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([2a01:e0a:59e:9d80:527b:9dff:feef:3874]) by smtp.gmail.com with ESMTPSA id x85-20020a376358000000b0074a28c33df7sm343465qkb.84.2023.04.06.02.46.57 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 06 Apr 2023 02:47:00 -0700 (PDT) Message-ID: <8fb5a0b3-39c6-e924-847d-6545fcc44c08@redhat.com> Date: Thu, 6 Apr 2023 11:46:55 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.5.0 To: Yi Liu , alex.williamson@redhat.com, jgg@nvidia.com, kevin.tian@intel.com References: <20230401151833.124749-1-yi.l.liu@intel.com> <20230401151833.124749-7-yi.l.liu@intel.com> From: Eric Auger In-Reply-To: <20230401151833.124749-7-yi.l.liu@intel.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Intel-gfx] [PATCH v9 06/25] kvm/vfio: Accept vfio device file from userspace X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: eric.auger@redhat.com Cc: linux-s390@vger.kernel.org, yi.y.sun@linux.intel.com, kvm@vger.kernel.org, mjrosato@linux.ibm.com, intel-gvt-dev@lists.freedesktop.org, joro@8bytes.org, cohuck@redhat.com, xudong.hao@intel.com, peterx@redhat.com, yan.y.zhao@intel.com, terrence.xu@intel.com, nicolinc@nvidia.com, shameerali.kolothum.thodi@huawei.com, suravee.suthikulpanit@amd.com, intel-gfx@lists.freedesktop.org, chao.p.peng@linux.intel.com, lulu@redhat.com, robin.murphy@arm.com, jasowang@redhat.com, yanting.jiang@intel.com Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Hi Yi, On 4/1/23 17:18, Yi Liu wrote: > This defines KVM_DEV_VFIO_FILE* and make alias with KVM_DEV_VFIO_GROUP*. > Old userspace uses KVM_DEV_VFIO_GROUP* works as well. > > Reviewed-by: Jason Gunthorpe > Reviewed-by: Kevin Tian > Tested-by: Terrence Xu > Tested-by: Nicolin Chen > Tested-by: Matthew Rosato > Tested-by: Yanting Jiang > Signed-off-by: Yi Liu > --- > Documentation/virt/kvm/devices/vfio.rst | 53 +++++++++++++++++-------- > include/uapi/linux/kvm.h | 16 ++++++-- > virt/kvm/vfio.c | 16 ++++---- > 3 files changed, 56 insertions(+), 29 deletions(-) > > diff --git a/Documentation/virt/kvm/devices/vfio.rst b/Documentation/virt/kvm/devices/vfio.rst > index 79b6811bb4f3..277d727ec1a2 100644 > --- a/Documentation/virt/kvm/devices/vfio.rst > +++ b/Documentation/virt/kvm/devices/vfio.rst > @@ -9,24 +9,38 @@ Device types supported: > - KVM_DEV_TYPE_VFIO > > Only one VFIO instance may be created per VM. The created device > -tracks VFIO groups in use by the VM and features of those groups > -important to the correctness and acceleration of the VM. As groups > -are enabled and disabled for use by the VM, KVM should be updated > -about their presence. When registered with KVM, a reference to the > -VFIO-group is held by KVM. > +tracks VFIO files (group or device) in use by the VM and features > +of those groups/devices important to the correctness and acceleration > +of the VM. As groups/devices are enabled and disabled for use by the > +VM, KVM should be updated about their presence. When registered with > +KVM, a reference to the VFIO file is held by KVM. > > Groups: > - KVM_DEV_VFIO_GROUP > - > -KVM_DEV_VFIO_GROUP attributes: > - KVM_DEV_VFIO_GROUP_ADD: Add a VFIO group to VFIO-KVM device tracking > - kvm_device_attr.addr points to an int32_t file descriptor > - for the VFIO group. > - KVM_DEV_VFIO_GROUP_DEL: Remove a VFIO group from VFIO-KVM device tracking > - kvm_device_attr.addr points to an int32_t file descriptor > - for the VFIO group. > - KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: attaches a guest visible TCE table > + KVM_DEV_VFIO_FILE > + alias: KVM_DEV_VFIO_GROUP > + > +KVM_DEV_VFIO_FILE attributes: > + KVM_DEV_VFIO_FILE_ADD: Add a VFIO file (group/device) to VFIO-KVM device > + tracking > + > + alias: KVM_DEV_VFIO_GROUP_ADD > + > + kvm_device_attr.addr points to an int32_t file descriptor for the > + VFIO file. > + > + KVM_DEV_VFIO_FILE_DEL: Remove a VFIO file (group/device) from VFIO-KVM > + device tracking > + > + alias: KVM_DEV_VFIO_GROUP_DEL > + > + kvm_device_attr.addr points to an int32_t file descriptor for the > + VFIO file. > + > + KVM_DEV_VFIO_FILE_SET_SPAPR_TCE: attaches a guest visible TCE table > allocated by sPAPR KVM. > + > + alias: KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE > + > kvm_device_attr.addr points to a struct:: > > struct kvm_vfio_spapr_tce { > @@ -40,9 +54,14 @@ KVM_DEV_VFIO_GROUP attributes: > - @tablefd is a file descriptor for a TCE table allocated via > KVM_CREATE_SPAPR_TCE. > > + only accepts vfio group file as