Enable IOMMUFD KVM HW page table object to serve as proxy between KVM and IOMMU driver. Config IOMMUFD_KVM_HWPT is added to turn on/off this ability. KVM HW page table object first gets KVM TDP fd object via KVM exported interface kvm_tdp_fd_get() and then queries KVM for vendor meta data of page tables exported (shared) by KVM. It then passes the meta data to IOMMU driver to create a IOMMU_DOMAIN_KVM domain via op domain_alloc_kvm. IOMMU driver is responsible to check compatibility between IOMMU hardware and the KVM exported page tables. After successfully creating IOMMU_DOMAIN_KVM domain, IOMMUFD KVM HW page table object registers invalidation callback to KVM to receive invalidation notifications. It then passes the notification to IOMMU driver via op cache_invalidate_kvm to invalidate hardware TLBs. Signed-off-by: Yan Zhao <yan.y.zhao@xxxxxxxxx> --- drivers/iommu/iommufd/Kconfig | 10 ++ drivers/iommu/iommufd/Makefile | 1 + drivers/iommu/iommufd/hw_pagetable_kvm.c | 183 +++++++++++++++++++++++ drivers/iommu/iommufd/iommufd_private.h | 9 ++ 4 files changed, 203 insertions(+) create mode 100644 drivers/iommu/iommufd/hw_pagetable_kvm.c diff --git a/drivers/iommu/iommufd/Kconfig b/drivers/iommu/iommufd/Kconfig index 99d4b075df49e..d79e0c1e00a4d 100644 --- a/drivers/iommu/iommufd/Kconfig +++ b/drivers/iommu/iommufd/Kconfig @@ -32,6 +32,16 @@ config IOMMUFD_VFIO_CONTAINER Unless testing IOMMUFD, say N here. +config IOMMUFD_KVM_HWPT + bool "Supports KVM managed HW page tables" + default n + help + Selecting this option will allow IOMMUFD to create IOMMU stage 2 + page tables whose paging structure and mappings are managed by + KVM MMU. IOMMUFD serves as proxy between KVM and IOMMU driver to + allow IOMMU driver to get paging structure meta data and cache + invalidate notifications from KVM. + config IOMMUFD_TEST bool "IOMMU Userspace API Test support" depends on DEBUG_KERNEL diff --git a/drivers/iommu/iommufd/Makefile b/drivers/iommu/iommufd/Makefile index 34b446146961c..ae1e0b5c300dc 100644 --- a/drivers/iommu/iommufd/Makefile +++ b/drivers/iommu/iommufd/Makefile @@ -8,6 +8,7 @@ iommufd-y := \ pages.o \ vfio_compat.o +iommufd-$(CONFIG_IOMMUFD_KVM_HWPT) += hw_pagetable_kvm.o iommufd-$(CONFIG_IOMMUFD_TEST) += selftest.o obj-$(CONFIG_IOMMUFD) += iommufd.o diff --git a/drivers/iommu/iommufd/hw_pagetable_kvm.c b/drivers/iommu/iommufd/hw_pagetable_kvm.c new file mode 100644 index 0000000000000..e0e205f384ed5 --- /dev/null +++ b/drivers/iommu/iommufd/hw_pagetable_kvm.c @@ -0,0 +1,183 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <linux/iommu.h> +#include <uapi/linux/iommufd.h> +#include <linux/kvm_tdp_fd.h> + +#include "../iommu-priv.h" +#include "iommufd_private.h" + +static void iommufd_kvmtdp_invalidate(void *data, + unsigned long start, unsigned long size) +{ + void (*invalidate_fn)(struct iommu_domain *domain, + unsigned long iova, unsigned long size); + struct iommufd_hw_pagetable *hwpt = data; + + if (!hwpt || !hwpt_is_kvm(hwpt)) + return; + + invalidate_fn = hwpt->domain->ops->cache_invalidate_kvm; + + if (!invalidate_fn) + return; + + invalidate_fn(hwpt->domain, start, size); + +} + +struct kvm_tdp_importer_ops iommufd_import_ops = { + .invalidate = iommufd_kvmtdp_invalidate, +}; + +static inline int kvmtdp_register(struct kvm_tdp_fd *tdp_fd, void *data) +{ + if (!tdp_fd->ops->register_importer || !tdp_fd->ops->register_importer) + return -EOPNOTSUPP; + + return tdp_fd->ops->register_importer(tdp_fd, &iommufd_import_ops, data); +} + +static inline void kvmtdp_unregister(struct kvm_tdp_fd *tdp_fd) +{ + WARN_ON(!tdp_fd->ops->unregister_importer); + + tdp_fd->ops->unregister_importer(tdp_fd, &iommufd_import_ops); +} + +static inline void *kvmtdp_get_metadata(struct kvm_tdp_fd *tdp_fd) +{ + if (!tdp_fd->ops->get_metadata) + return ERR_PTR(-EOPNOTSUPP); + + return tdp_fd->ops->get_metadata(tdp_fd); +} + +/* + * Get KVM TDP FD object and ensure tdp_fd->ops is available + */ +static inline struct kvm_tdp_fd *kvmtdp_get(int fd) +{ + struct kvm_tdp_fd *tdp_fd = NULL; + struct kvm_tdp_fd *(*get_func)(int fd) = NULL; + void (*put_func)(struct kvm_tdp_fd *) = NULL; + + get_func = symbol_get(kvm_tdp_fd_get); + + if (!get_func) + goto out; + + put_func = symbol_get(kvm_tdp_fd_put); + if (!put_func) + goto out; + + tdp_fd = get_func(fd); + if (!tdp_fd) + goto out; + + if (tdp_fd->ops) { + /* success */ + goto out; + } + + put_func(tdp_fd); + tdp_fd = NULL; + +out: + if (get_func) + symbol_put(kvm_tdp_fd_get); + + if (put_func) + symbol_put(kvm_tdp_fd_put); + + return tdp_fd; +} + +static void kvmtdp_put(struct kvm_tdp_fd *tdp_fd) +{ + void (*put_func)(struct kvm_tdp_fd *) = NULL; + + put_func = symbol_get(kvm_tdp_fd_put); + WARN_ON(!put_func); + + put_func(tdp_fd); + + symbol_put(kvm_tdp_fd_put); +} + +void iommufd_hwpt_kvm_destroy(struct iommufd_object *obj) +{ + struct kvm_tdp_fd *tdp_fd; + struct iommufd_hwpt_kvm *hwpt_kvm = + container_of(obj, struct iommufd_hwpt_kvm, common.obj); + + if (hwpt_kvm->common.domain) + iommu_domain_free(hwpt_kvm->common.domain); + + tdp_fd = hwpt_kvm->context; + kvmtdp_unregister(tdp_fd); + kvmtdp_put(tdp_fd); +} + +void iommufd_hwpt_kvm_abort(struct iommufd_object *obj) +{ + iommufd_hwpt_kvm_destroy(obj); +} + +struct iommufd_hwpt_kvm * +iommufd_hwpt_kvm_alloc(struct iommufd_ctx *ictx, + struct iommufd_device *idev, u32 flags, + const struct iommu_hwpt_kvm_info *kvm_data) +{ + + const struct iommu_ops *ops = dev_iommu_ops(idev->dev); + struct iommufd_hwpt_kvm *hwpt_kvm; + struct iommufd_hw_pagetable *hwpt; + struct kvm_tdp_fd *tdp_fd; + void *meta_data; + int rc; + + if (!ops->domain_alloc_kvm) + return ERR_PTR(-EOPNOTSUPP); + + if (kvm_data->fd < 0) + return ERR_PTR(-EINVAL); + + tdp_fd = kvmtdp_get(kvm_data->fd); + if (!tdp_fd) + return ERR_PTR(-EOPNOTSUPP); + + meta_data = kvmtdp_get_metadata(tdp_fd); + if (!meta_data || IS_ERR(meta_data)) { + rc = -EFAULT; + goto out_put_tdp; + } + + hwpt_kvm = __iommufd_object_alloc(ictx, hwpt_kvm, IOMMUFD_OBJ_HWPT_KVM, + common.obj); + if (IS_ERR(hwpt_kvm)) { + rc = PTR_ERR(hwpt_kvm); + goto out_put_tdp; + } + + hwpt_kvm->context = tdp_fd; + hwpt = &hwpt_kvm->common; + + hwpt->domain = ops->domain_alloc_kvm(idev->dev, flags, meta_data); + if (IS_ERR(hwpt->domain)) { + rc = PTR_ERR(hwpt->domain); + hwpt->domain = NULL; + goto out_abort; + } + + rc = kvmtdp_register(tdp_fd, hwpt); + if (rc) + goto out_abort; + + return hwpt_kvm; + +out_abort: + iommufd_object_abort_and_destroy(ictx, &hwpt->obj); +out_put_tdp: + kvmtdp_put(tdp_fd); + return ERR_PTR(rc); +} diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h index a46a6e3e537f9..2c3149b1d5b55 100644 --- a/drivers/iommu/iommufd/iommufd_private.h +++ b/drivers/iommu/iommufd/iommufd_private.h @@ -432,6 +432,14 @@ static inline bool iommufd_selftest_is_mock_dev(struct device *dev) #endif struct iommu_hwpt_kvm_info; +#ifdef CONFIG_IOMMUFD_KVM_HWPT +struct iommufd_hwpt_kvm * +iommufd_hwpt_kvm_alloc(struct iommufd_ctx *ictx, + struct iommufd_device *idev, u32 flags, + const struct iommu_hwpt_kvm_info *kvm_data); +void iommufd_hwpt_kvm_abort(struct iommufd_object *obj); +void iommufd_hwpt_kvm_destroy(struct iommufd_object *obj); +#else static inline struct iommufd_hwpt_kvm * iommufd_hwpt_kvm_alloc(struct iommufd_ctx *ictx, struct iommufd_device *idev, u32 flags, @@ -447,5 +455,6 @@ static inline void iommufd_hwpt_kvm_abort(struct iommufd_object *obj) static inline void iommufd_hwpt_kvm_destroy(struct iommufd_object *obj) { } +#endif #endif -- 2.17.1