From 2a3dab19a0a6c1823645764188776f271de1b3cf Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Tue, 29 Nov 2022 16:31:50 -0400 Subject: vfio-iommufd: Allow iommufd to be used in place of a container fd This makes VFIO_GROUP_SET_CONTAINER accept both a vfio container FD and an iommufd. In iommufd mode an IOAS will exist after the SET_CONTAINER, but it will not be attached to any groups. For VFIO this means that the VFIO_GROUP_GET_STATUS and VFIO_GROUP_FLAGS_VIABLE works subtly differently. With the container FD the iommu_group_claim_dma_owner() is done during SET_CONTAINER but for IOMMUFD this is done during VFIO_GROUP_GET_DEVICE_FD. Meaning that VFIO_GROUP_FLAGS_VIABLE could be set but GET_DEVICE_FD will fail due to viability. As GET_DEVICE_FD can fail for many reasons already this is not expected to be a meaningful difference. Reorganize the tests for if the group has an assigned container or iommu into a vfio_group_has_iommu() function and consolidate all the duplicated WARN_ON's etc related to this. Call container functions only if a container is actually present on the group. Link: https://lore.kernel.org/r/5-v4-42cd2eb0e3eb+335a-vfio_iommufd_jgg@nvidia.com Reviewed-by: Kevin Tian Reviewed-by: Alex Williamson Tested-by: Alex Williamson Tested-by: Nicolin Chen Tested-by: Yi Liu Tested-by: Lixiao Yang Tested-by: Matthew Rosato Tested-by: Yu He Signed-off-by: Jason Gunthorpe --- drivers/vfio/Kconfig | 1 + drivers/vfio/container.c | 7 ++-- drivers/vfio/vfio.h | 2 ++ drivers/vfio/vfio_main.c | 88 ++++++++++++++++++++++++++++++++++++++++-------- 4 files changed, 82 insertions(+), 16 deletions(-) diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig index 86c381ceb9a1..1118d322eec9 100644 --- a/drivers/vfio/Kconfig +++ b/drivers/vfio/Kconfig @@ -2,6 +2,7 @@ menuconfig VFIO tristate "VFIO Non-Privileged userspace driver framework" select IOMMU_API + depends on IOMMUFD || !IOMMUFD select VFIO_IOMMU_TYPE1 if MMU && (X86 || S390 || ARM || ARM64) select INTERVAL_TREE help diff --git a/drivers/vfio/container.c b/drivers/vfio/container.c index d97747dfb05d..8772dad68085 100644 --- a/drivers/vfio/container.c +++ b/drivers/vfio/container.c @@ -516,8 +516,11 @@ int vfio_group_use_container(struct vfio_group *group) { lockdep_assert_held(&group->group_lock); - if (!group->container || !group->container->iommu_driver || - WARN_ON(!group->container_users)) + /* + * The container fd has been assigned with VFIO_GROUP_SET_CONTAINER but + * VFIO_SET_IOMMU hasn't been done yet. + */ + if (!group->container->iommu_driver) return -EINVAL; if (group->type == VFIO_NO_IOMMU && !capable(CAP_SYS_RAWIO)) diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h index 731561258704..a9dd0615266c 100644 --- a/drivers/vfio/vfio.h +++ b/drivers/vfio/vfio.h @@ -10,6 +10,7 @@ #include #include +struct iommufd_ctx; struct iommu_group; struct vfio_device; struct vfio_container; @@ -60,6 +61,7 @@ struct vfio_group { struct kvm *kvm; struct file *opened_file; struct blocking_notifier_head notifier; + struct iommufd_ctx *iommufd; }; /* events for the backend driver notify callback */ diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c index 77d6c0ba6a83..f11157d056e6 100644 --- a/drivers/vfio/vfio_main.c +++ b/drivers/vfio/vfio_main.c @@ -35,6 +35,7 @@ #include #include #include +#include #include "vfio.h" #define DRIVER_VERSION "0.3" @@ -662,6 +663,18 @@ EXPORT_SYMBOL_GPL(vfio_unregister_group_dev); /* * VFIO Group fd, /dev/vfio/$GROUP */ +static bool vfio_group_has_iommu(struct vfio_group *group) +{ + lockdep_assert_held(&group->group_lock); + /* + * There can only be users if there is a container, and if there is a + * container there must be users. + */ + WARN_ON(!group->container != !group->container_users); + + return group->container || group->iommufd; +} + /* * VFIO_GROUP_UNSET_CONTAINER should fail if there are other users or * if there was no container to unset. Since the ioctl is called on @@ -673,15 +686,21 @@ static int vfio_group_ioctl_unset_container(struct vfio_group *group) int ret = 0; mutex_lock(&group->group_lock); - if (!group->container) { + if (!vfio_group_has_iommu(group)) { ret = -EINVAL; goto out_unlock; } - if (group->container_users != 1) { - ret = -EBUSY; - goto