SPAPR has no iommufd support So then what is the point of introducing KVM_DEV_VFIO_FILE_SET_SPAPR_TCE at this stage? I think would have separated the Groups: KVM_DEV_VFIO_FILE alias: KVM_DEV_VFIO_GROUP KVM_DEV_VFIO_FILE attributes: KVM_DEV_VFIO_FILE_ADD: Add a VFIO file (group/device) to VFIO-KVM device tracking kvm_device_attr.addr points to an int32_t file descriptor for the VFIO file. KVM_DEV_VFIO_FILE_DEL: Remove a VFIO file (group/device) from VFIO-KVM device tracking kvm_device_attr.addr points to an int32_t file descriptor for the VFIO file. KVM_DEV_VFIO_GROUP (legacy kvm device group restricted to the handling of VFIO group fd) KVM_DEV_VFIO_GROUP_ADD: same as KVM_DEV_VFIO_FILE_ADD for group fd only KVM_DEV_VFIO_GROUP_DEL: same as KVM_DEV_VFIO_FILE_DEL for group fd only KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: attaches a guest visible TCE table allocated by sPAPR KVM. kvm_device_attr.addr points to a struct:: struct kvm_vfio_spapr_tce { __s32 groupfd; __s32 tablefd; }; where: - @groupfd is a file descriptor for a VFIO group; - @tablefd is a file descriptor for a TCE table allocated via KVM_CREATE_SPAPR_TCE. You don't say anything about potential restriction, ie. what if the user calls KVM_DEV_VFIO_FILE with device fds while it has been using legacy container/group API? Thanks Eric > + > :: > > -The GROUP_ADD operation above should be invoked prior to accessing the > +The FILE/GROUP_ADD operation above should be invoked prior to accessing the > device file descriptor via VFIO_GROUP_GET_DEVICE_FD in order to support > drivers which require a kvm pointer to be set in their .open_device() > -callback. > +callback. It is the same for device file descriptor via character device > +open which gets device access via VFIO_DEVICE_BIND_IOMMUFD. For such file > +descriptors, FILE_ADD should be invoked before VFIO_DEVICE_BIND_IOMMUFD > +to support the drivers mentioned in prior sentence as well. > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h > index d77aef872a0a..a8eeca70a498 100644 > --- a/include/uapi/linux/kvm.h > +++ b/include/uapi/linux/kvm.h > @@ -1410,10 +1410,18 @@ struct kvm_device_attr { > __u64 addr; /* userspace address of attr data */ > }; > > -#define KVM_DEV_VFIO_GROUP 1 > -#define KVM_DEV_VFIO_GROUP_ADD 1 > -#define KVM_DEV_VFIO_GROUP_DEL 2 > -#define KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE 3 > +#define KVM_DEV_VFIO_FILE 1 > + > +#define KVM_DEV_VFIO_FILE_ADD 1 > +#define KVM_DEV_VFIO_FILE_DEL 2 > +#define KVM_DEV_VFIO_FILE_SET_SPAPR_TCE 3 > + > +/* KVM_DEV_VFIO_GROUP aliases are for compile time uapi compatibility */ > +#define KVM_DEV_VFIO_GROUP KVM_DEV_VFIO_FILE > + > +#define KVM_DEV_VFIO_GROUP_ADD KVM_DEV_VFIO_FILE_ADD > +#define KVM_DEV_VFIO_GROUP_DEL KVM_DEV_VFIO_FILE_DEL > +#define KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE KVM_DEV_VFIO_FILE_SET_SPAPR_TCE > > enum kvm_device_type { > KVM_DEV_TYPE_FSL_MPIC_20 = 1, > diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c > index 857d6ba349e1..d869913baafd 100644 > --- a/virt/kvm/vfio.c > +++ b/virt/kvm/vfio.c > @@ -286,18 +286,18 @@ static int kvm_vfio_set_file(struct kvm_device *dev, long attr, > int32_t fd; > > switch (attr) { > - case KVM_DEV_VFIO_GROUP_ADD: > + case KVM_DEV_VFIO_FILE_ADD: > if (get_user(fd, argp)) > return -EFAULT; > return kvm_vfio_file_add(dev, fd); > > - case KVM_DEV_VFIO_GROUP_DEL: > + case KVM_DEV_VFIO_FILE_DEL: > if (get_user(fd, argp)) > return -EFAULT; > return kvm_vfio_file_del(dev, fd); > > #ifdef CONFIG_SPAPR_TCE_IOMMU > - case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: > + case KVM_DEV_VFIO_FILE_SET_SPAPR_TCE: > return kvm_vfio_file_set_spapr_tce(dev, arg); > #endif > } > @@ -309,7 +309,7 @@ static int kvm_vfio_set_attr(struct kvm_device *dev, > struct kvm_device_attr *attr) > { > switch (attr->group) { > - case KVM_DEV_VFIO_GROUP: > + case KVM_DEV_VFIO_FILE: > return kvm_vfio_set_file(dev, attr->attr, > u64_to_user_ptr(attr->addr)); > } > @@ -321,12 +321,12 @@ static int kvm_vfio_has_attr(struct kvm_device *dev, > struct kvm_device_attr *attr) > { > switch (attr->group) { > - case KVM_DEV_VFIO_GROUP: > + case KVM_DEV_VFIO_FILE: > switch (attr->attr) { > - case KVM_DEV_VFIO_GROUP_ADD: > - case KVM_DEV_VFIO_GROUP_DEL: > + case KVM_DEV_VFIO_FILE_ADD: > + case KVM_DEV_VFIO_FILE_DEL: > #ifdef CONFIG_SPAPR_TCE_IOMMU > - case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: > + case KVM_DEV_VFIO_FILE_SET_SPAPR_TCE: > #endif > return 0; > }