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 --- drivers/md/dm-vdo/permassert.h | 45 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 drivers/md/dm-vdo/permassert.h (limited to 'drivers/md/dm-vdo/permassert.h') diff --git a/drivers/md/dm-vdo/permassert.h b/drivers/md/dm-vdo/permassert.h new file mode 100644 index 000000000..c34f2ba65 --- /dev/null +++ b/drivers/md/dm-vdo/permassert.h @@ -0,0 +1,45 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright 2023 Red Hat + */ + +#ifndef PERMASSERT_H +#define PERMASSERT_H + +#include + +#include "errors.h" + +/* Utilities for asserting that certain conditions are met */ + +#define STRINGIFY(X) #X + +/* + * A hack to apply the "warn if unused" attribute to an integral expression. + * + * Since GCC doesn't propagate the warn_unused_result attribute to conditional expressions + * incorporating calls to functions with that attribute, this function can be used to wrap such an + * expression. With optimization enabled, this function contributes no additional instructions, but + * the warn_unused_result attribute still applies to the code calling it. + */ +static inline int __must_check vdo_must_use(int value) +{ + return value; +} + +/* Assert that an expression is true and return an error if it is not. */ +#define VDO_ASSERT(expr, ...) vdo_must_use(__VDO_ASSERT(expr, __VA_ARGS__)) + +/* Log a message if the expression is not true. */ +#define VDO_ASSERT_LOG_ONLY(expr, ...) __VDO_ASSERT(expr, __VA_ARGS__) + +#define __VDO_ASSERT(expr, ...) \ + (likely(expr) ? VDO_SUCCESS \ + : vdo_assertion_failed(STRINGIFY(expr), __FILE__, __LINE__, __VA_ARGS__)) + +/* Log an assertion failure message. */ +int vdo_assertion_failed(const char *expression_string, const char *file_name, + int line_number, const char *format, ...) + __printf(4, 5); + +#endif /* PERMASSERT_H */ -- cgit v1.3.1