On Sat, Sep 23, 2023 at 02:24:56AM +0100, Joao Martins wrote: > Throughout IOMMU domain lifetime that wants to use dirty tracking, some > guarantees are needed such that any device attached to the iommu_domain > supports dirty tracking. > > The idea is to handle a case where IOMMU in the system are assymetric > feature-wise and thus the capability may not be supported for all devices. > The enforcement is done by adding a flag into HWPT_ALLOC namely: > > IOMMUFD_HWPT_ALLOC_ENFORCE_DIRTY > > .. Passed in HWPT_ALLOC ioctl() flags. The enforcement is done by creating > a iommu_domain via domain_alloc_user() and validating the requested flags > with what the device IOMMU supports (and failing accordingly) advertised). > Advertising the new IOMMU domain feature flag requires that the individual > iommu driver capability is supported when a future device attachment > happens. > > Link: https://lore.kernel.org/kvm/20220721142421.GB4609@xxxxxxxxxx/ > Signed-off-by: Joao Martins <joao.m.martins@xxxxxxxxxx> > --- > drivers/iommu/iommufd/hw_pagetable.c | 8 ++++++-- > include/uapi/linux/iommufd.h | 3 +++ > 2 files changed, 9 insertions(+), 2 deletions(-) > > diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c > index 26a8a818ffa3..32e259245314 100644 > --- a/drivers/iommu/iommufd/hw_pagetable.c > +++ b/drivers/iommu/iommufd/hw_pagetable.c > @@ -83,7 +83,9 @@ iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas, > > lockdep_assert_held(&ioas->mutex); > > - if ((flags & IOMMU_HWPT_ALLOC_NEST_PARENT) && !ops->domain_alloc_user) > + if ((flags & (IOMMU_HWPT_ALLOC_NEST_PARENT| > + IOMMU_HWPT_ALLOC_ENFORCE_DIRTY)) && > + !ops->domain_alloc_user) > return ERR_PTR(-EOPNOTSUPP); This seems strange, why are we testing flags here? shouldn't this just be if (flags && !ops->domain_alloc_user) return ERR_PTR(-EOPNOTSUPP); ? > hwpt = iommufd_object_alloc(ictx, hwpt, IOMMUFD_OBJ_HW_PAGETABLE); > @@ -157,7 +159,9 @@ int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd) > struct iommufd_ioas *ioas; > int rc; > > - if (cmd->flags & ~IOMMU_HWPT_ALLOC_NEST_PARENT || cmd->__reserved) > + if ((cmd->flags & > + ~(IOMMU_HWPT_ALLOC_NEST_PARENT|IOMMU_HWPT_ALLOC_ENFORCE_DIRTY)) || > + cmd->__reserved) > return -EOPNOTSUPP; Please checkpatch your stuff, and even better feed the patches to clang-format and do most of what it says. Otherwise seems like the right thing to do Jason
