From: David Woodhouse <dwmw2@infradead.org>
To: Wanpeng Li <kernellwp@gmail.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: "Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Marcelo Tosatti" <mtosatti@redhat.com>
Subject: Re: [PATCH v7 1/2] KVM: LAPIC: Make lapic timer unpinned
Date: Wed, 09 Mar 2022 10:26:51 +0100 [thread overview]
Message-ID: <ab523b0e930129a100d306d0959445665eb69457.camel@infradead.org> (raw)
In-Reply-To: <1562376411-3533-2-git-send-email-wanpengli@tencent.com>
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On Sat, 2019-07-06 at 09:26 +0800, Wanpeng Li wrote:
> From: Wanpeng Li <wanpengli@tencent.com>
>
> Commit 61abdbe0bcc2 ("kvm: x86: make lapic hrtimer pinned") pinned the
> lapic timer to avoid to wait until the next kvm exit for the guest to
> see KVM_REQ_PENDING_TIMER set. There is another solution to give a kick
> after setting the KVM_REQ_PENDING_TIMER bit, make lapic timer unpinned
> will be used in follow up patches.
>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Radim Krčmář <rkrcmar@redhat.com>
> Cc: Marcelo Tosatti <mtosatti@redhat.com>
> Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
> ---
> arch/x86/kvm/lapic.c | 8 ++++----
> arch/x86/kvm/x86.c | 6 +-----
> 2 files changed, 5 insertions(+), 9 deletions(-)
...
> @@ -2510,7 +2510,7 @@ void __kvm_migrate_apic_timer(struct kvm_vcpu *vcpu)
>
> timer = &vcpu->arch.apic->lapic_timer.timer;
> if (hrtimer_cancel(timer))
> - hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
> + hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
> }
>
> /*
Wait, in that case why are we even bothering to cancel and restart the
timer? I thought the whole point of that was to pin it to the *new* CPU
that this vCPU is running on.
If not, can't we just kill __kvm_migrate_apic_timer() off completely
not?
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next prev parent reply other threads:[~2022-03-09 9:26 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-06 1:26 [PATCH v7 0/2] KVM: LAPIC: Implement Exitless Timer Wanpeng Li
2019-07-06 1:26 ` [PATCH v7 1/2] KVM: LAPIC: Make lapic timer unpinned Wanpeng Li
2022-03-09 9:26 ` David Woodhouse [this message]
2022-03-09 11:24 ` Marcelo Tosatti
2022-03-09 15:03 ` David Woodhouse
2019-07-06 1:26 ` [PATCH v7 2/2] KVM: LAPIC: Inject timer interrupt via posted interrupt Wanpeng Li
2019-07-17 16:27 ` Paolo Bonzini
[not found] ` <TY2PR02MB41600B4C6B9FF4A9F8CD957880F30@TY2PR02MB4160.apcprd02.prod.outlook.com>
2019-07-11 14:03 ` [PATCH v7 0/2] KVM: LAPIC: Implement Exitless Timer Paolo Bonzini
2019-07-17 0:30 ` Wanpeng Li
2019-08-21 4:16 ` Wanpeng Li
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