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To:     Jason Gunthorpe <jgg@nvidia.com>,
        "Tian, Kevin" <kevin.tian@intel.com>
Cc:     Alex Williamson <alex.williamson@redhat.com>,
        Jean-Philippe Brucker <jean-philippe@linaro.org>,
        "Jiang, Dave" <dave.jiang@intel.com>,
        "Raj, Ashok" <ashok.raj@intel.com>,
        "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Robin Murphy <robin.murphy@arm.com>,
        LKML <linux-kernel@vger.kernel.org>,
        "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>,
        David Gibson <david@gibson.dropbear.id.au>,
        Kirti Wankhede <kwankhede@nvidia.com>,
        David Woodhouse <dwmw2@infradead.org>,
        Jason Wang <jasowang@redhat.com>
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From:   Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [RFC] /dev/ioasid uAPI proposal
Message-ID: <086ca28f-42e5-a432-8bef-ac47a0a6df45@redhat.com>
Date:   Wed, 9 Jun 2021 14:46:05 +0200
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On 09/06/21 13:57, Jason Gunthorpe wrote:
> On Wed, Jun 09, 2021 at 02:49:32AM +0000, Tian, Kevin wrote:
> 
>> Last unclosed open. Jason, you dislike symbol_get in this contract per
>> earlier comment. As Alex explained, looks it's more about module
>> dependency which is orthogonal to how this contract is designed. What
>> is your opinion now?
> 
> Generally when you see symbol_get like this it suggests something is
> wrong in the layering..
> 
> Why shouldn't kvm have a normal module dependency on drivers/iommu?

It allows KVM to load even if there's an "install /bin/false" for vfio 
(typically used together with the blacklist directive) in modprobe.conf. 
  This rationale should apply to iommu as well.

Paolo