diff options
Diffstat (limited to 'drivers/iommu/iommufd/device.c')
| -rw-r--r-- | drivers/iommu/iommufd/device.c | 1194 |
1 files changed, 1194 insertions, 0 deletions
diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c new file mode 100644 index 0000000000..ce78c36715 --- /dev/null +++ b/drivers/iommu/iommufd/device.c @@ -0,0 +1,1194 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2021-2022, NVIDIA CORPORATION & AFFILIATES + */ +#include <linux/iommufd.h> +#include <linux/slab.h> +#include <linux/iommu.h> +#include <uapi/linux/iommufd.h> +#include "../iommu-priv.h" + +#include "io_pagetable.h" +#include "iommufd_private.h" + +static bool allow_unsafe_interrupts; +module_param(allow_unsafe_interrupts, bool, S_IRUGO | S_IWUSR); +MODULE_PARM_DESC( + allow_unsafe_interrupts, + "Allow IOMMUFD to bind to devices even if the platform cannot isolate " + "the MSI interrupt window. Enabling this is a security weakness."); + +static void iommufd_group_release(struct kref *kref) +{ + struct iommufd_group *igroup = + container_of(kref, struct iommufd_group, ref); + + WARN_ON(igroup->hwpt || !list_empty(&igroup->device_list)); + + xa_cmpxchg(&igroup->ictx->groups, iommu_group_id(igroup->group), igroup, + NULL, GFP_KERNEL); + iommu_group_put(igroup->group); + mutex_destroy(&igroup->lock); + kfree(igroup); +} + +static void iommufd_put_group(struct iommufd_group *group) +{ + kref_put(&group->ref, iommufd_group_release); +} + +static bool iommufd_group_try_get(struct iommufd_group *igroup, + struct iommu_group *group) +{ + if (!igroup) + return false; + /* + * group ID's cannot be re-used until the group is put back which does + * not happen if we could get an igroup pointer under the xa_lock. + */ + if (WARN_ON(igroup->group != group)) + return false; + return kref_get_unless_zero(&igroup->ref); +} + +/* + * iommufd needs to store some more data for each iommu_group, we keep a + * parallel xarray indexed by iommu_group id to hold this instead of putting it + * in the core structure. To keep things simple the iommufd_group memory is + * unique within the iommufd_ctx. This makes it easy to check there are no + * memory leaks. + */ +static struct iommufd_group *iommufd_get_group(struct iommufd_ctx *ictx, + struct device *dev) +{ + struct iommufd_group *new_igroup; + struct iommufd_group *cur_igroup; + struct iommufd_group *igroup; + struct iommu_group *group; + unsigned int id; + + group = iommu_group_get(dev); + if (!group) + return ERR_PTR(-ENODEV); + + id = iommu_group_id(group); + + xa_lock(&ictx->groups); + igroup = xa_load(&ictx->groups, id); + if (iommufd_group_try_get(igroup, group)) { + xa_unlock(&ictx->groups); + iommu_group_put(group); + return igroup; + } + xa_unlock(&ictx->groups); + + new_igroup = kzalloc(sizeof(*new_igroup), GFP_KERNEL); + if (!new_igroup) { + iommu_group_put(group); + return ERR_PTR(-ENOMEM); + } + + kref_init(&new_igroup->ref); + mutex_init(&new_igroup->lock); + INIT_LIST_HEAD(&new_igroup->device_list); + new_igroup->sw_msi_start = PHYS_ADDR_MAX; + /* group reference moves into new_igroup */ + new_igroup->group = group; + + /* + * The ictx is not additionally refcounted here becase all objects using + * an igroup must put it before their destroy completes. + */ + new_igroup->ictx = ictx; + + /* + * We dropped the lock so igroup is invalid. NULL is a safe and likely + * value to assume for the xa_cmpxchg algorithm. + */ + cur_igroup = NULL; + xa_lock(&ictx->groups); + while (true) { + igroup = __xa_cmpxchg(&ictx->groups, id, cur_igroup, new_igroup, + GFP_KERNEL); + if (xa_is_err(igroup)) { + xa_unlock(&ictx->groups); + iommufd_put_group(new_igroup); + return ERR_PTR(xa_err(igroup)); + } + + /* new_group was successfully installed */ + if (cur_igroup == igroup) { + xa_unlock(&ictx->groups); + return new_igroup; + } + + /* Check again if the current group is any good */ + if (iommufd_group_try_get(igroup, group)) { + xa_unlock(&ictx->groups); + iommufd_put_group(new_igroup); + return igroup; + } + cur_igroup = igroup; + } +} + +void iommufd_device_destroy(struct iommufd_object *obj) +{ + struct iommufd_device *idev = + container_of(obj, struct iommufd_device, obj); + + iommu_device_release_dma_owner(idev->dev); + iommufd_put_group(idev->igroup); + if (!iommufd_selftest_is_mock_dev(idev->dev)) + iommufd_ctx_put(idev->ictx); +} + +/** + * iommufd_device_bind - Bind a physical device to an iommu fd + * @ictx: iommufd file descriptor + * @dev: Pointer to a physical device struct + * @id: Output ID number to return to userspace for this device + * + * A successful bind establishes an ownership over the device and returns + * struct iommufd_device pointer, otherwise returns error pointer. + * + * A driver using this API must set driver_managed_dma and must not touch + * the device until this routine succeeds and establishes ownership. + * + * Binding a PCI device places the entire RID under iommufd control. + * + * The caller must undo this with iommufd_device_unbind() + */ +struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx, + struct device *dev, u32 *id) +{ + struct iommufd_device *idev; + struct iommufd_group *igroup; + int rc; + + /* + * iommufd always sets IOMMU_CACHE because we offer no way for userspace + * to restore cache coherency. + */ + if (!device_iommu_capable(dev, IOMMU_CAP_CACHE_COHERENCY)) + return ERR_PTR(-EINVAL); + + igroup = iommufd_get_group(ictx, dev); + if (IS_ERR(igroup)) + return ERR_CAST(igroup); + + /* + * For historical compat with VFIO the insecure interrupt path is + * allowed if the module parameter is set. Secure/Isolated means that a + * MemWr operation from the device (eg a simple DMA) cannot trigger an + * interrupt outside this iommufd context. + */ + if (!iommufd_selftest_is_mock_dev(dev) && + !iommu_group_has_isolated_msi(igroup->group)) { + if (!allow_unsafe_interrupts) { + rc = -EPERM; + goto out_group_put; + } + + dev_warn( + dev, + "MSI interrupts are not secure, they cannot be isolated by the platform. " + "Check that platform features like interrupt remapping are enabled. " + "Use the \"allow_unsafe_interrupts\" module parameter to override\n"); + } + + rc = iommu_device_claim_dma_owner(dev, ictx); + if (rc) + goto out_group_put; + + idev = iommufd_object_alloc(ictx, idev, IOMMUFD_OBJ_DEVICE); + if (IS_ERR(idev)) { + rc = PTR_ERR(idev); + goto out_release_owner; + } + idev->ictx = ictx; + if (!iommufd_selftest_is_mock_dev(dev)) + iommufd_ctx_get(ictx); + idev->dev = dev; + idev->enforce_cache_coherency = + device_iommu_capable(dev, IOMMU_CAP_ENFORCE_CACHE_COHERENCY); + /* The calling driver is a user until iommufd_device_unbind() */ + refcount_inc(&idev->obj.users); + /* igroup refcount moves into iommufd_device */ + idev->igroup = igroup; + + /* + * If the caller fails after this success it must call + * iommufd_unbind_device() which is safe since we hold this refcount. + * This also means the device is a leaf in the graph and no other object + * can take a reference on it. + */ + iommufd_object_finalize(ictx, &idev->obj); + *id = idev->obj.id; + return idev; + +out_release_owner: + iommu_device_release_dma_owner(dev); +out_group_put: + iommufd_put_group(igroup); + return ERR_PTR(rc); +} +EXPORT_SYMBOL_NS_GPL(iommufd_device_bind, IOMMUFD); + +/** + * iommufd_ctx_has_group - True if any device within the group is bound + * to the ictx + * @ictx: iommufd file descriptor + * @group: Pointer to a physical iommu_group struct + * + * True if any device within the group has been bound to this ictx, ex. via + * iommufd_device_bind(), therefore implying ictx ownership of the group. + */ +bool iommufd_ctx_has_group(struct iommufd_ctx *ictx, struct iommu_group *group) +{ + struct iommufd_object *obj; + unsigned long index; + + if (!ictx || !group) + return false; + + xa_lock(&ictx->objects); + xa_for_each(&ictx->objects, index, obj) { + if (obj->type == IOMMUFD_OBJ_DEVICE && + container_of(obj, struct iommufd_device, obj) + ->igroup->group == group) { + xa_unlock(&ictx->objects); + return true; + } + } + xa_unlock(&ictx->objects); + return false; +} +EXPORT_SYMBOL_NS_GPL(iommufd_ctx_has_group, IOMMUFD); + +/** + * iommufd_device_unbind - Undo iommufd_device_bind() + * @idev: Device returned by iommufd_device_bind() + * + * Release the device from iommufd control. The DMA ownership will return back + * to unowned with DMA controlled by the DMA API. This invalidates the + * iommufd_device pointer, other APIs that consume it must not be called + * concurrently. + */ +void iommufd_device_unbind(struct iommufd_device *idev) +{ + iommufd_object_destroy_user(idev->ictx, &idev->obj); +} +EXPORT_SYMBOL_NS_GPL(iommufd_device_unbind, IOMMUFD); + +struct iommufd_ctx *iommufd_device_to_ictx(struct iommufd_device *idev) +{ + return idev->ictx; +} +EXPORT_SYMBOL_NS_GPL(iommufd_device_to_ictx, IOMMUFD); + +u32 iommufd_device_to_id(struct iommufd_device *idev) +{ + return idev->obj.id; +} +EXPORT_SYMBOL_NS_GPL(iommufd_device_to_id, IOMMUFD); + +static int iommufd_group_setup_msi(struct iommufd_group *igroup, + struct iommufd_hw_pagetable *hwpt) +{ + phys_addr_t sw_msi_start = igroup->sw_msi_start; + int rc; + + /* + * If the IOMMU driver gives a IOMMU_RESV_SW_MSI then it is asking us to + * call iommu_get_msi_cookie() on its behalf. This is necessary to setup + * the MSI window so iommu_dma_prepare_msi() can install pages into our + * domain after request_irq(). If it is not done interrupts will not + * work on this domain. + * + * FIXME: This is conceptually broken for iommufd since we want to allow + * userspace to change the domains, eg switch from an identity IOAS to a + * DMA IOAS. There is currently no way to create a MSI window that + * matches what the IRQ layer actually expects in a newly created + * domain. + */ + if (sw_msi_start != PHYS_ADDR_MAX && !hwpt->msi_cookie) { + rc = iommu_get_msi_cookie(hwpt->domain, sw_msi_start); + if (rc) + return rc; + + /* + * iommu_get_msi_cookie() can only be called once per domain, + * it returns -EBUSY on later calls. + */ + hwpt->msi_cookie = true; + } + return 0; +} + +int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable *hwpt, + struct iommufd_device *idev) +{ + int rc; + + mutex_lock(&idev->igroup->lock); + + if (idev->igroup->hwpt != NULL && idev->igroup->hwpt != hwpt) { + rc = -EINVAL; + goto err_unlock; + } + + /* Try to upgrade the domain we have */ + if (idev->enforce_cache_coherency) { + rc = iommufd_hw_pagetable_enforce_cc(hwpt); + if (rc) + goto err_unlock; + } + + rc = iopt_table_enforce_dev_resv_regions(&hwpt->ioas->iopt, idev->dev, + &idev->igroup->sw_msi_start); + if (rc) + goto err_unlock; + + /* + * Only attach to the group once for the first device that is in the + * group. All the other devices will follow this attachment. The user + * should attach every device individually to the hwpt as the per-device + * reserved regions are only updated during individual device + * attachment. + */ + if (list_empty(&idev->igroup->device_list)) { + rc = iommufd_group_setup_msi(idev->igroup, hwpt); + if (rc) + goto err_unresv; + + rc = iommu_attach_group(hwpt->domain, idev->igroup->group); + if (rc) + goto err_unresv; + idev->igroup->hwpt = hwpt; + } + refcount_inc(&hwpt->obj.users); + list_add_tail(&idev->group_item, &idev->igroup->device_list); + mutex_unlock(&idev->igroup->lock); + return 0; +err_unresv: + iopt_remove_reserved_iova(&hwpt->ioas->iopt, idev->dev); +err_unlock: + mutex_unlock(&idev->igroup->lock); + return rc; +} + +struct iommufd_hw_pagetable * +iommufd_hw_pagetable_detach(struct iommufd_device *idev) +{ + struct iommufd_hw_pagetable *hwpt = idev->igroup->hwpt; + + mutex_lock(&idev->igroup->lock); + list_del(&idev->group_item); + if (list_empty(&idev->igroup->device_list)) { + iommu_detach_group(hwpt->domain, idev->igroup->group); + idev->igroup->hwpt = NULL; + } + iopt_remove_reserved_iova(&hwpt->ioas->iopt, idev->dev); + mutex_unlock(&idev->igroup->lock); + + /* Caller must destroy hwpt */ + return hwpt; +} + +static struct iommufd_hw_pagetable * +iommufd_device_do_attach(struct iommufd_device *idev, + struct iommufd_hw_pagetable *hwpt) +{ + int rc; + + rc = iommufd_hw_pagetable_attach(hwpt, idev); + if (rc) + return ERR_PTR(rc); + return NULL; +} + +static struct iommufd_hw_pagetable * +iommufd_device_do_replace(struct iommufd_device *idev, + struct iommufd_hw_pagetable *hwpt) +{ + struct iommufd_group *igroup = idev->igroup; + struct iommufd_hw_pagetable *old_hwpt; + unsigned int num_devices = 0; + struct iommufd_device *cur; + int rc; + + mutex_lock(&idev->igroup->lock); + + if (igroup->hwpt == NULL) { + rc = -EINVAL; + goto err_unlock; + } + + if (hwpt == igroup->hwpt) { + mutex_unlock(&idev->igroup->lock); + return NULL; + } + + /* Try to upgrade the domain we have */ + list_for_each_entry(cur, &igroup->device_list, group_item) { + num_devices++; + if (cur->enforce_cache_coherency) { + rc = iommufd_hw_pagetable_enforce_cc(hwpt); + if (rc) + goto err_unlock; + } + } + + old_hwpt = igroup->hwpt; + if (hwpt->ioas != old_hwpt->ioas) { + list_for_each_entry(cur, &igroup->device_list, group_item) { + rc = iopt_table_enforce_dev_resv_regions( + &hwpt->ioas->iopt, cur->dev, NULL); + if (rc) + goto err_unresv; + } + } + + rc = iommufd_group_setup_msi(idev->igroup, hwpt); + if (rc) + goto err_unresv; + + rc = iommu_group_replace_domain(igroup->group, hwpt->domain); + if (rc) + goto err_unresv; + + if (hwpt->ioas != old_hwpt->ioas) { + list_for_each_entry(cur, &igroup->device_list, group_item) + iopt_remove_reserved_iova(&old_hwpt->ioas->iopt, + cur->dev); + } + + igroup->hwpt = hwpt; + + /* + * Move the refcounts held by the device_list to the new hwpt. Retain a + * refcount for this thread as the caller will free it. + */ + refcount_add(num_devices, &hwpt->obj.users); + if (num_devices > 1) + WARN_ON(refcount_sub_and_test(num_devices - 1, + &old_hwpt->obj.users)); + mutex_unlock(&idev->igroup->lock); + + /* Caller must destroy old_hwpt */ + return old_hwpt; +err_unresv: + list_for_each_entry(cur, &igroup->device_list, group_item) + iopt_remove_reserved_iova(&hwpt->ioas->iopt, cur->dev); +err_unlock: + mutex_unlock(&idev->igroup->lock); + return ERR_PTR(rc); +} + +typedef struct iommufd_hw_pagetable *(*attach_fn)( + struct iommufd_device *idev, struct iommufd_hw_pagetable *hwpt); + +/* + * When automatically managing the domains we search for a compatible domain in + * the iopt and if one is found use it, otherwise create a new domain. + * Automatic domain selection will never pick a manually created domain. + */ +static struct iommufd_hw_pagetable * +iommufd_device_auto_get_domain(struct iommufd_device *idev, + struct iommufd_ioas *ioas, u32 *pt_id, + attach_fn do_attach) +{ + /* + * iommufd_hw_pagetable_attach() is called by + * iommufd_hw_pagetable_alloc() in immediate attachment mode, same as + * iommufd_device_do_attach(). So if we are in this mode then we prefer + * to use the immediate_attach path as it supports drivers that can't + * directly allocate a domain. + */ + bool immediate_attach = do_attach == iommufd_device_do_attach; + struct iommufd_hw_pagetable *destroy_hwpt; + struct iommufd_hw_pagetable *hwpt; + + /* + * There is no differentiation when domains are allocated, so any domain + * that is willing to attach to the device is interchangeable with any + * other. + */ + mutex_lock(&ioas->mutex); + list_for_each_entry(hwpt, &ioas->hwpt_list, hwpt_item) { + if (!hwpt->auto_domain) + continue; + + if (!iommufd_lock_obj(&hwpt->obj)) + continue; + destroy_hwpt = (*do_attach)(idev, hwpt); + if (IS_ERR(destroy_hwpt)) { + iommufd_put_object(&hwpt->obj); + /* + * -EINVAL means the domain is incompatible with the + * device. Other error codes should propagate to + * userspace as failure. Success means the domain is + * attached. + */ + if (PTR_ERR(destroy_hwpt) == -EINVAL) + continue; + goto out_unlock; + } + *pt_id = hwpt->obj.id; + iommufd_put_object(&hwpt->obj); + goto out_unlock; + } + + hwpt = iommufd_hw_pagetable_alloc(idev->ictx, ioas, idev, + immediate_attach); + if (IS_ERR(hwpt)) { + destroy_hwpt = ERR_CAST(hwpt); + goto out_unlock; + } + + if (!immediate_attach) { + destroy_hwpt = (*do_attach)(idev, hwpt); + if (IS_ERR(destroy_hwpt)) + goto out_abort; + } else { + destroy_hwpt = NULL; + } + + hwpt->auto_domain = true; + *pt_id = hwpt->obj.id; + + iommufd_object_finalize(idev->ictx, &hwpt->obj); + mutex_unlock(&ioas->mutex); + return destroy_hwpt; + +out_abort: + iommufd_object_abort_and_destroy(idev->ictx, &hwpt->obj); +out_unlock: + mutex_unlock(&ioas->mutex); + return destroy_hwpt; +} + +static int iommufd_device_change_pt(struct iommufd_device *idev, u32 *pt_id, + attach_fn do_attach) +{ + struct iommufd_hw_pagetable *destroy_hwpt; + struct iommufd_object *pt_obj; + + pt_obj = iommufd_get_object(idev->ictx, *pt_id, IOMMUFD_OBJ_ANY); + if (IS_ERR(pt_obj)) + return PTR_ERR(pt_obj); + + switch (pt_obj->type) { + case IOMMUFD_OBJ_HW_PAGETABLE: { + struct iommufd_hw_pagetable *hwpt = + container_of(pt_obj, struct iommufd_hw_pagetable, obj); + + destroy_hwpt = (*do_attach)(idev, hwpt); + if (IS_ERR(destroy_hwpt)) + goto