RE: [RFC v2 14/22] vfio/pci: add iommu_context notifier for pasid bind/unbind

["Liu, Yi L" <yi.l.liu@intel.com>]

> From: David Gibson
> Sent: Tuesday, November 5, 2019 12:02 AM
> To: Liu, Yi L <yi.l.liu@intel.com>
> Subject: Re: [RFC v2 14/22] vfio/pci: add iommu_context notifier for pasid
> bind/unbind
> 
> On Thu, Oct 24, 2019 at 08:34:35AM -0400, Liu Yi L wrote:
> > This patch adds notifier for pasid bind/unbind. VFIO registers this
> > notifier to listen to the dual-stage translation (a.k.a. nested
> > translation) configuration changes and propagate to host. Thus vIOMMU
> > is able to set its translation structures to host.
> >
> > Cc: Kevin Tian <kevin.tian@intel.com>
> > Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
> > Cc: Peter Xu <peterx@redhat.com>
> > Cc: Eric Auger <eric.auger@redhat.com>
> > Cc: Yi Sun <yi.y.sun@linux.intel.com>
> > Cc: David Gibson <david@gibson.dropbear.id.au>
> > Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
> > ---
> >  hw/vfio/pci.c            | 39 +++++++++++++++++++++++++++++++++++++++
> >  include/hw/iommu/iommu.h | 11 +++++++++++
> >  2 files changed, 50 insertions(+)
> >
> > diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> > index 8721ff6..012b8ed 100644
> > --- a/hw/vfio/pci.c
> > +++ b/hw/vfio/pci.c
> > @@ -2767,6 +2767,41 @@ static void
> vfio_iommu_pasid_free_notify(IOMMUCTXNotifier *n,
> >      pasid_req->free_result = ret;
> >  }
> >
> > +static void vfio_iommu_pasid_bind_notify(IOMMUCTXNotifier *n,
> > +                                         IOMMUCTXEventData *event_data)
> > +{
> > +#ifdef __linux__
> 
> Is hw/vfio/pci.c even built on non-linux hosts?

I'm not quite sure. It's based a comment from RFC v1. I think it could somehow
prevent compiling issue when doing code porting. So I added it. If it's impossible
to build on non-linux hosts per your experience, I can remove it to make things
simple.

> > +    VFIOIOMMUContext *giommu_ctx = container_of(n, VFIOIOMMUContext, n);
> > +    VFIOContainer *container = giommu_ctx->container;
> > +    IOMMUCTXPASIDBindData *pasid_bind =
> > +                              (IOMMUCTXPASIDBindData *) event_data->data;
> > +    struct vfio_iommu_type1_bind *bind;
> > +    struct iommu_gpasid_bind_data *bind_data;
> > +    unsigned long argsz;
> > +
> > +    argsz = sizeof(*bind) + sizeof(*bind_data);
> > +    bind = g_malloc0(argsz);
> > +    bind->argsz = argsz;
> > +    bind->bind_type = VFIO_IOMMU_BIND_GUEST_PASID;
> > +    bind_data = (struct iommu_gpasid_bind_data *) &bind->data;
> > +    *bind_data = *pasid_bind->data;
> > +
> > +    if (pasid_bind->flag & IOMMU_CTX_BIND_PASID) {
> > +        if (ioctl(container->fd, VFIO_IOMMU_BIND, bind) != 0) {
> > +            error_report("%s: pasid (%llu:%llu) bind failed: %d", __func__,
> > +                         bind_data->gpasid, bind_data->hpasid, -errno);
> > +        }
> > +    } else if (pasid_bind->flag & IOMMU_CTX_UNBIND_PASID) {
> > +        if (ioctl(container->fd, VFIO_IOMMU_UNBIND, bind) != 0) {
> > +            error_report("%s: pasid (%llu:%llu) unbind failed: %d", __func__,
> > +                         bind_data->gpasid, bind_data->hpasid, -errno);
> > +        }
> > +    }
> > +
> > +    g_free(bind);
> > +#endif
> > +}
> > +
> >  static void vfio_realize(PCIDevice *pdev, Error **errp)
> >  {
> >      VFIOPCIDevice *vdev = PCI_VFIO(pdev);
> > @@ -3079,6 +3114,10 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
> >                                           iommu_context,
> >                                           vfio_iommu_pasid_free_notify,
> >                                           IOMMU_CTX_EVENT_PASID_FREE);
> > +        vfio_register_iommu_ctx_notifier(vdev,
> > +                                         iommu_context,
> > +                                         vfio_iommu_pasid_bind_notify,
> > +                                         IOMMU_CTX_EVENT_PASID_BIND);
> >      }
> >
> >      return;
> > diff --git a/include/hw/iommu/iommu.h b/include/hw/iommu/iommu.h
> > index 4352afd..4f21aa1 100644
> > --- a/include/hw/iommu/iommu.h
> > +++ b/include/hw/iommu/iommu.h
> > @@ -33,6 +33,7 @@ typedef struct IOMMUContext IOMMUContext;
> >  enum IOMMUCTXEvent {
> >      IOMMU_CTX_EVENT_PASID_ALLOC,
> >      IOMMU_CTX_EVENT_PASID_FREE,
> > +    IOMMU_CTX_EVENT_PASID_BIND,
> >      IOMMU_CTX_EVENT_NUM,
> >  };
> >  typedef enum IOMMUCTXEvent IOMMUCTXEvent;
> > @@ -50,6 +51,16 @@ union IOMMUCTXPASIDReqDesc {
> >  };
> >  typedef union IOMMUCTXPASIDReqDesc IOMMUCTXPASIDReqDesc;
> >
> > +struct IOMMUCTXPASIDBindData {
> > +#define IOMMU_CTX_BIND_PASID   (1 << 0)
> > +#define IOMMU_CTX_UNBIND_PASID (1 << 1)
> > +    uint32_t flag;
> > +#ifdef __linux__
> > +    struct iommu_gpasid_bind_data *data;
> 
> Embedding a linux specific structure in the notification message seems
> dubious to me.

Just similar as your above comment in this thread. If we don't want to add
it there, then here it is also unnecessary.

@Eric, do you think it is still necessary to add the __linux__ marco here?

Thanks,
Yi Liu