out_unlock; + if (group->container) { + if (group->container_users != 1) { + ret = -EBUSY; + goto out_unlock; + } + vfio_group_detach_container(group); + } + if (group->iommufd) { + iommufd_ctx_put(group->iommufd); + group->iommufd = NULL; } - vfio_group_detach_container(group); out_unlock: mutex_unlock(&group->group_lock); @@ -692,6 +711,7 @@ static int vfio_group_ioctl_set_container(struct vfio_group *group, int __user *arg) { struct vfio_container *container; + struct iommufd_ctx *iommufd; struct fd f; int ret; int fd; @@ -704,7 +724,7 @@ static int vfio_group_ioctl_set_container(struct vfio_group *group, return -EBADF; mutex_lock(&group->group_lock); - if (group->container || WARN_ON(group->container_users)) { + if (vfio_group_has_iommu(group)) { ret = -EINVAL; goto out_unlock; } @@ -714,12 +734,28 @@ static int vfio_group_ioctl_set_container(struct vfio_group *group, } container = vfio_container_from_file(f.file); - ret = -EINVAL; if (container) { ret = vfio_container_attach_group(container, group); goto out_unlock; } + iommufd = iommufd_ctx_from_file(f.file); + if (!IS_ERR(iommufd)) { + u32 ioas_id; + + ret = iommufd_vfio_compat_ioas_id(iommufd, &ioas_id); + if (ret) { + iommufd_ctx_put(group->iommufd); + goto out_unlock; + } + + group->iommufd = iommufd; + goto out_unlock; + } + + /* The FD passed is not recognized. */ + ret = -EBADFD; + out_unlock: mutex_unlock(&group->group_lock); fdput(f); @@ -749,9 +785,16 @@ static int vfio_device_first_open(struct vfio_device *device) * during close_device. */ mutex_lock(&device->group->group_lock); - ret = vfio_group_use_container(device->group); - if (ret) + if (!vfio_group_has_iommu(device->group)) { + ret = -EINVAL; goto err_module_put; + } + + if (device->group->container) { + ret = vfio_group_use_container(device->group); + if (ret) + goto err_module_put; + } device->kvm = device->group->kvm; if (device->ops->open_device) { @@ -759,13 +802,15 @@ static int vfio_device_first_open(struct vfio_device *device) if (ret) goto err_container; } - vfio_device_container_register(device); + if (device->group->container) + vfio_device_container_register(device); mutex_unlock(&device->group->group_lock); return 0; err_container: device->kvm = NULL; - vfio_group_unuse_container(device->group); + if (device->group->container) + vfio_group_unuse_container(device->group); err_module_put: mutex_unlock(&device->group->group_lock); module_put(device->dev->driver->owner); @@ -777,11 +822,13 @@ static void vfio_device_last_close(struct vfio_device *device) lockdep_assert_held(&device->dev_set->lock); mutex_lock(&device->group->group_lock); - vfio_device_container_unregister(device); + if (device->group->container) + vfio_device_container_unregister(device); if (device->ops->close_device) device->ops->close_device(device); device->kvm = NULL; - vfio_group_unuse_container(device->group); + if (device->group->container) + vfio_group_unuse_container(device->group); mutex_unlock(&device->group->group_lock); module_put(device->dev->driver->owner); } @@ -897,7 +944,14 @@ static int vfio_group_ioctl_get_status(struct vfio_group *group, return -ENODEV; } - if (group->container) + /* + * With the container FD the iommu_group_claim_dma_owner() is done + * during SET_CONTAINER but for IOMMFD this is done during + * VFIO_GROUP_GET_DEVICE_FD. Meaning that with iommufd + * VFIO_GROUP_FLAGS_VIABLE could be set but GET_DEVICE_FD will fail due + * to viability. + */ + if (vfio_group_has_iommu(group)) status.flags |= VFIO_GROUP_FLAGS_CONTAINER_SET | VFIO_GROUP_FLAGS_VIABLE; else if (!iommu_group_dma_owner_claimed(group->iommu_group)) @@ -980,6 +1034,10 @@ static int vfio_group_fops_release(struct inode *inode, struct file *filep) WARN_ON(group->notifier.head); if (group->container) vfio_group_detach_container(group); + if (group->iommufd) { + iommufd_ctx_put(group->iommufd); + group->iommufd = NULL; + } group->opened_file = NULL; mutex_unlock(&group->group_lock); return 0; @@ -1878,6 +1936,8 @@ static void __exit vfio_cleanup(void) module_init(vfio_init); module_exit(vfio_cleanup); +MODULE_IMPORT_NS(IOMMUFD); +MODULE_IMPORT_NS(IOMMUFD_VFIO); MODULE_VERSION(DRIVER_VERSION); MODULE_LICENSE("GPL v2"); MODULE_AUTHOR(DRIVER_AUTHOR); -- cgit v1.2.1