out_put_pt_obj; + break; + } + case IOMMUFD_OBJ_IOAS: { + struct iommufd_ioas *ioas = + container_of(pt_obj, struct iommufd_ioas, obj); + + destroy_hwpt = iommufd_device_auto_get_domain(idev, ioas, pt_id, + do_attach); + if (IS_ERR(destroy_hwpt)) + goto out_put_pt_obj; + break; + } + default: + destroy_hwpt = ERR_PTR(-EINVAL); + goto out_put_pt_obj; + } + iommufd_put_object(pt_obj); + + /* This destruction has to be after we unlock everything */ + if (destroy_hwpt) + iommufd_hw_pagetable_put(idev->ictx, destroy_hwpt); + return 0; + +out_put_pt_obj: + iommufd_put_object(pt_obj); + return PTR_ERR(destroy_hwpt); +} + +/** + * iommufd_device_attach - Connect a device to an iommu_domain + * @idev: device to attach + * @pt_id: Input a IOMMUFD_OBJ_IOAS, or IOMMUFD_OBJ_HW_PAGETABLE + * Output the IOMMUFD_OBJ_HW_PAGETABLE ID + * + * This connects the device to an iommu_domain, either automatically or manually + * selected. Once this completes the device could do DMA. + * + * The caller should return the resulting pt_id back to userspace. + * This function is undone by calling iommufd_device_detach(). + */ +int iommufd_device_attach(struct iommufd_device *idev, u32 *pt_id) +{ + int rc; + + rc = iommufd_device_change_pt(idev, pt_id, &iommufd_device_do_attach); + if (rc) + return rc; + + /* + * Pairs with iommufd_device_detach() - catches caller bugs attempting + * to destroy a device with an attachment. + */ + refcount_inc(&idev->obj.users); + return 0; +} +EXPORT_SYMBOL_NS_GPL(iommufd_device_attach, IOMMUFD); + +/** + * iommufd_device_replace - Change the device's iommu_domain + * @idev: device to change + * @pt_id: Input a IOMMUFD_OBJ_IOAS, or IOMMUFD_OBJ_HW_PAGETABLE + * Output the IOMMUFD_OBJ_HW_PAGETABLE ID + * + * This is the same as:: + * + * iommufd_device_detach(); + * iommufd_device_attach(); + * + * If it fails then no change is made to the attachment. The iommu driver may + * implement this so there is no disruption in translation. This can only be + * called if iommufd_device_attach() has already succeeded. + */ +int iommufd_device_replace(struct iommufd_device *idev, u32 *pt_id) +{ + return iommufd_device_change_pt(idev, pt_id, + &iommufd_device_do_replace); +} +EXPORT_SYMBOL_NS_GPL(iommufd_device_replace, IOMMUFD); + +/** + * iommufd_device_detach - Disconnect a device to an iommu_domain + * @idev: device to detach + * + * Undo iommufd_device_attach(). This disconnects the idev from the previously + * attached pt_id. The device returns back to a blocked DMA translation. + */ +void iommufd_device_detach(struct iommufd_device *idev) +{ + struct iommufd_hw_pagetable *hwpt; + + hwpt = iommufd_hw_pagetable_detach(idev); + iommufd_hw_pagetable_put(idev->ictx, hwpt); + refcount_dec(&idev->obj.users); +} +EXPORT_SYMBOL_NS_GPL(iommufd_device_detach, IOMMUFD); + +/* + * On success, it will refcount_inc() at a valid new_ioas and refcount_dec() at + * a valid cur_ioas (access->ioas). A caller passing in a valid new_ioas should + * call iommufd_put_object() if it does an iommufd_get_object() for a new_ioas. + */ +static int iommufd_access_change_ioas(struct iommufd_access *access, + struct iommufd_ioas *new_ioas) +{ + u32 iopt_access_list_id = access->iopt_access_list_id; + struct iommufd_ioas *cur_ioas = access->ioas; + int rc; + + lockdep_assert_held(&access->ioas_lock); + + /* We are racing with a concurrent detach, bail */ + if (cur_ioas != access->ioas_unpin) + return -EBUSY; + + if (cur_ioas == new_ioas) + return 0; + + /* + * Set ioas to NULL to block any further iommufd_access_pin_pages(). + * iommufd_access_unpin_pages() can continue using access->ioas_unpin. + */ + access->ioas = NULL; + + if (new_ioas) { + rc = iopt_add_access(&new_ioas->iopt, access); + if (rc) { + access->ioas = cur_ioas; + return rc; + } + refcount_inc(&new_ioas->obj.users); + } + + if (cur_ioas) { + if (access->ops->unmap) { + mutex_unlock(&access->ioas_lock); + access->ops->unmap(access->data, 0, ULONG_MAX); + mutex_lock(&access->ioas_lock); + } + iopt_remove_access(&cur_ioas->iopt, access, iopt_access_list_id); + refcount_dec(&cur_ioas->obj.users); + } + + access->ioas = new_ioas; + access->ioas_unpin = new_ioas; + + return 0; +} + +static int iommufd_access_change_ioas_id(struct iommufd_access *access, u32 id) +{ + struct iommufd_ioas *ioas = iommufd_get_ioas(access->ictx, id); + int rc; + + if (IS_ERR(ioas)) + return PTR_ERR(ioas); + rc = iommufd_access_change_ioas(access, ioas); + iommufd_put_object(&ioas->obj); + return rc; +} + +void iommufd_access_destroy_object(struct iommufd_object *obj) +{ + struct iommufd_access *access = + container_of(obj, struct iommufd_access, obj); + + mutex_lock(&access->ioas_lock); + if (access->ioas) + WARN_ON(iommufd_access_change_ioas(access, NULL)); + mutex_unlock(&access->ioas_lock); + iommufd_ctx_put(access->ictx); +} + +/** + * iommufd_access_create - Create an iommufd_access + * @ictx: iommufd file descriptor + * @ops: Driver's ops to associate with the access + * @data: Opaque data to pass into ops functions + * @id: Output ID number to return to userspace for this access + * + * An iommufd_access allows a driver to read/write to the IOAS without using + * DMA. The underlying CPU memory can be accessed using the + * iommufd_access_pin_pages() or iommufd_access_rw() functions. + * + * The provided ops are required to use iommufd_access_pin_pages(). + */ +struct iommufd_access * +iommufd_access_create(struct iommufd_ctx *ictx, + const struct iommufd_access_ops *ops, void *data, u32 *id) +{ + struct iommufd_access *access; + + /* + * There is no uAPI for the access object, but to keep things symmetric + * use the object infrastructure anyhow. + */ + access = iommufd_object_alloc(ictx, access, IOMMUFD_OBJ_ACCESS); + if (IS_ERR(access)) + return access; + + access->data = data; + access->ops = ops; + + if (ops->needs_pin_pages) + access->iova_alignment = PAGE_SIZE; + else + access->iova_alignment = 1; + + /* The calling driver is a user until iommufd_access_destroy() */ + refcount_inc(&access->obj.users); + access->ictx = ictx; + iommufd_ctx_get(ictx); + iommufd_object_finalize(ictx, &access->obj); + *id = access->obj.id; + mutex_init(&access->ioas_lock); + return access; +} +EXPORT_SYMBOL_NS_GPL(iommufd_access_create, IOMMUFD); + +/** + * iommufd_access_destroy - Destroy an iommufd_access + * @access: The access to destroy + * + * The caller must stop using the access before destroying it. + */ +void iommufd_access_destroy(struct iommufd_access *access) +{ + iommufd_object_destroy_user(access->ictx, &access->obj); +} +EXPORT_SYMBOL_NS_GPL(iommufd_access_destroy, IOMMUFD); + +void iommufd_access_detach(struct iommufd_access *access) +{ + mutex_lock(&access->ioas_lock); + if (WARN_ON(!access->ioas)) { + mutex_unlock(&access->ioas_lock); + return; + } + WARN_ON(iommufd_access_change_ioas(access, NULL)); + mutex_unlock(&access->ioas_lock); +} +EXPORT_SYMBOL_NS_GPL(iommufd_access_detach, IOMMUFD); + +int iommufd_access_attach(struct iommufd_access *access, u32 ioas_id) +{ + int rc; + + mutex_lock(&access->ioas_lock); + if (WARN_ON(access->ioas)) { + mutex_unlock(&access->ioas_lock); + return -EINVAL; + } + + rc = iommufd_access_change_ioas_id(access, ioas_id); + mutex_unlock(&access->ioas_lock); + return rc; +} +EXPORT_SYMBOL_NS_GPL(iommufd_access_attach, IOMMUFD); + +int iommufd_access_replace(struct iommufd_access *access, u32 ioas_id) +{ + int rc; + + mutex_lock(&access->ioas_lock); + if (!access->ioas) { + mutex_unlock(&access->ioas_lock); + return -ENOENT; + } + rc = iommufd_access_change_ioas_id(access, ioas_id); + mutex_unlock(&access->ioas_lock); + return rc; +} +EXPORT_SYMBOL_NS_GPL(iommufd_access_replace, IOMMUFD); + +/** + * iommufd_access_notify_unmap - Notify users of an iopt to stop using it + * @iopt: iopt to work on + * @iova: Starting iova in the iopt + * @length: Number of bytes + * + * After this function returns there should be no users attached to the pages + * linked to this iopt that intersect with iova,length. Anyone that has attached + * a user through iopt_access_pages() needs to detach it through + * iommufd_access_unpin_pages() before this function returns. + * + * iommufd_access_destroy() will wait for any outstanding unmap callback to + * complete. Once iommufd_access_destroy() no unmap ops are running or will + * run in the future. Due to this a driver must not create locking that prevents + * unmap to complete while iommufd_access_destroy() is running. + */ +void iommufd_access_notify_unmap(struct io_pagetable *iopt, unsigned long iova, + unsigned long length) +{ + struct iommufd_ioas *ioas = + container_of(iopt, struct iommufd_ioas, iopt); + struct iommufd_access *access; + unsigned long index; + + xa_lock(&ioas->iopt.access_list); + xa_for_each(&ioas->iopt.access_list, index, access) { + if (!iommufd_lock_obj(&access->obj)) + continue; + xa_unlock(&ioas->iopt.access_list); + + access->ops->unmap(access->data, iova, length); + + iommufd_put_object(&access->obj); + xa_lock(&ioas->iopt.access_list); + } + xa_unlock(&ioas->iopt.access_list); +} + +/** + * iommufd_access_unpin_pages() - Undo iommufd_access_pin_pages + * @access: IOAS access to act on + * @iova: Starting IOVA + * @length: Number of bytes to access + * + * Return the struct page's. The caller must stop accessing them before calling + * this. The iova/length must exactly match the one provided to access_pages. + */ +void iommufd_access_unpin_pages(struct iommufd_access *access, + unsigned long iova, unsigned long length) +{ + struct iopt_area_contig_iter iter; + struct io_pagetable *iopt; + unsigned long last_iova; + struct iopt_area *area; + + if (WARN_ON(!length) || + WARN_ON(check_add_overflow(iova, length - 1, &last_iova))) + return; + + mutex_lock(&access->ioas_lock); + /* + * The driver must be doing something wrong if it calls this before an + * iommufd_access_attach() or after an iommufd_access_detach(). + */ + if (WARN_ON(!access->ioas_unpin)) { + mutex_unlock(&access->ioas_lock); + return; + } + iopt = &access->ioas_unpin->iopt; + + down_read(&iopt->iova_rwsem); + iopt_for_each_contig_area(&iter, area, iopt, iova, last_iova) + iopt_area_remove_access( + area, iopt_area_iova_to_index(area, iter.cur_iova), + iopt_area_iova_to_index( + area, + min(last_iova, iopt_area_last_iova(area)))); + WARN_ON(!iopt_area_contig_done(&iter)); + up_read(&iopt->iova_rwsem); + mutex_unlock(&access->ioas_lock); +} +EXPORT_SYMBOL_NS_GPL(iommufd_access_unpin_pages, IOMMUFD); + +static bool iopt_area_contig_is_aligned(struct iopt_area_contig_iter *iter) +{ + if (iopt_area_start_byte(iter->area, iter->cur_iova) % PAGE_SIZE) + return false; + + if (!iopt_area_contig_done(iter) && + (iopt_area_start_byte(iter->area, iopt_area_last_iova(iter->area)) % + PAGE_SIZE) != (PAGE_SIZE - 1)) + return false; + return true; +} + +static bool check_area_prot(struct iopt_area *area, unsigned int flags) +{ + if (flags & IOMMUFD_ACCESS_RW_WRITE) + return area->iommu_prot & IOMMU_WRITE; + return area->iommu_prot & IOMMU_READ; +} + +/** + * iommufd_access_pin_pages() - Return a list of pages under the iova + * @access: IOAS access to act on + * @iova: Starting IOVA + * @length: Number of bytes to access + * @out_pages: Output page list + * @flags: IOPMMUFD_ACCESS_RW_* flags + * + * Reads @length bytes starting at iova and returns the struct page * pointers. + * These can be kmap'd by the caller for CPU access. + * + * The caller must perform iommufd_access_unpin_pages() when done to balance + * this. + * + * This API always requires a page aligned iova. This happens naturally if the + * ioas alignment is >= PAGE_SIZE and the iova is PAGE_SIZE aligned. However + * smaller alignments have corner cases where this API can fail on otherwise + * aligned iova. + */ +int iommufd_access_pin_pages(struct iommufd_access *access, unsigned long iova, + unsigned long length, struct page **out_pages, + unsigned int flags) +{ + struct iopt_area_contig_iter iter; + struct io_pagetable *iopt; + unsigned long last_iova; + struct iopt_area *area; + int rc; + + /* Driver's ops don't support pin_pages */ + if (IS_ENABLED(CONFIG_IOMMUFD_TEST) && + WARN_ON(access->iova_alignment != PAGE_SIZE || !access->ops->unmap)) + return -EINVAL; + + if (!length) + return -EINVAL; + if (check_add_overflow(iova, length - 1, &last_iova)) + return -EOVERFLOW; + + mutex_lock(&access->ioas_lock); + if (!access->ioas) { + mutex_unlock(&access->ioas_lock); + return -ENOENT; + } + iopt = &access->ioas->iopt; + + down_read(&iopt->iova_rwsem); + iopt_for_each_contig_area(&iter, area, iopt, iova, last_iova) { + unsigned long last = min(last_iova, iopt_area_last_iova(area)); + unsigned long last_index = iopt_area_iova_to_index(area, last); + unsigned long index = + iopt_area_iova_to_index(area, iter.cur_iova); + + if (area->prevent_access || + !iopt_area_contig_is_aligned(&iter)) { + rc = -EINVAL; + goto err_remove; + } + + if (!check_area_prot(area, flags)) { + rc = -EPERM; + goto err_remove; + } + + rc = iopt_area_add_access(area, index, last_index, out_pages, + flags); + if (rc) + goto err_remove; + out_pages += last_index - index + 1; + } + if (!iopt_area_contig_done(&iter)) { + rc = -ENOENT; + goto err_remove; + } + + up_read(&iopt->iova_rwsem); + mutex_unlock(&access->ioas_lock); + return 0; + +err_remove: + if (iova < iter.cur_iova) { + last_iova = iter.cur_iova - 1; + iopt_for_each_contig_area(&iter, area, iopt, iova, last_iova) + iopt_area_remove_access( + area, + iopt_area_iova_to_index(area, iter.cur_iova), + iopt_area_iova_to_index( + area, min(last_iova, + iopt_area_last_iova(area)))); + } + up_read(&iopt->iova_rwsem); + mutex_unlock(&access->ioas_lock); + return rc; +} +EXPORT_SYMBOL_NS_GPL(iommufd_access_pin_pages, IOMMUFD); + +/** + * iommufd_access_rw - Read or write data under the iova + * @access: IOAS access to act on + * @iova: Starting IOVA + * @data: Kernel buffer to copy to/from + * @length: Number of bytes to access + * @flags: IOMMUFD_ACCESS_RW_* flags + * + * Copy kernel to/from data into the range given by IOVA/length. If flags + * indicates IOMMUFD_ACCESS_RW_KTHREAD then a large copy can be optimized + * by changing it into copy_to/from_user(). + */ +int iommufd_access_rw(struct iommufd_access *access, unsigned long iova, + void *data, size_t length, unsigned int flags) +{ + struct iopt_area_contig_iter iter; + struct io_pagetable *iopt; + struct iopt_area *area; + unsigned long last_iova; + int rc; + + if (!length) + return -EINVAL; + if (check_add_overflow(iova, length - 1, &last_iova)) + return -EOVERFLOW; + + mutex_lock(&access->ioas_lock); + if (!access->ioas) { + mutex_unlock(&access->ioas_lock); + return -ENOENT; + } + iopt = &access->ioas->iopt; + + down_read(&iopt->iova_rwsem); + iopt_for_each_contig_area(&iter, area, iopt, iova, last_iova) { + unsigned long last = min(last_iova, iopt_area_last_iova(area)); + unsigned long bytes = (last - iter.cur_iova) + 1; + + if (area->prevent_access) { + rc = -EINVAL; + goto err_out; + } + + if (!check_area_prot(area, flags)) { + rc = -EPERM; + goto err_out; + } + + rc = iopt_pages_rw_access( + area->pages, iopt_area_start_byte(area, iter.cur_iova), + data, bytes, flags); + if (rc) + goto err_out; + data += bytes; + } + if (!iopt_area_contig_done(&iter)) + rc = -ENOENT; +err_out: + up_read(&iopt->iova_rwsem); + mutex_unlock(&access->ioas_lock); + return rc; +} +EXPORT_SYMBOL_NS_GPL(iommufd_access_rw, IOMMUFD); + +int iommufd_get_hw_info(struct iommufd_ucmd *ucmd) +{ + struct iommu_hw_info *cmd = ucmd->cmd; + void __user *user_ptr = u64_to_user_ptr(cmd->data_uptr); + const struct iommu_ops *ops; + struct iommufd_device *idev; + unsigned int data_len; + unsigned int copy_len; + void *data; + int rc; + + if (cmd->flags || cmd->__reserved) + return -EOPNOTSUPP; + + idev = iommufd_get_device(ucmd, cmd->dev_id); + if (IS_ERR(idev)) + return PTR_ERR(idev); + + ops = dev_iommu_ops(idev->dev); + if (ops->hw_info) { + data = ops->hw_info(idev->dev, &data_len, &cmd->out_data_type); + if (IS_ERR(data)) { + rc = PTR_ERR(data); + goto out_put; + } + + /* + * drivers that have hw_info callback should have a unique + * iommu_hw_info_type. + */ + if (WARN_ON_ONCE(cmd->out_data_type == + IOMMU_HW_INFO_TYPE_NONE)) { + rc = -ENODEV; + goto out_free; + } + } else { + cmd->out_data_type = IOMMU_HW_INFO_TYPE_NONE; + data_len = 0; + data = NULL; + } + + copy_len = min(cmd->data_len, data_len); + if (copy_to_user(user_ptr, data, copy_len)) { + rc = -EFAULT; + goto out_free; + } + + /* + * Zero the trailing bytes if the user buffer is bigger than the + * data size kernel actually has. + */ + if (copy_len < cmd->data_len) { + if (clear_user(user_ptr + copy_len, cmd->data_len - copy_len)) { + rc = -EFAULT; + goto out_free; + } + } + + /* + * We return the length the kernel supports so userspace may know what + * the kernel capability is. It could be larger than the input buffer. + */ + cmd->data_len = data_len; + + rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd)); +out_free: + kfree(data); +out_put: + iommufd_put_object(&idev->obj); + return rc; +} |