Re: [PATCH] x86/kvm: Don't waste kvmclock memory if there is nopv parameter

From: Wanpeng Li
Date: Tue Mar 08 2022 - 20:37:10 EST


On Tue, 8 Mar 2022 at 20:13, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
>
> On 3/8/22 09:18, Wanpeng Li wrote:
> > From: Wanpeng Li <wanpengli@xxxxxxxxxxx>
> >
> > When the "nopv" command line parameter is used, it should not waste
> > memory for kvmclock.
> >
> > Signed-off-by: Wanpeng Li <wanpengli@xxxxxxxxxxx>
> > ---
> > arch/x86/kernel/kvmclock.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
> > index c5caa73..16333ba 100644
> > --- a/arch/x86/kernel/kvmclock.c
> > +++ b/arch/x86/kernel/kvmclock.c
> > @@ -239,7 +239,7 @@ static void __init kvmclock_init_mem(void)
> >
> > static int __init kvm_setup_vsyscall_timeinfo(void)
> > {
> > - if (!kvm_para_available() || !kvmclock)
> > + if (!kvm_para_available() || !kvmclock || nopv)
> > return 0;
> >
> > kvmclock_init_mem();
>
> Perhaps instead !kvm_para_available() && nopv should clear the kvmclock
> variable?

Do you mean if (!kvm_para_available() && nopv) return 0? I
misunderstand why they are the same. :)

Wanpeng