Messages in this thread | | | Subject | Re: [PATCH net-next 6/8] virtio: introduce packed ring defines | From | Jason Wang <> | Date | Wed, 4 Jul 2018 13:26:24 +0800 |
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On 2018年07月04日 12:48, Tiwei Bie wrote: > On Tue, Jul 03, 2018 at 01:38:02PM +0800, Jason Wang wrote: >> Signed-off-by: Jason Wang <jasowang@redhat.com> >> --- >> include/uapi/linux/virtio_config.h | 2 ++ >> include/uapi/linux/virtio_ring.h | 32 ++++++++++++++++++++++++++++++++ >> 2 files changed, 34 insertions(+) >> >> diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h >> index 449132c..947f6a3 100644 >> --- a/include/uapi/linux/virtio_config.h >> +++ b/include/uapi/linux/virtio_config.h >> @@ -75,6 +75,8 @@ >> */ >> #define VIRTIO_F_IOMMU_PLATFORM 33 >> >> +#define VIRTIO_F_RING_PACKED 34 > It's better to add some comments for this macro.
Ok.
> >> + >> /* >> * Does the device support Single Root I/O Virtualization? >> */ >> diff --git a/include/uapi/linux/virtio_ring.h b/include/uapi/linux/virtio_ring.h >> index 6d5d5fa..71c7a46 100644 >> --- a/include/uapi/linux/virtio_ring.h >> +++ b/include/uapi/linux/virtio_ring.h >> @@ -43,6 +43,8 @@ >> #define VRING_DESC_F_WRITE 2 >> /* This means the buffer contains a list of buffer descriptors. */ >> #define VRING_DESC_F_INDIRECT 4 >> +#define VRING_DESC_F_AVAIL 7 > It's better to use tab between VRING_DESC_F_AVAIL and 7.
Let me fix.
> >> +#define VRING_DESC_F_USED 15 > Maybe it's better to define VRING_DESC_F_AVAIL and > VRING_DESC_F_USED as (1 << 7) and (1 << 15) or something > similar to make them consistent with VRING_DESC_F_NEXT > (1 << 0), VRING_DESC_F_WRITE (1 << 1) and > VRING_DESC_F_INDIRECT (1 << 2).
Ok.
> > I plan to define below macros in virtio_ring.c: > > #define _VRING_DESC_F_AVAIL(b) ((__u16)(b) << 7) > #define _VRING_DESC_F_USED(b) ((__u16)(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 >> @@ -62,6 +64,36 @@ >> * at the end of the used ring. Guest should ignore the used->flags field. */ >> #define VIRTIO_RING_F_EVENT_IDX 29 >> >> +struct vring_desc_packed { > We may have other related types named as: > > struct vring_packed; > struct vring_packed_desc_event; > > So maybe it's better to name this type as: > > struct vring_packed_desc;
Yes.
> >> + /* Buffer Address. */ >> + __virtio64 addr; >> + /* Buffer Length. */ >> + __virtio32 len; >> + /* Buffer ID. */ >> + __virtio16 id; >> + /* The flags depending on descriptor type. */ >> + __virtio16 flags; >> +}; >> + >> +/* Enable events */ >> +#define RING_EVENT_FLAGS_ENABLE 0x0 >> +/* Disable events */ >> +#define RING_EVENT_FLAGS_DISABLE 0x1 >> +/* >> + * Enable events for a specific descriptor >> + * (as specified by Descriptor Ring Change Event Offset/Wrap Counter). >> + * Only valid if VIRTIO_F_RING_EVENT_IDX has been negotiated. >> + */ >> +#define RING_EVENT_FLAGS_DESC 0x2 > For above three macros, maybe it's better to name > them as: > > VRING_EVENT_FLAGS_ENABLE > VRING_EVENT_FLAGS_DISABLE > VRING_EVENT_FLAGS_DESC > > or > > VRING_EVENT_F_ENABLE > VRING_EVENT_F_DISABLE > VRING_EVENT_F_DESC > > VRING_EVENT_F_* will be more consistent with > VIRTIO_F_*, VRING_DESC_F_*, etc
True. Let me fix above in next version.
Thanks
>> +/* The value 0x3 is reserved */ >> + >> +struct vring_packed_desc_event { >> + /* Descriptor Ring Change Event Offset and Wrap Counter */ >> + __virtio16 off_wrap; >> + /* Descriptor Ring Change Event Flags */ >> + __virtio16 flags; >> +}; >> + >> /* Virtio ring descriptors: 16 bytes. These can chain together via "next". */ >> struct vring_desc { >> /* Address (guest-physical). */ >> -- >> 2.7.4 >>
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