On 22.07.2024 12:18, Andrew Cooper wrote:
> --- a/xen/arch/x86/efi/efi-boot.h
> +++ b/xen/arch/x86/efi/efi-boot.h
> @@ -738,29 +738,30 @@ static void __init efi_arch_handle_module(const struct
> file *file,
>
> static void __init efi_arch_cpu(void)
> {
> - uint32_t eax = cpuid_eax(0x80000000U);
> + uint32_t eax;
> uint32_t *caps = boot_cpu_data.x86_capability;
>
> boot_tsc_stamp = rdtsc();
>
> caps[FEATURESET_1c] = cpuid_ecx(1);
>
> - if ( (eax >> 16) == 0x8000 && eax > 0x80000000U )
> - {
> - caps[FEATURESET_e1d] = cpuid_edx(0x80000001U);
> + eax = cpuid_eax(0x80000000U);
> + if ( (eax >> 16) != 0x8000 || eax < 0x80000000U )
Only in the context of the further discussion with Alejandro I've spotted
that the rhs of the || is now dead code. A proper transformation of the
earlier condition would have required <= in place of <.
Jan
