On Fri, Mar 10, 2023 at 11:30:04AM +0800, Baolu Lu wrote: > External email: Use caution opening links or attachments > > > On 3/9/23 4:09 PM, Yi Liu wrote: > > This provides a way for userspace to probe the supported hwpt data > > types by kernel. Currently, kernel only supports IOMMU_HWPT_TYPE_DEFAULT, > > new types would be added per vendor drivers' extension. > > > > Userspace that wants to allocate hw_pagetable with user data should check > > this. While for the allocation without user data, no need for it. It is > > supported by default. > > > > Co-developed-by: Nicolin Chen <nicolinc@xxxxxxxxxx> > > Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx> > > Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx> > > --- > > drivers/iommu/iommufd/device.c | 1 + > > drivers/iommu/iommufd/hw_pagetable.c | 18 +++++++++++++++--- > > drivers/iommu/iommufd/iommufd_private.h | 2 ++ > > drivers/iommu/iommufd/main.c | 2 +- > > include/uapi/linux/iommufd.h | 8 ++++++++ > > 5 files changed, 27 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c > > index 19cd6df46c6a..0328071dcac1 100644 > > --- a/drivers/iommu/iommufd/device.c > > +++ b/drivers/iommu/iommufd/device.c > > @@ -322,6 +322,7 @@ int iommufd_device_get_hw_info(struct iommufd_ucmd *ucmd) > > > > cmd->out_data_type = ops->driver_type; > > cmd->data_len = length; > > + cmd->out_hwpt_type_bitmap = iommufd_hwpt_type_bitmaps[ops->driver_type]; > > > > rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd)); > > > > diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c > > index 67facca98de1..160712256c64 100644 > > --- a/drivers/iommu/iommufd/hw_pagetable.c > > +++ b/drivers/iommu/iommufd/hw_pagetable.c > > @@ -173,6 +173,14 @@ static const size_t iommufd_hwpt_alloc_data_size[] = { > > [IOMMU_HWPT_TYPE_DEFAULT] = 0, > > }; > > > > +/* > > + * bitmaps of supported hwpt types of by underlying iommu, indexed > > + * by ops->driver_type which is one of enum iommu_hw_info_type. > > + */ > > +const u64 iommufd_hwpt_type_bitmaps[] = { > > + [IOMMU_HW_INFO_TYPE_DEFAULT] = BIT_ULL(IOMMU_HWPT_TYPE_DEFAULT), > > +}; > > I am a bit confused here. Why do you need this array? What I read is > that you want to convert ops->driver_type to a bit position in > cmd->out_hwpt_type_bitmap. > > Am I getting it right? > > If so, why not just > cmd->out_hwpt_type_bitmap = BIT_ULL(ops->driver_type); > > ? A driver_type would be IOMMUFD_HW_INFO_TYPExx. What's inside the BIT_ULL is IOMMUFD_HWPT_TYPE_*. It seems to get a bit confusing after several rounds of renaming though. And they do seem to be a bit of duplications at the actual values, at least for now. I recall that we only had one enum for the types, yet later did a separation into driver_types and hwpt_types after a discussion regarding future PASID support? Thanks Nic