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/tctx.h | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) create mode 100644 io_uring/tctx.h (limited to 'io_uring/tctx.h') diff --git a/io_uring/tctx.h b/io_uring/tctx.h new file mode 100644 index 000000000..76ad1ad45 --- /dev/null +++ b/io_uring/tctx.h @@ -0,0 +1,34 @@ +// SPDX-License-Identifier: GPL-2.0 + +struct io_tctx_node { + struct list_head ctx_node; + struct task_struct *task; + struct io_ring_ctx *ctx; +}; + +struct io_uring_task *io_uring_alloc_task_context(struct task_struct *task, + struct io_ring_ctx *ctx); +void io_uring_del_tctx_node(unsigned long index); +int __io_uring_add_tctx_node(struct io_ring_ctx *ctx); +int __io_uring_add_tctx_node_from_submit(struct io_ring_ctx *ctx); +void io_uring_clean_tctx(struct io_uring_task *tctx); +void io_uring_free_tctx(struct task_struct *tsk); + +void io_uring_unreg_ringfd(void); +int io_ringfd_register(struct io_ring_ctx *ctx, void __user *__arg, + unsigned nr_args); +int io_ringfd_unregister(struct io_ring_ctx *ctx, void __user *__arg, + unsigned nr_args); + +/* + * Note that this task has used io_uring. We use it for cancelation purposes. + */ +static inline int io_uring_add_tctx_node(struct io_ring_ctx *ctx) +{ + struct io_uring_task *tctx = current->io_uring; + + if (likely(tctx && tctx->last == ctx)) + return 0; + + return __io_uring_add_tctx_node_from_submit(ctx); +} -- cgit v1.3.1