Re: [PATCH 2/6] iommu/vt-d: Implement hw_info for iommu capability query

[Baolu Lu]

On 2023/2/13 11:09, Binbin Wu wrote:
> On 2/9/2023 12:16 PM, Yi Liu wrote:
> > From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> >
> > To support nested translation in the userspace, it should check the
> > underlying hardware information for the capabilities.
> >
> > Add intel_iommu_hw_info() to report cap_reg and ecap_reg information.
> >
> > Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> > Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>
> > Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
> > Signed-off-by: Yi Sun <yi.y.sun@xxxxxxxxxxxxxxx>
> > ---
> >   drivers/iommu/intel/iommu.c  | 19 +++++++++++++++++++
> >   drivers/iommu/intel/iommu.h  |  1 +
> >   include/uapi/linux/iommufd.h | 21 +++++++++++++++++++++
> >   3 files changed, 41 insertions(+)
> >
> > diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> > index 59df7e42fd53..929f600cc350 100644
> > --- a/drivers/iommu/intel/iommu.c
> > +++ b/drivers/iommu/intel/iommu.c
> > @@ -4760,8 +4760,26 @@ static void intel_iommu_remove_dev_pasid(struct 
> > device *dev, ioasid_t pasid)
> >       intel_pasid_tear_down_entry(iommu, dev, pasid, false);
> >   }
> > +static void *intel_iommu_hw_info(struct device *dev, u32 *length)
> > +{
> > +    struct device_domain_info *info = dev_iommu_priv_get(dev);
> > +    struct intel_iommu *iommu = info->iommu;
> > +    struct iommu_device_info_vtd *vtd;
> > +
> > +    vtd = kzalloc(sizeof(*vtd), GFP_KERNEL);
> > +    if (!vtd)
> > +        return ERR_PTR(-ENOMEM);
> > +
> > +    vtd->cap_reg = iommu->cap;
> > +    vtd->ecap_reg = iommu->ecap;
> > +    *length = sizeof(*vtd);
> > +
> > +    return vtd;
> > +}
> > +
> >   const struct iommu_ops intel_iommu_ops = {
> >       .capable        = intel_iommu_capable,
> > +    .hw_info        = intel_iommu_hw_info,
> >       .domain_alloc        = intel_iommu_domain_alloc,
> >       .probe_device        = intel_iommu_probe_device,
> >       .probe_finalize        = intel_iommu_probe_finalize,
> > @@ -4774,6 +4792,7 @@ const struct iommu_ops intel_iommu_ops = {
> >       .def_domain_type    = device_def_domain_type,
> >       .remove_dev_pasid    = intel_iommu_remove_dev_pasid,
> >       .pgsize_bitmap        = SZ_4K,
> > +    .driver_type        = IOMMU_DEVICE_DATA_INTEL_VTD,
> >   #ifdef CONFIG_INTEL_IOMMU_SVM
> >       .page_response        = intel_svm_page_response,
> >   #endif
> > diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
> > index 06e61e474856..2e70265d4ceb 100644
> > --- a/drivers/iommu/intel/iommu.h
> > +++ b/drivers/iommu/intel/iommu.h
> > @@ -22,6 +22,7 @@
> >   #include <linux/ioasid.h>
> >   #include <linux/bitfield.h>
> >   #include <linux/xarray.h>
> > +#include <uapi/linux/iommufd.h>
> >   #include <asm/cacheflush.h>
> >   #include <asm/iommu.h>
> > diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
> > index 2309edb55028..fda75c8450ee 100644
> > --- a/include/uapi/linux/iommufd.h
> > +++ b/include/uapi/linux/iommufd.h
> > @@ -347,7 +347,28 @@ struct iommu_vfio_ioas {
> >   /**
> >    * enum iommu_device_data_type - IOMMU hardware Data types
> > + * @IOMMU_DEVICE_DATA_INTEL_VTD: Intel VT-d iommu data type
> >    */
> >   enum iommu_device_data_type {
> > +    IOMMU_DEVICE_DATA_INTEL_VTD = 1,
> > +};
> > +
> > +/**
> > + * struct iommu_device_info_vtd - Intel VT-d device info
> > + *
> > + * @flags: Must be set to 0
>
> Could you add more description about the usage of flags here?

This is a Reserved 0 fields for other coming features.

Best regards,
baolu