diff options
| author | Alexey Dobriyan <adobriyan@gmail.com> | 2024-08-02 18:42:52 +0300 |
|---|---|---|
| committer | Juergen Gross <jgross@suse.com> | 2024-09-12 08:25:12 +0200 |
| commit | 416a33c9afcef24d8b48e414d08d4ae4472aa669 (patch) | |
| tree | 7e110e891366473155eb5bac442b5d0c6fe1a51f | |
| parent | 661362e3dcab464d6b6976c019fd5b5433bda85f (diff) | |
x86/cpu: fix unbootable VMs by inlining memcmp() in hypervisor_cpuid_base()
If this memcmp() is not inlined then PVH early boot code can call
into KASAN-instrumented memcmp() which results in unbootable VMs:
pvh_start_xen
xen_prepare_pvh
xen_cpuid_base
hypervisor_cpuid_base
memcmp
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Juergen Gross <jgross@suse.com>
Message-ID: <20240802154253.482658-2-adobriyan@gmail.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
| -rw-r--r-- | arch/x86/include/asm/cpuid.h | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/x86/include/asm/cpuid.h b/arch/x86/include/asm/cpuid.h index 6b122a31da06..80cc6386d7b1 100644 --- a/arch/x86/include/asm/cpuid.h +++ b/arch/x86/include/asm/cpuid.h @@ -196,7 +196,12 @@ static inline uint32_t hypervisor_cpuid_base(const char *sig, uint32_t leaves) for_each_possible_hypervisor_cpuid_base(base) { cpuid(base, &eax, &signature[0], &signature[1], &signature[2]); - if (!memcmp(sig, signature, 12) && + /* + * This must not compile to "call memcmp" because it's called + * from PVH early boot code before instrumentation is set up + * and memcmp() itself may be instrumented. + */ + if (!__builtin_memcmp(sig, signature, 12) && (leaves == 0 || ((eax - base) >= leaves))) return base; } |