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([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id k12sm6167589wmr.2.2021.06.09.05.46.08 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 09 Jun 2021 05:46:09 -0700 (PDT) To: Jason Gunthorpe , "Tian, Kevin" Cc: Alex Williamson , Jean-Philippe Brucker , "Jiang, Dave" , "Raj, Ashok" , "kvm@vger.kernel.org" , Jonathan Corbet , Robin Murphy , LKML , "iommu@lists.linux-foundation.org" , David Gibson , Kirti Wankhede , David Woodhouse , Jason Wang References: <20210604160336.GA414156@nvidia.com> <2c62b5c7-582a-c710-0436-4ac5e8fd8b39@redhat.com> <20210604172207.GT1002214@nvidia.com> <2d1ad075-bec6-bfb9-ce71-ed873795e973@redhat.com> <20210607175926.GJ1002214@nvidia.com> <20210608131547.GE1002214@nvidia.com> <89d30977-119c-49f3-3bf6-d3f7104e07d8@redhat.com> <20210608124700.7b9aa5a6.alex.williamson@redhat.com> <20210609115759.GY1002214@nvidia.com> From: Paolo Bonzini 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 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <20210609115759.GY1002214@nvidia.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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