From: Paolo Bonzini <pbonzini@redhat.com>
To: Wanpeng Li <kernellwp@gmail.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: "Radim Krčmář" <rkrcmar@redhat.com>,
"Yunhong Jiang" <yunhong.jiang@intel.com>,
"Wanpeng Li" <wanpeng.li@hotmail.com>
Subject: Re: [PATCH 5/5] KVM: LAPIC: add APIC Timer periodic/oneshot mode VMX preemption timer support
Date: Mon, 17 Oct 2016 10:45:28 +0200 [thread overview]
Message-ID: <5b76de67-bbff-f677-2dbf-0fcbea48e473@redhat.com> (raw)
In-Reply-To: <1476690302-22158-6-git-send-email-wanpeng.li@hotmail.com>
On 17/10/2016 09:45, Wanpeng Li wrote:
> + remaining = ktime_sub(apic->lapic_timer.target_expiration, now);
> if (ktime_to_ns(remaining) < 0)
> remaining = ktime_set(0, 0);
>
> @@ -1351,13 +1352,28 @@ static void start_sw_period(struct kvm_lapic *apic)
> {
> ktime_t now;
>
> - /* lapic timer in oneshot or periodic mode */
> + now = apic->lapic_timer.timer.base->get_time();
> +
> + if (likely(ktime_compare(apic->lapic_timer.target_expiration, now)))
ktime_after, not ktime_compare. Can be fixed on commit, I guess.
Paolo
> + hrtimer_start(&apic->lapic_timer.timer,
> + apic->lapic_timer.target_expiration,
> + HRTIMER_MODE_ABS_PINNED);
> + else
> + apic_timer_expired(apic);
> +}
> +
> +static bool set_target_expiration(struct kvm_lapic *apic)
> +{
> + ktime_t now;
> + u64 tscl = rdtsc();
> +
> now = apic->lapic_timer.timer.base->get_time();
> apic->lapic_timer.period = (u64)kvm_lapic_get_reg(apic, APIC_TMICT)
> - * APIC_BUS_CYCLE_NS * apic->divide_count;
> + * APIC_BUS_CYCLE_NS * apic->divide_count;
>
> if (!apic->lapic_timer.period)
> - return;
> + return false;
> /*
> * Do not allow the guest to program periodic timers with small
> * interval, since the hrtimers are not throttled by the host
> @@ -1376,10 +1392,6 @@ static void start_sw_period(struct kvm_lapic *apic)
> }
> }
>
> - hrtimer_start(&apic->lapic_timer.timer,
> - ktime_add_ns(now, apic->lapic_timer.period),
> - HRTIMER_MODE_ABS_PINNED);
> -
> apic_debug("%s: bus cycle is %" PRId64 "ns, now 0x%016"
> PRIx64 ", "
> "timer initial count 0x%x, period %lldns, "
> @@ -1389,6 +1401,12 @@ static void start_sw_period(struct kvm_lapic *apic)
> apic->lapic_timer.period,
> ktime_to_ns(ktime_add_ns(now,
> apic->lapic_timer.period)));
> +
> + apic->lapic_timer.tscdeadline = kvm_read_l1_tsc(apic->vcpu, tscl) +
> + nsec_to_cycles(apic->vcpu, apic->lapic_timer.period);
> + apic->lapic_timer.target_expiration = ktime_add_ns(now, apic->lapic_timer.period);
> +
> + return true;
> }
>
> bool kvm_lapic_hv_timer_in_use(struct kvm_vcpu *vcpu)
> @@ -1406,22 +1424,12 @@ static void cancel_hv_timer(struct kvm_lapic *apic)
> apic->lapic_timer.hv_timer_in_use = false;
> }
>
> -void kvm_lapic_expired_hv_timer(struct kvm_vcpu *vcpu)
> -{
> - struct kvm_lapic *apic = vcpu->arch.apic;
> -
> - WARN_ON(!apic->lapic_timer.hv_timer_in_use);
> - WARN_ON(swait_active(&vcpu->wq));
> - cancel_hv_timer(apic);
> - apic_timer_expired(apic);
> -}
> -EXPORT_SYMBOL_GPL(kvm_lapic_expired_hv_timer);
> -
> static bool start_hv_timer(struct kvm_lapic *apic)
> {
> u64 tscdeadline = apic->lapic_timer.tscdeadline;
>
> - if (atomic_read(&apic->lapic_timer.pending) ||
> + if ((atomic_read(&apic->lapic_timer.pending) &&
> + !apic_lvtt_period(apic)) ||
> kvm_x86_ops->set_hv_timer(apic->vcpu, tscdeadline)) {
> if (apic->lapic_timer.hv_timer_in_use)
> cancel_hv_timer(apic);
> @@ -1430,7 +1438,8 @@ static bool start_hv_timer(struct kvm_lapic *apic)
> hrtimer_cancel(&apic->lapic_timer.timer);
>
> /* In case the sw timer triggered in the window */
> - if (atomic_read(&apic->lapic_timer.pending))
> + if (atomic_read(&apic->lapic_timer.pending) &&
> + !apic_lvtt_period(apic))
> cancel_hv_timer(apic);
> }
> trace_kvm_hv_timer_state(apic->vcpu->vcpu_id,
> @@ -1438,14 +1447,42 @@ static bool start_hv_timer(struct kvm_lapic *apic)
> return apic->lapic_timer.hv_timer_in_use;
> }
>
> +void kvm_lapic_expired_hv_timer(struct kvm_vcpu *vcpu)
> +{
> + struct kvm_lapic *apic = vcpu->arch.apic;
> +
> + WARN_ON(!apic->lapic_timer.hv_timer_in_use);
