From: Tiwei Bie <tiwei.bie@intel.com>
To: mst@redhat.com, virtualization@lists.linux-foundation.org,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Cc: jasowang@redhat.com, wexu@redhat.com, jfreimann@redhat.com,
tiwei.bie@intel.com
Subject: [PATCH RFC 1/2] virtio: introduce packed ring defines
Date: Fri, 23 Feb 2018 19:18:00 +0800 [thread overview]
Message-ID: <20180223111801.15240-2-tiwei.bie@intel.com> (raw)
In-Reply-To: <20180223111801.15240-1-tiwei.bie@intel.com>
Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
---
include/uapi/linux/virtio_config.h | 18 +++++++++-
include/uapi/linux/virtio_ring.h | 68 ++++++++++++++++++++++++++++++++++++++
2 files changed, 85 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h
index 308e2096291f..e3d077ef5207 100644
--- a/include/uapi/linux/virtio_config.h
+++ b/include/uapi/linux/virtio_config.h
@@ -49,7 +49,7 @@
* transport being used (eg. virtio_ring), the rest are per-device feature
* bits. */
#define VIRTIO_TRANSPORT_F_START 28
-#define VIRTIO_TRANSPORT_F_END 34
+#define VIRTIO_TRANSPORT_F_END 37
#ifndef VIRTIO_CONFIG_NO_LEGACY
/* Do we get callbacks when the ring is completely used, even if we've
@@ -71,4 +71,20 @@
* this is for compatibility with legacy systems.
*/
#define VIRTIO_F_IOMMU_PLATFORM 33
+
+/* This feature indicates support for the packed virtqueue layout. */
+#define VIRTIO_F_RING_PACKED 34
+
+/*
+ * This feature indicates that all buffers are used by the device
+ * in the same order in which they have been made available.
+ */
+#define VIRTIO_F_IN_ORDER 35
+
+/*
+ * This feature indicates that drivers pass extra data (besides
+ * identifying the Virtqueue) in their device notifications.
+ */
+#define VIRTIO_F_NOTIFICATION_DATA 36
+
#endif /* _UAPI_LINUX_VIRTIO_CONFIG_H */
diff --git a/include/uapi/linux/virtio_ring.h b/include/uapi/linux/virtio_ring.h
index 6d5d5faa989b..77b1d4aeef72 100644
--- a/include/uapi/linux/virtio_ring.h
+++ b/include/uapi/linux/virtio_ring.h
@@ -44,6 +44,9 @@
/* This means the buffer contains a list of buffer descriptors. */
#define VRING_DESC_F_INDIRECT 4
+#define VRING_DESC_F_AVAIL(b) ((b) << 7)
+#define VRING_DESC_F_USED(b) ((b) << 15)
+
/* The Host uses this in used->flags to advise the Guest: don't kick me when
* you add a buffer. It's unreliable, so it's simply an optimization. Guest
* will still kick if it's out of buffers. */
@@ -104,6 +107,36 @@ struct vring {
struct vring_used *used;
};
+struct vring_packed_desc_event {
+ /* Descriptor Event Offset */
+ __virtio16 desc_event_off : 15,
+ /* Descriptor Event Wrap Counter */
+ desc_event_wrap : 1;
+ /* Descriptor Event Flags */
+ __virtio16 desc_event_flags : 2;
+};
+
+struct vring_packed_desc {
+ /* Buffer Address. */
+ __virtio64 addr;
+ /* Buffer Length. */
+ __virtio32 len;
+ /* Buffer ID. */
+ __virtio16 id;
+ /* The flags depending on descriptor type. */
+ __virtio16 flags;
+};
+
+struct vring_packed {
+ unsigned int num;
+
+ struct vring_packed_desc *desc;
+
+ struct vring_packed_desc_event *driver;
+
+ struct vring_packed_desc_event *device;
+};
+
/* Alignment requirements for vring elements.
* When using pre-virtio 1.0 layout, these fall out naturally.
*/
@@ -171,4 +204,39 @@ static inline int vring_need_event(__u16 event_idx, __u16 new_idx, __u16 old)
return (__u16)(new_idx - event_idx - 1) < (__u16)(new_idx - old);
}
+/* The standard layout for the packed ring is a continuous chunk of memory
+ * which looks like this.
+ *
+ * struct vring_packed
+ * {
+ * // The actual descriptors (16 bytes each)
+ * struct vring_packed_desc desc[num];
+ *
+ * // Padding to the next align boundary.
+ * char pad[];
+ *
+ * // Driver Event Suppression
+ * struct vring_packed_desc_event driver;
+ *
+ * // Device Event Suppression
+ * struct vring_packed_desc_event device;
+ * };
+ */
+
+static inline void vring_packed_init(struct vring_packed *vr, unsigned int num,
+ void *p, unsigned long align)
+{
+ vr->num = num;
+ vr->desc = p;
+ vr->driver = (void *)(((uintptr_t)p + sizeof(struct vring_packed_desc)
+ * num + align - 1) & ~(align - 1));
+ vr->device = vr->driver + 1;
+}
+
+static inline unsigned vring_packed_size(unsigned int num, unsigned long align)
+{
+ return ((sizeof(struct vring_packed_desc) * num + align - 1)
+ & ~(align - 1)) + sizeof(struct vring_packed_desc_event) * 2;
+}
+
#endif /* _UAPI_LINUX_VIRTIO_RING_H */
--
2.14.1
next prev parent reply other threads:[~2018-02-23 11:19 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-23 11:17 [PATCH RFC 0/2] Packed ring for virtio Tiwei Bie
2018-02-23 11:18 ` Tiwei Bie [this message]
2018-02-27 8:54 ` [PATCH RFC 1/2] virtio: introduce packed ring defines Jens Freimann
2018-02-27 9:18 ` Jens Freimann
2018-02-27 12:01 ` Tiwei Bie
2018-02-27 20:28 ` Michael S. Tsirkin
2018-02-27 9:26 ` David Laight
2018-02-27 11:31 ` Tiwei Bie
2018-02-23 11:18 ` [PATCH RFC 2/2] virtio_ring: support packed ring Tiwei Bie
2018-03-16 4:03 ` Jason Wang
2018-03-16 6:10 ` Tiwei Bie
2018-03-16 6:44 ` Jason Wang
2018-03-16 7:40 ` Tiwei Bie
2018-03-16 8:34 ` Jason Wang
2018-03-16 10:04 ` Tiwei Bie
2018-03-16 11:36 ` Jason Wang
2018-03-16 14:30 ` Michael S. Tsirkin
2018-03-21 7:35 ` Tiwei Bie
2018-03-21 7:30 ` Tiwei Bie
-- strict thread matches above, loose matches on Subject: below --
2018-02-14 2:37 [PATCH RFC 0/2] Packed ring for vhost Jason Wang
2018-02-14 2:37 ` [PATCH RFC 1/2] virtio: introduce packed ring defines Jason Wang
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