linux-kernel - Re: [PATCH v8] KVM: LAPIC: Apply change to TDCR right away to the timer

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Date:   Fri, 6 Oct 2017 17:02:00 +0200
From:   Radim Krčmář <rkrcmar@...hat.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Wanpeng Li <kernellwp@...il.com>, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org, Wanpeng Li <wanpeng.li@...mail.com>
Subject: Re: [PATCH v8] KVM: LAPIC: Apply change to TDCR right away to the
 timer

2017-10-06 16:51+0200, Paolo Bonzini:
> On 06/10/2017 16:38, Wanpeng Li wrote:
> > +	now = ktime_get();
> > +	remaining = ktime_sub(apic->lapic_timer.target_expiration, now);
> 
> Still need to compare against zero here.  I guess Radim can do it.

I added the expression from v7 while applying, thanks.

	if (ktime_to_ns(remaining) < 0)
		remaining = 0;

> > +	ns_remaining_old = ktime_to_ns(remaining);
> > +	ns_remaining_new = mul_u64_u32_div(ns_remaining_old,
> > +                              apic->divide_count, old_divisor);
> > +
> > +	apic->lapic_timer.tscdeadline += nsec_to_cycles(apic->vcpu, ns_remaining_new) -
> > +                                     nsec_to_cycles(apic->vcpu, ns_remaining_old);
> > +	apic->lapic_timer.target_expiration = ktime_add_ns(now, ns_remaining_new);