> + WARN_ON(swait_active(&vcpu->wq));
> + cancel_hv_timer(apic);
> + apic_timer_expired(apic);
> +
> + if (apic_lvtt_period(apic) &&
> + set_target_expiration(apic) &&
> + !start_hv_timer(apic))
> + start_sw_period(apic);
> +}
> +EXPORT_SYMBOL_GPL(kvm_lapic_expired_hv_timer);
> +
> void kvm_lapic_switch_to_hv_timer(struct kvm_vcpu *vcpu)
> {
> struct kvm_lapic *apic = vcpu->arch.apic;
>
> WARN_ON(apic->lapic_timer.hv_timer_in_use);
>
> - if (apic_lvtt_tscdeadline(apic))
> - start_hv_timer(apic);
> + if (apic_lvtt_period(apic) || apic_lvtt_oneshot(apic)) {
> + ktime_t remaining, now;
> + u64 tscl = rdtsc();
> +
> + now = apic->lapic_timer.timer.base->get_time();
> + remaining = hrtimer_get_remaining(&apic->lapic_timer.timer);
> + if (ktime_to_ns(remaining) < 0)
> + remaining = ktime_set(0, 0);
> +
> + apic->lapic_timer.tscdeadline = kvm_read_l1_tsc(apic->vcpu, tscl) +
> + nsec_to_cycles(apic->vcpu, ktime_to_ns(remaining));
> + apic->lapic_timer.target_expiration = ktime_add_ns(now, ktime_to_ns(remaining));
> + }
> + start_hv_timer(apic);
> }
> EXPORT_SYMBOL_GPL(kvm_lapic_switch_to_hv_timer);
>
> @@ -1462,7 +1499,10 @@ void kvm_lapic_switch_to_sw_timer(struct kvm_vcpu *vcpu)
> if (atomic_read(&apic->lapic_timer.pending))
> return;
>
> - start_sw_tscdeadline(apic);
> + if (apic_lvtt_period(apic) || apic_lvtt_oneshot(apic))
> + start_sw_period(apic);
> + else if (apic_lvtt_tscdeadline(apic))
> + start_sw_tscdeadline(apic);
> }
> EXPORT_SYMBOL_GPL(kvm_lapic_switch_to_sw_timer);
>
> @@ -1470,9 +1510,11 @@ static void start_apic_timer(struct kvm_lapic *apic)
> {
> atomic_set(&apic->lapic_timer.pending, 0);
>
> - if (apic_lvtt_period(apic) || apic_lvtt_oneshot(apic))
> - start_sw_period(apic);
> - else if (apic_lvtt_tscdeadline(apic)) {
> + if (apic_lvtt_period(apic) || apic_lvtt_oneshot(apic)) {
> + if (set_target_expiration(apic) &&
> + !(kvm_x86_ops->set_hv_timer && start_hv_timer(apic)))
> + start_sw_period(apic);
> + } else if (apic_lvtt_tscdeadline(apic)) {
> if (!(kvm_x86_ops->set_hv_timer && start_hv_timer(apic)))
> start_sw_tscdeadline(apic);
> }
> @@ -2005,8 +2047,11 @@ void kvm_inject_apic_timer_irqs(struct kvm_vcpu *vcpu)
>
> if (atomic_read(&apic->lapic_timer.pending) > 0) {
> kvm_apic_local_deliver(apic, APIC_LVTT);
> - if (apic_lvtt_tscdeadline(apic))
> + if (!(apic_lvtt_period(apic) &&
> + kvm_lapic_hv_timer_in_use(vcpu))) {
> apic->lapic_timer.tscdeadline = 0;
> + apic->lapic_timer.target_expiration = ktime_set(0, 0);
> + }
> atomic_set(&apic->lapic_timer.pending, 0);
> }
> }
> diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
> index 031db26..e0c8023 100644
> --- a/arch/x86/kvm/lapic.h
> +++ b/arch/x86/kvm/lapic.h
> @@ -15,6 +15,7 @@
> struct kvm_timer {
> struct hrtimer timer;
> s64 period; /* unit: ns */
> + ktime_t target_expiration;
> u32 timer_mode;
> u32 timer_mode_mask;
> u64 tscdeadline;
>
next prev parent reply other threads:[~2016-10-17 8:45 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-17 7:44 [PATCH 0/5] KVM: LAPIC: Add " Wanpeng Li
2016-10-17 7:44 ` [PATCH 1/5] KVM: LAPIC: extract start_sw_period() to handle periodic/oneshot mode Wanpeng Li
2016-10-17 7:44 ` [PATCH 2/5] KVM: LAPIC: guarantee the timer is in tsc-deadline mode Wanpeng Li
2016-10-17 7:45 ` [PATCH 3/5] KVM: LAPIC: introduce kvm_get_lapic_target_expiration_tsc() Wanpeng Li
2016-10-17 7:45 ` [PATCH 4/5] KVM: LAPIC: rename start/cancel_hv_tscdeadline to start/cancel_hv_timer Wanpeng Li
2016-10-17 7:45 ` [PATCH 5/5] KVM: LAPIC: add APIC Timer periodic/oneshot mode VMX preemption timer support Wanpeng Li
2016-10-17 8:45 ` Paolo Bonzini [this message]
2016-10-19 19:28 ` Radim Krčmář
2016-10-19 22:57 ` Wanpeng Li
2016-10-20 18:10 ` Radim Krčmář
2016-10-21 13:38 ` Wanpeng Li
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5b76de67-bbff-f677-2dbf-0fcbea48e473@redhat.com \
--to=pbonzini@redhat.com \
--cc=kernellwp@gmail.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=rkrcmar@redhat.com \
--cc=wanpeng.li@hotmail.com \
--cc=yunhong.jiang@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®