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Tsirkin" To: Jason Wang Subject: Re: [RFC 02/10] vhost: add 3 commands for vhost-vdpa Message-ID: <20220105020008-mutt-send-email-mst@kernel.org> References: <20220105005900.860-1-longpeng2@huawei.com> <20220105005900.860-3-longpeng2@huawei.com> MIME-Version: 1.0 In-Reply-To: Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mst@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=170.10.129.124; envelope-from=mst@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.372, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Cornelia Huck , qemu-devel , Yechuan , "Gonglei \(Arei\)" , huangzhichao@huawei.com, Stefan Hajnoczi , pbonzini , "Longpeng\(Mike\)" , Stefano Garzarella Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Jan 05, 2022 at 12:35:53PM +0800, Jason Wang wrote: > On Wed, Jan 5, 2022 at 8:59 AM Longpeng(Mike) wrote: > > > > From: Longpeng > > > > To support generic vdpa deivce, we need add the following ioctls: > > - GET_VECTORS_NUM: the count of vectors that supported > > Does this mean MSI vectors? If yes, it looks like a layer violation: > vhost is transport independent. Well *guest* needs to know how many vectors device supports. I don't think there's a way around that. Do you? Otherwise guests will at best be suboptimal. > And it reveals device implementation > details which block (cross vendor) migration. > > Thanks Not necessarily, userspace can hide this from guest if it wants to, just validate. > > - GET_CONFIG_SIZE: the size of the virtio config space > > - GET_VQS_NUM: the count of virtqueues that exported > > > > Signed-off-by: Longpeng > > --- > > linux-headers/linux/vhost.h | 10 ++++++++++ > > 1 file changed, 10 insertions(+) > > > > diff --git a/linux-headers/linux/vhost.h b/linux-headers/linux/vhost.h > > index c998860d7b..c5edd75d15 100644 > > --- a/linux-headers/linux/vhost.h > > +++ b/linux-headers/linux/vhost.h > > @@ -150,4 +150,14 @@ > > /* Get the valid iova range */ > > #define VHOST_VDPA_GET_IOVA_RANGE _IOR(VHOST_VIRTIO, 0x78, \ > > struct vhost_vdpa_iova_range) > > + > > +/* Get the number of vectors */ > > +#define VHOST_VDPA_GET_VECTORS_NUM _IOR(VHOST_VIRTIO, 0x79, int) > > + > > +/* Get the virtio config size */ > > +#define VHOST_VDPA_GET_CONFIG_SIZE _IOR(VHOST_VIRTIO, 0x80, int) > > + > > +/* Get the number of virtqueues */ > > +#define VHOST_VDPA_GET_VQS_NUM _IOR(VHOST_VIRTIO, 0x81, int) > > + > > #endif > > -- > > 2.23.0 > >