From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Dr. David Alan Gilbert" Subject: Re: virtq questions Date: Wed, 2 Oct 2019 15:52:51 +0100 Message-ID: <20191002145251.GD2710@work-vm> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Miklos Szeredi Cc: Stefan Hajnoczi , Vivek Goyal , virtualization@lists.linux-foundation.org List-Id: virtualization@lists.linuxfoundation.org * Miklos Szeredi (miklos@szeredi.hu) wrote: > Looking at the ugly retry logic in virtiofs and have some questions. > First one is, where do these features come from: > > VIRTIO_F_RING_PACKED > VIRTIO_RING_F_INDIRECT_DESC > > I see that in virtiofs "packed" is off and "indirect" is on. Is this > guaranteed? I think the xdindirect is coming from qemu's hw/virtio/virtio.h DEFINE_VIRTIO_COMMON_FEATURES which has: DEFINE_PROP_BIT64("indirect_desc", _state, _field, \ VIRTIO_RING_F_INDIRECT_DESC, true), \ Dave > Thanks, > Miklos -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK