From 93de2a6a4b91b72607136dd656edf03fb399d27f Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 23 Sep 2026 09:37:21 -0700 Subject: KVM: SEV: Do cache maintenance on the source VM during intra-host migration Manually perform cache maintenance on the source VM during intra-host migration to ensure no stale data is left in CPU caches after the VM is destroyed. Because the source VM is "converted" to a non-SEV VM, KVM's memory reclaim flows won't trigger cache maintenance, e.g. when all guest memory is reclaimed in response to detaching from the mmu_notifier. Note, relying on the destination VM to do cache maintenance isn't an option as KVM doesn't require identical guest memory configurations, i.e. the source VM may have access to memory that the destination VM does not. Enforcing equivalent memory configurations is infeasible, as it would require a *deep* comparison of memslots, e.g. to verify that not only are the memslot identical, but what the memslots point at is also identical. Fixes: b56639318bb2 ("KVM: SEV: Add support for SEV intra host migration") Cc: stable@vger.kernel.org Reported-by: Stefan Teodorescu Signed-off-by: Sean Christopherson Message-ID: <20260923163721.1584779-3-seanjc@google.com> Signed-off-by: Paolo Bonzini --- io_uring/rsrc.h | 156 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 156 insertions(+) create mode 100644 io_uring/rsrc.h (limited to 'io_uring/rsrc.h') diff --git a/io_uring/rsrc.h b/io_uring/rsrc.h new file mode 100644 index 000000000..9ef88383b --- /dev/null +++ b/io_uring/rsrc.h @@ -0,0 +1,156 @@ +// SPDX-License-Identifier: GPL-2.0 +#ifndef IOU_RSRC_H +#define IOU_RSRC_H + +#include +#include +#include +#include + +#define IO_VEC_CACHE_SOFT_CAP 256 + +enum { + IORING_RSRC_FILE = 0, + IORING_RSRC_BUFFER = 1, +}; + +struct io_rsrc_node { + unsigned char type; + int refs; + + u64 tag; + union { + unsigned long file_ptr; + struct io_mapped_ubuf *buf; + }; +}; + +enum { + IO_REGBUF_F_KBUF = 1, +}; + +struct io_mapped_ubuf { + u64 ubuf; + size_t len; + unsigned int nr_bvecs; + unsigned int folio_shift; + refcount_t refs; + u8 flags; + u8 dir; + void (*release)(void *); + void *priv; + struct bio_vec bvec[] __counted_by(nr_bvecs); +}; + +struct io_imu_folio_data { + /* Head folio can be partially included in the fixed buf */ + unsigned int nr_pages_head; + /* For non-head/tail folios, has to be fully included */ + unsigned int nr_pages_mid; + unsigned int folio_shift; + unsigned int nr_folios; + unsigned long first_folio_page_idx; +}; + +bool io_rsrc_cache_init(struct io_ring_ctx *ctx); +void io_rsrc_cache_free(struct io_ring_ctx *ctx); +struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx, int type); +void io_free_rsrc_node(struct io_ring_ctx *ctx, struct io_rsrc_node *node); +void io_rsrc_data_free(struct io_ring_ctx *ctx, struct io_rsrc_data *data); +int io_rsrc_data_alloc(struct io_rsrc_data *data, unsigned nr); + +struct io_rsrc_node *io_find_buf_node(struct io_kiocb *req, + unsigned issue_flags); +int io_import_reg_buf(struct io_kiocb *req, struct iov_iter *iter, + u64 buf_addr, size_t len, int ddir, + unsigned issue_flags); +int io_import_reg_vec(int ddir, struct iov_iter *iter, + struct io_kiocb *req, struct iou_vec *vec, + unsigned nr_iovs, unsigned issue_flags); +int io_prep_reg_iovec(struct io_kiocb *req, struct iou_vec *iv, + const struct iovec __user *uvec, size_t uvec_segs); + +int io_register_clone_buffers(struct io_ring_ctx *ctx, void __user *arg); +int io_sqe_buffers_unregister(struct io_ring_ctx *ctx); +int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg, + unsigned int nr_args, u64 __user *tags); +int io_sqe_files_unregister(struct io_ring_ctx *ctx); +int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, + unsigned nr_args, u64 __user *tags); + +int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg, + unsigned nr_args); +int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg, + unsigned size, unsigned type); +int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg, + unsigned int size, unsigned int type); +int io_validate_user_buf_range(u64 uaddr, u64 ulen); + +bool io_check_coalesce_buffer(struct page **page_array, int nr_pages, + struct io_imu_folio_data *data); + +static inline struct io_rsrc_node *io_rsrc_node_lookup(struct io_rsrc_data *data, + unsigned int index) +{ + if (index < data->nr) + return data->nodes[array_index_nospec(index, data->nr)]; + return NULL; +} + +static inline void io_put_rsrc_node(struct io_ring_ctx *ctx, struct io_rsrc_node *node) +{ + lockdep_assert_held(&ctx->uring_lock); + if (!--node->refs) + io_free_rsrc_node(ctx, node); +} + +static inline bool io_reset_rsrc_node(struct io_ring_ctx *ctx, + struct io_rsrc_data *data, + unsigned int index) +{ + struct io_rsrc_node *node; + + if (index >= data->nr) + return false; + index = array_index_nospec(index, data->nr); + node = data->nodes[index]; + if (!node) + return false; + io_put_rsrc_node(ctx, node); + data->nodes[index] = NULL; + return true; +} + +int io_files_update(struct io_kiocb *req, unsigned int issue_flags); +int io_files_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); + +int __io_account_mem(struct user_struct *user, unsigned long nr_pages); +int io_account_mem(struct user_struct *user, struct mm_struct *mm_account, + unsigned long nr_pages); +void io_unaccount_mem(struct user_struct *user, struct mm_struct *mm_account, + unsigned long nr_pages); + +static inline void __io_unaccount_mem(struct user_struct *user, + unsigned long nr_pages) +{ + atomic_long_sub(nr_pages, &user->locked_vm); +} + +void io_vec_free(struct iou_vec *iv); +int io_vec_realloc(struct iou_vec *iv, unsigned nr_entries); + +static inline void io_vec_reset_iovec(struct iou_vec *iv, + struct iovec *iovec, unsigned nr) +{ + io_vec_free(iv); + iv->iovec = iovec; + iv->nr = nr; +} + +static inline void io_alloc_cache_vec_kasan(struct iou_vec *iv) +{ + if (IS_ENABLED(CONFIG_KASAN)) + io_vec_free(iv); +} + +#endif -- cgit v1.3.1