtio: Use page size bitmap supported by
> endpoint
> 
> External Email
> 
> ----------------------------------------------------------------------
> Hi Bharat,
> 
> Please add the IOMMU list on your next posting

[email protected] is there, any other mailing list we need to 
add?

> 
> On Mon, Mar 23, 2020 at 02:11:08PM +0530, Bharat Bhushan wrote:
> > Different endpoint can support different page size, probe endpoint if
> > it supports specific page size otherwise use global page sizes.
> >
> > Signed-off-by: Bharat Bhushan <[email protected]>
> > ---
> >  drivers/iommu/virtio-iommu.c      | 24 ++++++++++++++++++++----
> >  include/uapi/linux/virtio_iommu.h |  6 ++++++
> >  2 files changed, 26 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/iommu/virtio-iommu.c
> > b/drivers/iommu/virtio-iommu.c index cce329d71fba..e69347ca4ee6 100644
> > --- a/drivers/iommu/virtio-iommu.c
> > +++ b/drivers/iommu/virtio-iommu.c
> > @@ -78,6 +78,7 @@ struct viommu_endpoint {
> >     struct viommu_dev               *viommu;
> >     struct viommu_domain            *vdomain;
> >     struct list_head                resv_regions;
> > +   u64                             pgsize_bitmap;
> >  };
> >
> >  struct viommu_request {
> > @@ -415,6 +416,14 @@ static int viommu_replay_mappings(struct
> viommu_domain *vdomain)
> >     return ret;
> >  }
> >
> > +static int viommu_set_pgsize_bitmap(struct viommu_endpoint *vdev,
> > +                               struct virtio_iommu_probe_pgsize_mask *mask)
> > +
> > +{
> > +   vdev->pgsize_bitmap = mask->pgsize_bitmap;
> 
> We need to read this through le64_to_cpu(). Also check that the length of the 
> field
> provided by the device is >= sizeof(mask) (like
> viommu_add_resv_mem() does)

Will take care of all the comments in next verions

Thank
-Bharat

> 
> > +   return 0;
> > +}
> > +
> >  static int viommu_add_resv_mem(struct viommu_endpoint *vdev,
> >                            struct virtio_iommu_probe_resv_mem *mem,
> >                            size_t len)
> > @@ -494,11 +503,13 @@ static int viommu_probe_endpoint(struct viommu_dev
> *viommu, struct device *dev)
> >     while (type != VIRTIO_IOMMU_PROBE_T_NONE &&
> >            cur < viommu->probe_size) {
> >             len = le16_to_cpu(prop->length) + sizeof(*prop);
> > -
> >             switch (type) {
> >             case VIRTIO_IOMMU_PROBE_T_RESV_MEM:
> >                     ret = viommu_add_resv_mem(vdev, (void *)prop, len);
> >                     break;
> > +           case VIRTIO_IOMMU_PROBE_T_PAGE_SIZE_MASK:
> > +                   ret = viommu_set_pgsize_bitmap(vdev, (void *)prop);
> > +                   break;
> >             default:
> >                     dev_err(dev, "unknown viommu prop 0x%x\n", type);
> >             }
> > @@ -607,16 +618,21 @@ static struct iommu_domain
> *viommu_domain_alloc(unsigned type)
> >     return &vdomain->domain;
> >  }
> >
> > -static int viommu_domain_finalise(struct viommu_dev *viommu,
> > +static int viommu_domain_finalise(struct viommu_endpoint *vdev,
> >                               struct iommu_domain *domain)
> >  {
> >     int ret;
> >     struct viommu_domain *vdomain = to_viommu_domain(domain);
> > +   struct viommu_dev *viommu = vdev->viommu;
> >
> >     vdomain->viommu         = viommu;
> >     vdomain->map_flags      = viommu->map_flags;
> >
> > -   domain->pgsize_bitmap   = viommu->pgsize_bitmap;
> > +   if (vdev->pgsize_bitmap)
> > +           domain->pgsize_bitmap = vdev->pgsize_bitmap;
> > +   else
> > +           domain->pgsize_bitmap   = viommu->pgsize_bitmap;
> > +
> 
> nit: it could be nicer to initialize vdev->pgsize_bitmap in add_device(), 
> override it
> in probe_endpoint(), and just copy it here.
> 
> >     domain->geometry        = viommu->geometry;
> >
> >     ret = ida_alloc_range(&viommu->domain_ids, viommu->first_domain, @@
> > -657,7 +673,7 @@ static int viommu_attach_dev(struct iommu_domain
> *domain, struct device *dev)
> >              * Properly initialize the domain now that we know which viommu
> >              * owns it.
> >              */
> > -           ret = viommu_domain_finalise(vdev->viommu, domain);
> > +           ret = viommu_domain_finalise(vdev, domain);
> 
> Attaching additional endpoints with different masks to the domain should 
> return
> an error
> 
> >     } else if (vdomain->viommu != vdev->viommu) {
> >             dev_err(dev, "cannot attach to foreign vIOMMU\n");
> >             ret = -EXDEV;
> > diff --git a/include/uapi/linux/virtio_iommu.h
> > b/include/uapi/linux/virtio_iommu.h
> > index 237e36a280cb..aff3db0ef54b 100644
> > --- a/include/uapi/linux/virtio_iommu.h
> > +++ b/include/uapi/linux/virtio_iommu.h
> > @@ -111,6 +111,7 @@ struct virtio_iommu_req_unmap {
> >
> >  #define VIRTIO_IOMMU_PROBE_T_NONE          0
> >  #define VIRTIO_IOMMU_PROBE_T_RESV_MEM              1
> > +#define VIRTIO_IOMMU_PROBE_T_PAGE_SIZE_MASK        2
> >
> >  #define VIRTIO_IOMMU_PROBE_T_MASK          0xfff
> >
> > @@ -119,6 +120,11 @@ struct virtio_iommu_probe_property {
> >     __le16                                  length;
> >  };
> >
> > +struct virtio_iommu_probe_pgsize_mask {
> > +   struct virtio_iommu_probe_property      head;
> 
> Compilers will introduce 4 bytes of padding here, to align the next field.
> We need to make them explicit by adding a 4-bytes 'reserved' field.
> 
> > +   uint64_t                                pgsize_bitmap;
> 
> __le64
> 
> Thanks,
> Jean
> 
> > +};
> > +
> >  #define VIRTIO_IOMMU_RESV_MEM_T_RESERVED   0
> >  #define VIRTIO_IOMMU_RESV_MEM_T_MSI                1
> >
> > --
> > 2.17.1
> >
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