lkml.org 
[lkml]   [2022]   [Mar]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v7 1/2] KVM: LAPIC: Make lapic timer unpinned
From
Date
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?
[unhandled content-type:application/pkcs7-signature]
\
 
 \ /
  Last update: 2022-03-09 10:27    [W:0.121 / U:0.052 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site