Add APIs that can be used to preserve and unpreserve a vfio cdev. Use the APIs exported by the IOMMU core to preserve/unpreserve device. The LUO token of the preserved iommufd is fetched and returned back to the caller as that can be used during restore to get the restored iommufd. Signed-off-by: Samiullah Khawaja Reviewed-by: Pranjal Shrivastava --- drivers/iommu/iommufd/device.c | 153 ++++++++++++++++++++++++ drivers/iommu/iommufd/iommufd_private.h | 3 + include/linux/iommufd.h | 33 +++++ 3 files changed, 189 insertions(+) diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c index 1b0bdf57ac8a..1e42e85af819 100644 --- a/drivers/iommu/iommufd/device.c +++ b/drivers/iommu/iommufd/device.c @@ -2,6 +2,7 @@ /* Copyright (c) 2021-2022, NVIDIA CORPORATION & AFFILIATES */ #include +#include #include #include #include @@ -686,6 +687,10 @@ int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable *hwpt, int rc; mutex_lock(&igroup->lock); + if (iommufd_device_is_preserved(idev)) { + rc = -EBUSY; + goto err_unlock; + } attach = xa_cmpxchg(&igroup->pasid_attach, pasid, NULL, XA_ZERO_ENTRY, GFP_KERNEL); @@ -869,6 +874,10 @@ iommufd_device_do_replace(struct iommufd_device *idev, ioasid_t pasid, int rc; mutex_lock(&igroup->lock); + if (iommufd_device_is_preserved(idev)) { + rc = -EBUSY; + goto err_unlock; + } attach = xa_load(&igroup->pasid_attach, pasid); if (!attach) { @@ -1749,3 +1758,147 @@ int iommufd_get_hw_info(struct iommufd_ucmd *ucmd) iommufd_put_object(ucmd->ictx, &idev->obj); return rc; } + +#ifdef CONFIG_IOMMU_LIVEUPDATE +static bool _iommufd_device_has_pasid_attachments(struct iommufd_device *idev) +{ + struct iommufd_group *igroup = idev->igroup; + unsigned long start = IOMMU_NO_PASID; + + if (xa_find_after(&igroup->pasid_attach, &start, UINT_MAX, XA_PRESENT)) + return true; + + return false; +} + +/** + * iommufd_device_preserve() - Preserve an iommufd device across live update + * @s: Live update session + * @idev: Target iommufd device + * @iommufd_tokenp: Pointer to store outgoing iommufd token + * + * Return: 0 on success, or negative error code. + */ +int iommufd_device_preserve(struct liveupdate_session *s, + struct iommufd_device *idev, + u64 *iommufd_tokenp) +{ + struct iommufd_hwpt_paging *hwpt_paging; + struct iommufd_hw_pagetable *hwpt; + struct iommufd_attach *attach; + struct iommufd_group *igroup; + int ret; + + if (!idev) + return -EINVAL; + + if (iommufd_device_is_noiommu(idev)) + return -EOPNOTSUPP; + + igroup = idev->igroup; + mutex_lock(&igroup->lock); + if (idev->liveupdate_preserved) { + ret = -EBUSY; + goto out; + } + + if (_iommufd_device_has_pasid_attachments(idev)) { + ret = -EOPNOTSUPP; + goto out; + } + + attach = xa_load(&igroup->pasid_attach, IOMMU_NO_PASID); + if (!attach) { + ret = -ENOENT; + goto out; + } + + if (!xa_load(&attach->device_array, idev->obj.id)) { + ret = -ENOENT; + goto out; + } + + hwpt = attach->hwpt; + if (!hwpt_is_paging(hwpt)) { + ret = -EOPNOTSUPP; + goto out; + } + + hwpt_paging = to_hwpt_paging(hwpt); + ret = liveupdate_get_token_outgoing(s, idev->ictx->file, iommufd_tokenp); + if (ret) + goto out; + + if (!hwpt_paging->liveupdate_preserved) { + ret = -EINVAL; + goto out; + } + + ret = iommu_preserve_device(hwpt_paging->common.domain, + idev->dev, + *iommufd_tokenp); + + if (!ret) + idev->liveupdate_preserved = true; +out: + mutex_unlock(&igroup->lock); + return ret; +} +EXPORT_SYMBOL_NS_GPL(iommufd_device_preserve, "IOMMUFD"); + +/** + * iommufd_device_unpreserve() - Unpreserve an iommufd device + * @s: Live update session + * @idev: Target iommufd device + */ +void iommufd_device_unpreserve(struct liveupdate_session *s, + struct iommufd_device *idev) +{ + struct iommufd_hwpt_paging *hwpt_paging; + struct iommufd_hw_pagetable *hwpt; + struct iommufd_attach *attach; + struct iommufd_group *igroup; + + if (!idev) + return; + + igroup = idev->igroup; + mutex_lock(&igroup->lock); + if (!idev->liveupdate_preserved) + goto out; + + attach = xa_load(&igroup->pasid_attach, IOMMU_NO_PASID); + if (!attach) { + WARN(1, "IOMMU_NO_PASID attachment not found"); + goto out; + } + + hwpt = attach->hwpt; + if (WARN(!hwpt_is_paging(hwpt), "Attached HWPT is not a paging HWPT")) + goto out; + + hwpt_paging = to_hwpt_paging(hwpt); + if (!hwpt_paging->liveupdate_preserved) { + WARN(1, "Attached domain is not preserved"); + goto out; + } + + iommu_unpreserve_device(idev->dev); + idev->liveupdate_preserved = false; +out: + mutex_unlock(&igroup->lock); +} +EXPORT_SYMBOL_NS_GPL(iommufd_device_unpreserve, "IOMMUFD"); + +/** + * iommufd_device_is_preserved() - Check if an iommufd device is preserved + * @idev: Target iommufd device + * + * Return: true if preserved, false otherwise. + */ +bool iommufd_device_is_preserved(struct iommufd_device *idev) +{ + return idev && idev->liveupdate_preserved; +} +EXPORT_SYMBOL_NS_GPL(iommufd_device_is_preserved, "IOMMUFD"); +#endif diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h index 69d902b69b82..df231d1e7d09 100644 --- a/drivers/iommu/iommufd/iommufd_private.h +++ b/drivers/iommu/iommufd/iommufd_private.h @@ -524,6 +524,9 @@ struct iommufd_device { bool enforce_cache_coherency; struct iommufd_vdevice *vdev; bool destroying; +#ifdef CONFIG_IOMMU_LIVEUPDATE + bool liveupdate_preserved; +#endif }; static inline struct iommufd_device * diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h index 3087f5b2def8..f673a07cbc32 100644 --- a/include/linux/iommufd.h +++ b/include/linux/iommufd.h @@ -9,6 +9,7 @@ #include #include #include +#include #include #include #include @@ -215,6 +216,15 @@ int iommufd_access_rw(struct iommufd_access *access, unsigned long iova, int iommufd_vfio_compat_ioas_get_id(struct iommufd_ctx *ictx, u32 *out_ioas_id); int iommufd_vfio_compat_ioas_create(struct iommufd_ctx *ictx); int iommufd_vfio_compat_set_no_iommu(struct iommufd_ctx *ictx); + +#ifdef CONFIG_IOMMU_LIVEUPDATE +int iommufd_device_preserve(struct liveupdate_session *s, + struct iommufd_device *idev, + u64 *iommufd_tokenp); +void iommufd_device_unpreserve(struct liveupdate_session *s, + struct iommufd_device *idev); +bool iommufd_device_is_preserved(struct iommufd_device *idev); +#endif #else /* !CONFIG_IOMMUFD */ static inline struct iommufd_ctx *iommufd_ctx_from_file(struct file *file) { @@ -399,4 +409,27 @@ static inline void iommufd_viommu_destroy_mmap(struct iommufd_viommu *viommu, { _iommufd_destroy_mmap(viommu->ictx, &viommu->obj, offset); } + +#if !IS_ENABLED(CONFIG_IOMMU_LIVEUPDATE) || !IS_ENABLED(CONFIG_IOMMUFD) +/* + * vfio-pci live update works without IOMMU state preservation, so the device + * is still preserved, just without its IOMMU state. + */ +static inline int iommufd_device_preserve(struct liveupdate_session *s, + struct iommufd_device *idev, + u64 *iommufd_tokenp) +{ + return 0; +} + +static inline void iommufd_device_unpreserve(struct liveupdate_session *s, + struct iommufd_device *idev) +{ +} + +static inline bool iommufd_device_is_preserved(struct iommufd_device *idev) +{ + return false; +} +#endif #endif -- 2.56.0.506.g506a7eabc5-goog