From: Marcelo Tosatti <mtosatti@redhat.com>
To: Avi Kivity <avi@qumranet.com>
Cc: kvm-devel <kvm@vger.kernel.org>
Subject: Re: KVM: x86: do not execute guest code if vcpu not runnable
Date: Sat, 19 Jul 2008 20:41:04 -0300 [thread overview]
Message-ID: <20080719234104.GA10435@dmt.cnet> (raw)
In-Reply-To: <20080719181143.GA27283@dmt.cnet>
On Sat, Jul 19, 2008 at 03:11:44PM -0300, Marcelo Tosatti wrote:
>
> If a vcpu has been offlined, or not initialized at all, signals
> requesting userspace work to be performed will result in KVM attempting
> to re-entry guest mode.
>
> Problem is that the in-kernel irqchip emulation happily executes HALTED
> state vcpu's. This breaks "savevm" on Windows SMP installation, for
> example.
>
> Also, setting the mpstate to runnable when setting an IRQ via
> pic_irq_request / kvm_apic_set_irq is necessary due to this check on
> emulate_halt:
>
> kvm_vcpu_block(vcpu);
> down_read(&vcpu->kvm->slots_lock);
> if (vcpu->arch.mp_state != KVM_MP_STATE_RUNNABLE)
> return -EINTR;
>
> Otherwise the vcpu will return to userspace needlessly.
Scratch this, burns 100% CPU.
prev parent reply other threads:[~2008-07-19 23:41 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-19 18:11 KVM: x86: do not execute guest code if vcpu not runnable Marcelo Tosatti
2008-07-19 23:41 ` Marcelo Tosatti [this message]
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