RE: [PATCH RFC 02/19] iommufd: Dirty tracking for io_pagetable

Shameerali Kolothum Thodi
2022-08-29T10:02:10Z

> -----Original Message-----
> From: Joao Martins [mailto:joao.m.martins@oracle.com]
> Sent: 28 April 2022 22:09
> To: iommu@lists.linux-foundation.org
> Cc: Joao Martins <joao.m.martins@oracle.com>; Joerg Roedel
> <joro@8bytes.org>; Suravee Suthikulpanit
> <suravee.suthikulpanit@amd.com>; Will Deacon <will@kernel.org>; Robin
> Murphy <robin.murphy@arm.com>; Jean-Philippe Brucker
> <jean-philippe@linaro.org>; zhukeqian <zhukeqian1@huawei.com>;
> Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>;
> David Woodhouse <dwmw2@infradead.org>; Lu Baolu
> <baolu.lu@linux.intel.com>; Jason Gunthorpe <jgg@nvidia.com>; Nicolin
> Chen <nicolinc@nvidia.com>; Yishai Hadas <yishaih@nvidia.com>; Kevin Tian
> <kevin.tian@intel.com>; Eric Auger <eric.auger@redhat.com>; Yi Liu
> <yi.l.liu@intel.com>; Alex Williamson <alex.williamson@redhat.com>;
> Cornelia Huck <cohuck@redhat.com>; kvm@vger.kernel.org
> Subject: [PATCH RFC 02/19] iommufd: Dirty tracking for io_pagetable
>
> Add an io_pagetable kernel API to toggle dirty tracking:
>
> * iopt_set_dirty_tracking(iopt, [domain], state)
>
> It receives either NULL (which means all domains) or an
> iommu_domain. The intended caller of this is via the hw_pagetable
> object that is created on device attach, which passes an
> iommu_domain. For now, the all-domains is left for vfio-compat.
>
> The hw protection domain dirty control is favored over the IOVA-range
> alternative. For the latter, it iterates over all IOVA areas and calls
> iommu domain op to enable/disable for the range.
>
> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> ---
> drivers/iommu/iommufd/io_pagetable.c | 71
> +++++++++++++++++++++++++
> drivers/iommu/iommufd/iommufd_private.h | 3 ++
> 2 files changed, 74 insertions(+)
>
> diff --git a/drivers/iommu/iommufd/io_pagetable.c
> b/drivers/iommu/iommufd/io_pagetable.c
> index f9f3b06946bf..f4609ef369e0 100644
> --- a/drivers/iommu/iommufd/io_pagetable.c
> +++ b/drivers/iommu/iommufd/io_pagetable.c
> @@ -276,6 +276,77 @@ int iopt_map_user_pages(struct io_pagetable *iopt,
> unsigned long *iova,
> return 0;
> }
>
> +static int __set_dirty_tracking_range_locked(struct iommu_domain
> *domain,
> + struct io_pagetable *iopt,
> + bool enable)
> +{
> + const struct iommu_domain_ops *ops = domain->ops;
> + struct iommu_iotlb_gather gather;
> + struct iopt_area *area;
> + int ret = -EOPNOTSUPP;
> + unsigned long iova;
> + size_t size;
> +
> + iommu_iotlb_gather_init(&gather);
> +
> + for (area = iopt_area_iter_first(iopt, 0, ULONG_MAX); area;
> + area = iopt_area_iter_next(area, 0, ULONG_MAX)) {
> + iova = iopt_area_iova(area);
> + size = iopt_area_last_iova(area) - iova;

size = iopt_area_last_iova(area) - iova + 1; ?

Thanks,
Shameer
> +
> + if (ops->set_dirty_tracking_range) {
> + ret = ops->set_dirty_tracking_range(domain, iova,
> + size, &gather,
> + enable);
> + if (ret < 0)
> + break;
> + }
> + }
> +
> + iommu_iotlb_sync(domain, &gather);
> +
> + return ret;
> +}
> +
> +static int iommu_set_dirty_tracking(struct iommu_domain *domain,
> + struct io_pagetable *iopt, bool enable)
> +{
> + const struct iommu_domain_ops *ops = domain->ops;
> + int ret = -EOPNOTSUPP;
> +
> + if (ops->set_dirty_tracking)
> + ret = ops->set_dirty_tracking(domain, enable);
> + else if (ops->set_dirty_tracking_range)
> + ret = __set_dirty_tracking_range_locked(domain, iopt,
> + enable);
> +
> + return ret;
> +}
> +
> +int iopt_set_dirty_tracking(struct io_pagetable *iopt,
> + struct iommu_domain *domain, bool enable)
> +{
> + struct iommu_domain *dom;
> + unsigned long index;
> + int ret = -EOPNOTSUPP;
> +
> + down_write(&iopt->iova_rwsem);
> + if (!domain) {
> + down_write(&iopt->domains_rwsem);
> + xa_for_each(&iopt->domains, index, dom) {
> + ret = iommu_set_dirty_tracking(dom, iopt, enable);
> + if (ret < 0)
> + break;
> + }
> + up_write(&iopt->domains_rwsem);
> + } else {
> + ret = iommu_set_dirty_tracking(domain, iopt, enable);
> + }
> +
> + up_write(&iopt->iova_rwsem);
> + return ret;
> +}
> +
> struct iopt_pages *iopt_get_pages(struct io_pagetable *iopt, unsigned long
> iova,
> unsigned long *start_byte,
> unsigned long length)
> diff --git a/drivers/iommu/iommufd/iommufd_private.h
> b/drivers/iommu/iommufd/iommufd_private.h
> index f55654278ac4..d00ef3b785c5 100644
> --- a/drivers/iommu/iommufd/iommufd_private.h
> +++ b/drivers/iommu/iommufd/iommufd_private.h
> @@ -49,6 +49,9 @@ int iopt_unmap_iova(struct io_pagetable *iopt,
> unsigned long iova,
> unsigned long length);
> int iopt_unmap_all(struct io_pagetable *iopt);
>
> +int iopt_set_dirty_tracking(struct io_pagetable *iopt,
> + struct iommu_domain *domain, bool enable);
> +
> int iopt_access_pages(struct io_pagetable *iopt, unsigned long iova,
> unsigned long npages, struct page **out_pages, bool write);
> void iopt_unaccess_pages(struct io_pagetable *iopt, unsigned long iova,
> --
> 2.17.2