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SubjectRe: [PATCH RFC 1/2] virtio: introduce packed ring defines
On Fri, Feb 23, 2018 at 07:18:00PM +0800, Tiwei Bie wrote:
>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

Spec says VIRTIO_F_PACKED_RING not RING_PACKED
>+
>+/*
>+ * 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;
>+};

Where would the virtqueue number go in driver notifications?

regards,
Jens

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