From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-dev-return-5148-cohuck=redhat.com@lists.oasis-open.org Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 0A125985B20 for ; Sat, 8 Dec 2018 13:35:34 +0000 (UTC) Date: Sat, 8 Dec 2018 21:33:37 +0800 From: Tiwei Bie Message-ID: <20181208133337.GB29772@dpdk-tbie> References: <20181207084842.13133-1-tiwei.bie@intel.com> <20181207084842.13133-3-tiwei.bie@intel.com> <20181207130336-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20181207130336-mutt-send-email-mst@kernel.org> Subject: [virtio-dev] Re: [RFC 2/3] virtio_ring: add VIRTIO_RING_NO_LEGACY To: "Michael S. Tsirkin" Cc: jasowang@redhat.com, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, virtio-dev@lists.oasis-open.org, wexu@redhat.com, jfreimann@redhat.com, maxime.coquelin@redhat.com List-ID: On Fri, Dec 07, 2018 at 01:05:35PM -0500, Michael S. Tsirkin wrote: > On Fri, Dec 07, 2018 at 04:48:41PM +0800, Tiwei Bie wrote: > > Introduce VIRTIO_RING_NO_LEGACY to support disabling legacy > > macros and layout definitions. > > > > Suggested-by: Michael S. Tsirkin > > Signed-off-by: Tiwei Bie > > --- > > VRING_AVAIL_ALIGN_SIZE, VRING_USED_ALIGN_SIZE and VRING_DESC_ALIGN_SIZE > > are not pre-virtio 1.0, but can also be disabled by VIRTIO_RING_NO_LEGACY > > in this patch, because their names are not consistent with other names. > > Not sure whether this is a good idea. If we want this, we may also want > > to define _SPLIT_ version for them. > > I don't think it's a good idea to have alignment in there - the point of > NO_LEGACY is to help catch bugs not to sanitize coding style IMHO. > > And spec calls "legacy" the 0.X interfaces, let's not muddy the waters. Make sense. Thanks! > > > > > include/uapi/linux/virtio_ring.h | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/include/uapi/linux/virtio_ring.h b/include/uapi/linux/virtio_ring.h > > index 9b0c0d92ab62..192573827850 100644 > > --- a/include/uapi/linux/virtio_ring.h > > +++ b/include/uapi/linux/virtio_ring.h > > @@ -37,6 +37,7 @@ > > #include > > #include > > > > +#ifndef VIRTIO_RING_NO_LEGACY > > /* > > * Notice: unlike other _F_ flags, below flags are defined as shifted > > * values instead of shifts for compatibility. > > @@ -51,6 +52,7 @@ > > #define VRING_USED_F_NO_NOTIFY 1 > > /* Same as VRING_SPLIT_AVAIL_F_NO_INTERRUPT. */ > > #define VRING_AVAIL_F_NO_INTERRUPT 1 > > +#endif /* VIRTIO_RING_NO_LEGACY */ > > > > /* Mark a buffer as continuing via the next field in split ring. */ > > #define VRING_SPLIT_DESC_F_NEXT 0 > > @@ -151,6 +153,7 @@ struct vring { > > struct vring_used *used; > > }; > > > > +#ifndef VIRTIO_RING_NO_LEGACY > > /* Alignment requirements for vring elements. > > * When using pre-virtio 1.0 layout, these fall out naturally. > > */ > > @@ -203,6 +206,7 @@ static inline unsigned vring_size(unsigned int num, unsigned long align) > > + align - 1) & ~(align - 1)) > > + sizeof(__virtio16) * 3 + sizeof(struct vring_used_elem) * num; > > } > > +#endif /* VIRTIO_RING_NO_LEGACY */ > > > > /* The following is used with USED_EVENT_IDX and AVAIL_EVENT_IDX */ > > /* Assuming a given event_idx value from the other side, if > > -- > > 2.17.1 --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org