Re: [PATCH 10/61] KVM: x86: Clean up CPUID 0x7 sub-leaf loop

From: Vitaly Kuznetsov
Date: Fri Feb 21 2020 - 09:20:31 EST


Sean Christopherson <sean.j.christopherson@xxxxxxxxx> writes:

> Refactor the sub-leaf loop for CPUID 0x7 to move the main leaf out of
> said loop. The emitted code savings is basically a mirage, as the
> handling of the main leaf can easily be split to its own helper to avoid
> code bloat.
>
> No functional change intended.
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
> ---
> arch/x86/kvm/cpuid.c | 18 +++++++++---------
> 1 file changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index 6e1685a16cca..b626893a11d5 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -573,16 +573,16 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
> case 7: {
> int i;
>
> - for (i = 0; ; ) {
> + do_cpuid_7_mask(entry, 0);
> +
> + for (i = 1; i <= entry->eax; i++) {
> + if (*nent >= maxnent)
> + goto out;
> +
> + do_host_cpuid(&entry[i], function, i);
> + ++*nent;
> +
> do_cpuid_7_mask(&entry[i], i);
> - if (i == entry->eax)
> - break;
> - if (*nent >= maxnent)
> - goto out;
> -
> - ++i;
> - do_host_cpuid(&entry[i], function, i);
> - ++*nent;
> }
> break;
> }

Reviewed-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>

--
Vitaly