From: Logan Odell <[email protected]> Collect the IO page table usage statistics from each IOMMU domain attached to a legacy VFIO container and expose that data to userspace via the new iommu-nr-pages field in fdinfo.
Introduce and implement the get_nr_pages callback for vfio-iommu-type1, that iterates over all attached domains and aggregates their nr_pages counters. Only domains whose page table is implemented by the generic_pt library account their page table memory. If any domain attached to the container does not, get_nr_pages() returns -EOPNOTSUPP and the field is omitted instead of reporting a partial count. Document the new field in Documentation/filesystems/proc.rst. Signed-off-by: Logan Odell <[email protected]> Signed-off-by: Pranjal Shrivastava <[email protected]> --- Documentation/filesystems/proc.rst | 17 +++++++++++++++++ drivers/vfio/container.c | 21 +++++++++++++++++++++ drivers/vfio/vfio.h | 2 ++ drivers/vfio/vfio_iommu_type1.c | 21 +++++++++++++++++++++ 4 files changed, 61 insertions(+) diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst index c102b62023cd..2d06c9930fcf 100644 --- a/Documentation/filesystems/proc.rst +++ b/Documentation/filesystems/proc.rst @@ -2200,6 +2200,23 @@ VFIO Device files where 'vfio-device-syspath' is the sysfs path corresponding to the VFIO device file. +VFIO Container files +~~~~~~~~~~~~~~~~~~~~ + +:: + + pos: 0 + flags: 02000002 + mnt_id: 17 + ino: 1103 + iommu-nr-pages: 11 + +where 'iommu-nr-pages' is the number of pages of memory used by the IO page +tables of all IOMMU domains attached to the container. It is omitted when no +IOMMU backend is set, or when any attached domain does not account its IO page +table memory. Currently only domains using the generic_pt page table library +account their IO page table memory. + 3.9 /proc/<pid>/map_files - Information about memory mapped files --------------------------------------------------------------------- This directory contains symbolic links which represent memory mapped files diff --git a/drivers/vfio/container.c b/drivers/vfio/container.c index 003281dbf8bc..2cb6c5373626 100644 --- a/drivers/vfio/container.c +++ b/drivers/vfio/container.c @@ -7,6 +7,7 @@ #include <linux/file.h> #include <linux/slab.h> #include <linux/fs.h> +#include <linux/seq_file.h> #include <linux/capability.h> #include <linux/iommu.h> #include <linux/miscdevice.h> @@ -384,12 +385,32 @@ static int vfio_fops_release(struct inode *inode, struct file *filep) return 0; } +#ifdef CONFIG_PROC_FS +static void vfio_fops_show_fdinfo(struct seq_file *m, struct file *filep) +{ + struct vfio_container *container = filep->private_data; + long nr_pages = -EOPNOTSUPP; + + down_read(&container->group_lock); + if (container->iommu_driver && container->iommu_driver->ops->get_nr_pages) + nr_pages = container->iommu_driver->ops->get_nr_pages(container->iommu_data); + up_read(&container->group_lock); + + /* Only report a count that covers every domain in the container */ + if (nr_pages >= 0) + seq_printf(m, "iommu-nr-pages:\t%ld\n", nr_pages); +} +#endif + static const struct file_operations vfio_fops = { .owner = THIS_MODULE, .open = vfio_fops_open, .release = vfio_fops_release, .unlocked_ioctl = vfio_fops_unl_ioctl, .compat_ioctl = compat_ptr_ioctl, +#ifdef CONFIG_PROC_FS + .show_fdinfo = vfio_fops_show_fdinfo, +#endif }; struct vfio_container *vfio_container_from_file(struct file *file) diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h index 7728bc99b63d..37e8841ad0e9 100644 --- a/drivers/vfio/vfio.h +++ b/drivers/vfio/vfio.h @@ -226,6 +226,8 @@ struct vfio_iommu_driver_ops { void *data, size_t count, bool write); struct iommu_domain *(*group_iommu_domain)(void *iommu_data, struct iommu_group *group); + /* Returns IO page table pages used, or -EOPNOTSUPP if not accounted */ + long (*get_nr_pages)(void *iommu_data); }; struct vfio_iommu_driver { diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index c8151ba54de3..fc7c1553d574 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -3249,6 +3249,26 @@ vfio_iommu_type1_group_iommu_domain(void *iommu_data, return domain; } +static long vfio_iommu_type1_get_nr_pages(void *iommu_data) +{ + struct vfio_iommu *iommu = iommu_data; + struct vfio_domain *d; + long total = 0; + + mutex_lock(&iommu->lock); + list_for_each_entry(d, &iommu->domain_list, next) { + /* Only generic_pt page tables account their pages */ + if (!d->domain->is_iommupt) { + total = -EOPNOTSUPP; + break; + } + total += atomic_long_read(&d->domain->nr_pages); + } + mutex_unlock(&iommu->lock); + + return total; +} + static const struct vfio_iommu_driver_ops vfio_iommu_driver_ops_type1 = { .name = "vfio-iommu-type1", .owner = THIS_MODULE, @@ -3263,6 +3283,7 @@ static const struct vfio_iommu_driver_ops vfio_iommu_driver_ops_type1 = { .unregister_device = vfio_iommu_type1_unregister_device, .dma_rw = vfio_iommu_type1_dma_rw, .group_iommu_domain = vfio_iommu_type1_group_iommu_domain, + .get_nr_pages = vfio_iommu_type1_get_nr_pages, }; static int __init vfio_iommu_type1_init(void) -- 2.56.0.rc1.315.gc6ed9934b7-goog
