From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tiwei Bie Subject: [RFC 2/3] virtio_ring: add VIRTIO_RING_NO_LEGACY Date: Fri, 7 Dec 2018 16:48:41 +0800 Message-ID: <20181207084842.13133-3-tiwei.bie@intel.com> References: <20181207084842.13133-1-tiwei.bie@intel.com> Cc: wexu@redhat.com, jfreimann@redhat.com, maxime.coquelin@redhat.com, tiwei.bie@intel.com To: mst@redhat.com, jasowang@redhat.com, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, virtio-dev@lists.oasis-open.org Return-path: In-Reply-To: <20181207084842.13133-1-tiwei.bie@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org 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. 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