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Re: [Qemu-devel] [ RFC Patch v4 1/3] virtio-net rsc: add a new host offl
From: |
Jason Wang |
Subject: |
Re: [Qemu-devel] [ RFC Patch v4 1/3] virtio-net rsc: add a new host offload(rsc) feature bit |
Date: |
Tue, 5 Apr 2016 10:05:17 +0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 |
On 04/04/2016 03:25 AM, address@hidden wrote:
> From: Wei Xu <address@hidden>
>
> A new feature bit 'VIRTIO_NET_F_GUEST_RSC' is introduced to support WHQL
> Receive-Segment-Offload test, this feature will coalesce tcp packets in
> IPv4/6 for userspace virtio-net driver.
>
> This feature can be enabled either by 'ACK' the feature when loading
> the driver in the guest, or by sending the
> 'VIRTIO_NET_CTRL_GUEST_OFFLOADS_SET'
> command to the host via control queue.
>
> Signed-off-by: Wei Xu <address@hidden>
> ---
> hw/net/virtio-net.c | 29
> +++++++++++++++++++++++++++--
> include/standard-headers/linux/virtio_net.h | 1 +
> 2 files changed, 28 insertions(+), 2 deletions(-)
>
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 5798f87..bd91a4b 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -537,6 +537,7 @@ static uint64_t virtio_net_get_features(VirtIODevice
> *vdev, uint64_t features,
> virtio_clear_feature(&features, VIRTIO_NET_F_GUEST_TSO4);
> virtio_clear_feature(&features, VIRTIO_NET_F_GUEST_TSO6);
> virtio_clear_feature(&features, VIRTIO_NET_F_GUEST_ECN);
> + virtio_clear_feature(&features, VIRTIO_NET_F_GUEST_RSC);
Several questions here:
- I think RSC should work even without vnet_hdr?
- Need we differentiate ipv4 and ipv6 like TSO here?
- And looks like this patch should be squash to following patches.
> }
>
> if (!peer_has_vnet_hdr(n) || !peer_has_ufo(n)) {
> @@ -582,7 +583,8 @@ static uint64_t
> virtio_net_guest_offloads_by_features(uint32_t features)
> (1ULL << VIRTIO_NET_F_GUEST_TSO4) |
> (1ULL << VIRTIO_NET_F_GUEST_TSO6) |
> (1ULL << VIRTIO_NET_F_GUEST_ECN) |
> - (1ULL << VIRTIO_NET_F_GUEST_UFO);
> + (1ULL << VIRTIO_NET_F_GUEST_UFO) |
> + (1ULL << VIRTIO_NET_F_GUEST_RSC);
Looks like this is unnecessary since we won't set peer offload based on
GUEST_RSC.
>
> return guest_offloads_mask & features;
> }
> @@ -1089,7 +1091,8 @@ static int receive_filter(VirtIONet *n, const uint8_t
> *buf, int size)
> return 0;
> }
>
> -static ssize_t virtio_net_receive(NetClientState *nc, const uint8_t *buf,
> size_t size)
> +static ssize_t virtio_net_do_receive(NetClientState *nc,
> + const uint8_t *buf, size_t size)
> {
> VirtIONet *n = qemu_get_nic_opaque(nc);
> VirtIONetQueue *q = virtio_net_get_subqueue(nc);
> @@ -1685,6 +1688,26 @@ static int virtio_net_load_device(VirtIODevice *vdev,
> QEMUFile *f,
> return 0;
> }
>
> +
> +static ssize_t virtio_net_rsc_receive(NetClientState *nc,
> + const uint8_t *buf, size_t size)
> +{
> + return virtio_net_do_receive(nc, buf, size);
> +}
> +
> +static ssize_t virtio_net_receive(NetClientState *nc,
> + const uint8_t *buf, size_t size)
> +{
> + VirtIONet *n;
> +
> + n = qemu_get_nic_opaque(nc);
> + if (n->curr_guest_offloads & VIRTIO_NET_F_GUEST_RSC) {
> + return virtio_net_rsc_receive(nc, buf, size);
> + } else {
> + return virtio_net_do_receive(nc, buf, size);
> + }
> +}
The changes here looks odd since it did nothing. Like I've mentioned,
better merge the patch into following ones.
> +
> static NetClientInfo net_virtio_info = {
> .type = NET_CLIENT_OPTIONS_KIND_NIC,
> .size = sizeof(NICState),
> @@ -1909,6 +1932,8 @@ static Property virtio_net_properties[] = {
> TX_TIMER_INTERVAL),
> DEFINE_PROP_INT32("x-txburst", VirtIONet, net_conf.txburst, TX_BURST),
> DEFINE_PROP_STRING("tx", VirtIONet, net_conf.tx),
> + DEFINE_PROP_BIT("guest_rsc", VirtIONet, host_features,
> + VIRTIO_NET_F_GUEST_RSC, true),
Need to compat the bit for old machine type to unbreak migration I believe?
Btw, also need a patch for virtio spec.
Thanks
> DEFINE_PROP_END_OF_LIST(),
> };
>
> diff --git a/include/standard-headers/linux/virtio_net.h
> b/include/standard-headers/linux/virtio_net.h
> index a78f33e..5b95762 100644
> --- a/include/standard-headers/linux/virtio_net.h
> +++ b/include/standard-headers/linux/virtio_net.h
> @@ -55,6 +55,7 @@
> #define VIRTIO_NET_F_MQ 22 /* Device supports Receive Flow
> * Steering */
> #define VIRTIO_NET_F_CTRL_MAC_ADDR 23 /* Set MAC address */
> +#define VIRTIO_NET_F_GUEST_RSC 24 /* Guest can coalesce tcp packets */
>
> #ifndef VIRTIO_NET_NO_LEGACY
> #define VIRTIO_NET_F_GSO 6 /* Host handles pkts w/ any GSO type */
Re: [Qemu-devel] [ RFC Patch v4 2/3] virtio-net rsc: support coalescing ipv4 tcp traffic, Michael S. Tsirkin, 2016/04/12
[Qemu-devel] [ RFC Patch v4 3/3] virtio-net rsc: support coalescing ipv6 tcp traffic, wexu, 2016/04/03