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From:   Jim Mattson <jmattson@google.com>
Date:   Tue, 15 May 2018 14:56:41 -0700
Message-ID: <CALMp9eT5aD0tjdTzTABo5a0aEtB52bZ7_-PCTF35Tikf8Q-vDg@mail.gmail.com>
Subject: Re: [PATCH 2/3] KVM: X86: Allow userspace to disable ioport intercept
To:     Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc:     Wanpeng Li <kernellwp@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>,
        kvm list <kvm@vger.kernel.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= <rkrcmar@redhat.com>,
        Tim Shearer <tshearer@advaoptical.com>,
        Liran Alon <liran.alon@oracle.com>
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I'd prefer to let the kvm module have the final say as to whether or
not to allow userspace to do this.

On Fri, May 11, 2018 at 8:43 AM, Konrad Rzeszutek Wilk
<konrad.wilk@oracle.com> wrote:
> On Fri, May 11, 2018 at 11:42:46AM -0400, Konrad Rzeszutek Wilk wrote:
>> On Mon, Apr 16, 2018 at 10:46:01PM -0700, Wanpeng Li wrote:
>> > From: Wanpeng Li <wanpengli@tencent.com>
>> >
>> > Allow to disable ioport intercept by userspace.
>> >
>> > Cc: Paolo Bonzini <pbonzini@redhat.com>
>> > Cc: Radim Kr=C4=8Dm=C3=A1=C5=99 <rkrcmar@redhat.com>
>> > Cc: Tim Shearer <tshearer@advaoptical.com>
>> > Cc: Liran Alon <liran.alon@oracle.com>
>> > Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
>> > ---
>> >  Documentation/virtual/kvm/api.txt | 11 +++++++++++
>> >  arch/x86/include/asm/kvm_host.h   |  2 ++
>> >  arch/x86/kvm/x86.c                |  5 +++++
>> >  include/uapi/linux/kvm.h          |  1 +
>> >  4 files changed, 19 insertions(+)
>> >
>> > diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual=
/kvm/api.txt
>> > index 1c7958b..3d0488e 100644
>> > --- a/Documentation/virtual/kvm/api.txt
>> > +++ b/Documentation/virtual/kvm/api.txt
>> > @@ -4378,6 +4378,17 @@ all such vmexits.
>> >
>> >  Do not enable KVM_FEATURE_PV_UNHALT if you disable HLT exits.
>> >
>> > +7.14 KVM_CAP_IOPORT_DISABLE_INTERCEPT
>> > +
>> > +Architectures: x86
>
> And to be exact: Intel only..