[dpdk-dev] [PATCH v3 02/21] net/virtio: vring init for packed queues
Jens Freimann
jfreimann at redhat.com
Thu Apr 5 17:16:34 CEST 2018
On Thu, Apr 05, 2018 at 10:22:28PM +0800, Tiwei Bie wrote:
>On Thu, Apr 05, 2018 at 12:10:12PM +0200, Jens Freimann wrote:
>> Add and initialize descriptor data structures.
>>
>> Signed-off-by: Jens Freimann <jfreimann at redhat.com>
>> ---
>[...]
>> diff --git a/drivers/net/virtio/virtio_ring.h b/drivers/net/virtio/virtio_ring.h
>> index 9e3c2a015..1bd7ba98e 100644
>> --- a/drivers/net/virtio/virtio_ring.h
>> +++ b/drivers/net/virtio/virtio_ring.h
>> @@ -9,6 +9,7 @@
>>
>> #include <rte_common.h>
>>
>> +
>
>There is no need to add this empty line.
>
>> /* This marks a buffer as continuing via the next field. */
>> #define VRING_DESC_F_NEXT 1
>> /* This marks a buffer as write-only (otherwise read-only). */
>> @@ -54,11 +55,38 @@ struct vring_used {
>> struct vring_used_elem ring[0];
>> };
>>
>> +/* For support of packed virtqueues in Virtio 1.1 the format of descriptors
>> + * looks like this.
>> + */
>> +struct vring_desc_packed {
>> + uint64_t addr;
>> + uint32_t len;
>> + uint16_t index;
>> + uint16_t flags;
>> +};
>> +
>> +#define RING_EVENT_FLAGS_ENABLE 0x0
>> +#define RING_EVENT_FLAGS_DISABLE 0x1
>> +#define RING_EVENT_FLAGS_DESC 0x2
>> +struct vring_packed_desc_event {
>> + uint16_t desc_event_off_wrap;
>> + uint16_t desc_event_flags;
>> +};
>> +
>> struct vring {
>> unsigned int num;
>> - struct vring_desc *desc;
>> - struct vring_avail *avail;
>> - struct vring_used *used;
>> + union {
>> + struct vring_desc_packed *desc_packed;
>> + struct vring_desc *desc;
>> + };
>> + union {
>> + struct vring_avail *avail;
>> + struct vring_packed_desc_event *driver_event;
>> + };
>> + union {
>> + struct vring_used *used;
>> + struct vring_packed_desc_event *device_event;
>> + };
>> };
>>
>> /* The standard layout for the ring is a continuous chunk of memory which
>> @@ -95,10 +123,16 @@ struct vring {
>> #define vring_avail_event(vr) (*(uint16_t *)&(vr)->used->ring[(vr)->num])
>>
>> static inline size_t
>> -vring_size(unsigned int num, unsigned long align)
>> +vring_size(struct virtio_hw *hw, unsigned int num, unsigned long align)
>> {
>> size_t size;
>>
>> + if (vtpci_packed_queue(hw)) {
>> + size = num * sizeof(struct vring_desc_packed);
>
>I think you need to add paddings based on the alignment.
>
>> + size += 2 * sizeof(struct vring_packed_desc_event);
>> + return size;
>> + }
>> +
>> size = num * sizeof(struct vring_desc);
>> size += sizeof(struct vring_avail) + (num * sizeof(uint16_t));
>> size = RTE_ALIGN_CEIL(size, align);
>> @@ -108,10 +142,19 @@ vring_size(unsigned int num, unsigned long align)
>> }
>>
>> static inline void
>> -vring_init(struct vring *vr, unsigned int num, uint8_t *p,
>> +vring_init(struct virtio_hw *hw, struct vring *vr, unsigned int num, uint8_t *p,
>> unsigned long align)
>> {
>> vr->num = num;
>> + if (vtpci_packed_queue(hw)) {
>> + vr->desc_packed = (struct vring_desc_packed *)p;
>> + vr->driver_event = (struct vring_packed_desc_event *) (p +
>> + num * sizeof(struct vring_desc_packed));
>
>I think paddings are needed here.
I'll align it with RTE_ALIGN_CEIL, like it's done for the used ring
address.
Thanks!
regards,
Jens
>
>> + vr->device_event = (struct vring_packed_desc_event *) (vr->driver_event +
>> + sizeof(struct vring_packed_desc_event));
>> + return;
>> + }
>> +
>> vr->desc = (struct vring_desc *) p;
>> vr->avail = (struct vring_avail *) (p +
>> num * sizeof(struct vring_desc));
>> diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
>> index 14364f356..cc2e7c0f6 100644
>> --- a/drivers/net/virtio/virtqueue.h
>> +++ b/drivers/net/virtio/virtqueue.h
>> @@ -245,6 +245,16 @@ struct virtio_tx_region {
>> __attribute__((__aligned__(16)));
>> };
>>
>> +static inline void
>> +vring_desc_init_packed(struct vring *vr, int n)
>> +{
>> + int i;
>> + for (i = 0; i < n; i++) {
>> + struct vring_desc_packed *desc = &vr->desc_packed[i];
>> + desc->index = i;
>> + }
>> +}
>> +
>> /* Chain all the descriptors in the ring with an END */
>> static inline void
>> vring_desc_init(struct vring_desc *dp, uint16_t n)
>> --
>> 2.14.3
>>
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