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Subject: Re: [PATCH] kvm: add capability for halt polling
To:     Jim Mattson <jmattson@google.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>
Cc:     Jon Cargille <jcargill@google.com>,
        David Matlack <dmatlack@google.com>,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Joerg Roedel <joro@8bytes.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>,
        the arch/x86 maintainers <x86@kernel.org>,
        kvm list <kvm@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
References: <20200417221446.108733-1-jcargill@google.com>
 <87d083td9f.fsf@vitty.brq.redhat.com>
 <CALMp9eREdS=nfdtvfNhW87G20Tfdwy69Phdbdmo=NzAw_tavzw@mail.gmail.com>
From:   Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <cea84a43-e400-54b9-a6bc-3ad834c17880@redhat.com>
Date:   Thu, 23 Apr 2020 15:09:50 +0200
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On 22/04/20 23:36, Jim Mattson wrote:
>>> +     case KVM_CAP_HALT_POLL: {
>>> +             if (cap->flags || cap->args[0] != (unsigned int)cap->args[0])
>>> +                     return -EINVAL;
>>> +
>>> +             kvm->max_halt_poll_ns = cap->args[0];
>> Is it safe to allow any value from userspace here or would it maybe make
>> sense to only allow [0, global halt_poll_ns]?
> Would that restriction help to get this change accepted?
> 

No, in the sense that I'm applying it already.

Paolo