bug: introduce ASSERT_STRUCT_OFFSET

ASSERT_STRUCT_OFFSET allows to assert during the build of
the kernel that a field in a struct have an expected offset.

KVM used to have such macro, but there is almost nothing KVM specific
in it so move it to build_bug.h, so that it can be used in other
places in KVM.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20221025124741.228045-10-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Maxim Levitsky 2022-10-25 15:47:27 +03:00 committed by Paolo Bonzini
parent 00009406f0
commit 07a368b3f5
2 changed files with 11 additions and 3 deletions

View File

@ -208,9 +208,8 @@ struct __packed vmcs12 {
/*
* For save/restore compatibility, the vmcs12 field offsets must not change.
*/
#define CHECK_OFFSET(field, loc) \
BUILD_BUG_ON_MSG(offsetof(struct vmcs12, field) != (loc), \
"Offset of " #field " in struct vmcs12 has changed.")
#define CHECK_OFFSET(field, loc) \
ASSERT_STRUCT_OFFSET(struct vmcs12, field, loc)
static inline void vmx_check_vmcs12_offsets(void)
{

View File

@ -77,4 +77,13 @@
#define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr)
#define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
/*
* Compile time check that field has an expected offset
*/
#define ASSERT_STRUCT_OFFSET(type, field, expected_offset) \
BUILD_BUG_ON_MSG(offsetof(type, field) != (expected_offset), \
"Offset of " #field " in " #type " has changed.")
#endif /* _LINUX_BUILD_BUG_H */