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Groups > linux.kernel > #1651445 > unrolled thread
| Started by | Paolo Bonzini <pbonzini@redhat.com> |
|---|---|
| First post | 2017-05-26 18:00 +0200 |
| Last post | 2017-05-27 03:30 +0200 |
| Articles | 2 — 2 participants |
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Re: [PATCH] KVM: X86: Fix preempt the preemption timer cancel Paolo Bonzini <pbonzini@redhat.com> - 2017-05-26 18:00 +0200
Re: [PATCH] KVM: X86: Fix preempt the preemption timer cancel Wanpeng Li <kernellwp@gmail.com> - 2017-05-27 03:30 +0200
| From | Paolo Bonzini <pbonzini@redhat.com> |
|---|---|
| Date | 2017-05-26 18:00 +0200 |
| Subject | Re: [PATCH] KVM: X86: Fix preempt the preemption timer cancel |
| Message-ID | <tLpOF-7Ks-3@gated-at.bofh.it> |
On 21/05/2017 05:32, Wanpeng Li wrote:
> CPU0 CPU1
>
> vmx_cancel_hv_timer
> vCPU0's vmx->hv_deadline_tsc = -1
>
> preempt occur
>
> clear preemption timer field in CPU1's active vmcs
> vCPU0's apic_timer.hv_timer_in_use = false
> vmx_vcpu_run(vCPU0)
> vmx_arm_hv_timer
> if (vmx->hv_deadline_tsc == -1)
> nothing change
>
> handle_preemption_timer(vCPU0)
> kvm_lapic_expired_hv_timer
> WARN_ON(!apic->lapic_timer.hv_timer_in_use);
I think it's more like this, what do you think?
CPU0 CPU1
preemption timer vmexit
handle_preemption_timer(vCPU0)
kvm_lapic_expired_hv_timer
vmx_cancel_hv_timer
vmx->hv_deadline_tsc = -1
vmcs_clear_bits
/* hv_timer_in_use still true */
sched_out
sched_in
kvm_arch_vcpu_load
vmx_set_hv_timer
write vmx->hv_deadline_tsc
vmcs_set_bits
/* back in kvm_lapic_expired_hv_timer */
hv_timer_in_use = false
...
vmx_vcpu_run
vmx_arm_hv_run
write preemption timer deadline
spurious preemption timer vmexit
handle_preemption_timer(vCPU0)
kvm_lapic_expired_hv_timer
WARN_ON(!apic->lapic_timer.hv_timer_in_use);
Thanks,
Paolo
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| From | Wanpeng Li <kernellwp@gmail.com> |
|---|---|
| Date | 2017-05-27 03:30 +0200 |
| Message-ID | <tLyIj-4Vw-71@gated-at.bofh.it> |
| In reply to | #1651445 |
2017-05-26 23:57 GMT+08:00 Paolo Bonzini <pbonzini@redhat.com>: > > > On 21/05/2017 05:32, Wanpeng Li wrote: >> CPU0 CPU1 >> >> vmx_cancel_hv_timer >> vCPU0's vmx->hv_deadline_tsc = -1 >> >> preempt occur >> >> clear preemption timer field in CPU1's active vmcs >> vCPU0's apic_timer.hv_timer_in_use = false >> vmx_vcpu_run(vCPU0) >> vmx_arm_hv_timer >> if (vmx->hv_deadline_tsc == -1) >> nothing change >> >> handle_preemption_timer(vCPU0) >> kvm_lapic_expired_hv_timer >> WARN_ON(!apic->lapic_timer.hv_timer_in_use); > > > I think it's more like this, what do you think? > > CPU0 CPU1 > > preemption timer vmexit > handle_preemption_timer(vCPU0) > kvm_lapic_expired_hv_timer > vmx_cancel_hv_timer > vmx->hv_deadline_tsc = -1 > vmcs_clear_bits > /* hv_timer_in_use still true */ > sched_out > sched_in > kvm_arch_vcpu_load > vmx_set_hv_timer > write vmx->hv_deadline_tsc > vmcs_set_bits > /* back in kvm_lapic_expired_hv_timer */ > hv_timer_in_use = false > ... > vmx_vcpu_run > vmx_arm_hv_run > write preemption timer deadline > spurious preemption timer vmexit > handle_preemption_timer(vCPU0) > kvm_lapic_expired_hv_timer > WARN_ON(!apic->lapic_timer.hv_timer_in_use); Looks good to me, thanks for your help, Paolo. :) Regards, Wanpeng Li
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