From: Tiwei Bie <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
Cc: wexu@redhat.com, jfreimann@redhat.com,
maxime.coquelin@redhat.com, tiwei.bie@intel.com
Subject: [RFC 2/3] virtio_ring: add VIRTIO_RING_NO_LEGACY
Date: Fri, 7 Dec 2018 16:48:41 +0800 [thread overview]
Message-ID: <20181207084842.13133-3-tiwei.bie@intel.com> (raw)
In-Reply-To: <20181207084842.13133-1-tiwei.bie@intel.com>
Introduce VIRTIO_RING_NO_LEGACY to support disabling legacy
macros and layout definitions.
Suggested-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
---
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 <linux/types.h>
#include <linux/virtio_types.h>
+#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
next prev parent reply other threads:[~2018-12-07 8:51 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-07 8:48 [RFC 0/3] virtio_ring: define flags as shifts consistently Tiwei Bie
2018-12-07 8:48 ` [RFC 1/3] " Tiwei Bie
2018-12-07 8:48 ` Tiwei Bie [this message]
2018-12-07 18:05 ` [RFC 2/3] virtio_ring: add VIRTIO_RING_NO_LEGACY Michael S. Tsirkin
2018-12-08 13:33 ` Tiwei Bie
2018-12-07 8:48 ` [RFC 3/3] virtio_ring: use new vring flags Tiwei Bie
2018-12-07 18:10 ` Michael S. Tsirkin
2018-12-08 13:47 ` Tiwei Bie
2018-12-09 14:33 ` Michael S. Tsirkin
2018-12-07 18:11 ` [RFC 0/3] virtio_ring: define flags as shifts consistently Michael S. Tsirkin
2018-12-08 13:26 ` Tiwei Bie
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