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/filetable.h | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 66 insertions(+) create mode 100644 io_uring/filetable.h (limited to 'io_uring/filetable.h') diff --git a/io_uring/filetable.h b/io_uring/filetable.h new file mode 100644 index 000000000..c348233a3 --- /dev/null +++ b/io_uring/filetable.h @@ -0,0 +1,66 @@ +// SPDX-License-Identifier: GPL-2.0 +#ifndef IOU_FILE_TABLE_H +#define IOU_FILE_TABLE_H + +#include +#include "rsrc.h" + +bool io_alloc_file_tables(struct io_ring_ctx *ctx, struct io_file_table *table, unsigned nr_files); +void io_free_file_tables(struct io_ring_ctx *ctx, struct io_file_table *table); + +int io_fixed_fd_install(struct io_kiocb *req, unsigned int issue_flags, + struct file *file, unsigned int file_slot); +int __io_fixed_fd_install(struct io_ring_ctx *ctx, struct file *file, + unsigned int file_slot); +int io_fixed_fd_remove(struct io_ring_ctx *ctx, unsigned int offset); + +int io_register_file_alloc_range(struct io_ring_ctx *ctx, + struct io_uring_file_index_range __user *arg); + +io_req_flags_t io_file_get_flags(struct file *file); + +static inline void io_file_bitmap_clear(struct io_file_table *table, int bit) +{ + WARN_ON_ONCE(!test_bit(bit, table->bitmap)); + __clear_bit(bit, table->bitmap); + table->alloc_hint = bit; +} + +static inline void io_file_bitmap_set(struct io_file_table *table, int bit) +{ + WARN_ON_ONCE(test_bit(bit, table->bitmap)); + __set_bit(bit, table->bitmap); + table->alloc_hint = bit + 1; +} + +#define FFS_NOWAIT 0x1UL +#define FFS_ISREG 0x2UL +#define FFS_MASK ~(FFS_NOWAIT|FFS_ISREG) + +static inline unsigned int io_slot_flags(struct io_rsrc_node *node) +{ + + return (node->file_ptr & ~FFS_MASK) << REQ_F_SUPPORT_NOWAIT_BIT; +} + +static inline struct file *io_slot_file(struct io_rsrc_node *node) +{ + return (struct file *)(node->file_ptr & FFS_MASK); +} + +static inline void io_fixed_file_set(struct io_rsrc_node *node, + struct file *file) +{ + node->file_ptr = (unsigned long)file | + (io_file_get_flags(file) >> REQ_F_SUPPORT_NOWAIT_BIT); +} + +static inline void io_file_table_set_alloc_range(struct io_ring_ctx *ctx, + unsigned off, unsigned len) +{ + ctx->file_alloc_start = off; + ctx->file_alloc_end = off + len; + ctx->file_table.alloc_hint = ctx->file_alloc_start; +} + +#endif -- cgit v1.3.1