linux-kernel - Re: [PATCHv2 2/2] kvm: x86: implement KVM PM-notifier

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Message-ID: <a304706273ff750b4aa8b822606fb03e@kernel.org>
Date:   Sat, 05 Jun 2021 12:27:45 +0100
From:   Marc Zyngier <maz@...nel.org>
To:     Sergey Senozhatsky <senozhatsky@...omium.org>
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Suleiman Souhlal <suleiman@...gle.com>, x86@...nel.org,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCHv2 2/2] kvm: x86: implement KVM PM-notifier

On 2021-06-05 11:48, Sergey Senozhatsky wrote:
> On (21/06/05 10:00), Marc Zyngier wrote:
>> > +static int kvm_arch_suspend_notifier(struct kvm *kvm)
>> > +{
>> > +	struct kvm_vcpu *vcpu;
>> > +	int i, ret;
>> > +
>> > +	mutex_lock(&kvm->lock);
>> > +	kvm_for_each_vcpu(i, vcpu, kvm) {
>> > +		ret = kvm_set_guest_paused(vcpu);
>> > +		if (ret) {
>> > +			pr_err("Failed to pause guest VCPU%d: %d\n",
>> > +			       vcpu->vcpu_id, ret);
>> 
>> how useful the pr_err() is, given that it contains no information
>> that would help identifying which guest failed to pause.
> 
> Do other printk-s contain such info? All I can see so far is
> `#define pr_fmt(fmt) "kvm-guest: " fmt` which doesn't point
> at any particular VM.

Look for kvm_{err,info,debug...} and vcpu_{err,debug...}, all of
which will at least give you a PID. Even x86 uses it.

         M.
-- 
Jazz is not dead. It just smells funny...