Hi, Comments inline.
Best Regards, Xiao > -----Original Message----- > From: Jason Wang <jasow...@redhat.com> > Sent: Friday, May 15, 2020 6:09 PM > To: Wang, Xiao W <xiao.w.w...@intel.com>; Maxime Coquelin > <maxime.coque...@redhat.com>; Ye, Xiaolong <xiaolong...@intel.com>; > shah...@mellanox.com; ma...@mellanox.com; amore...@redhat.com; > viachesl...@mellanox.com; dev@dpdk.org > Cc: l...@redhat.com; Xu, Rosen <rosen...@intel.com> > Subject: Re: [PATCH 3/9] vdpa/ifc: add support to vDPA queue enable > > > On 2020/5/15 下午5:42, Wang, Xiao W wrote: > > > > Hi, > > > > Best Regards, > > > > Xiao > > > > > -----Original Message----- > > > > > From: Jason Wang <jasow...@redhat.com> > > > > > Sent: Friday, May 15, 2020 5:09 PM > > > > > To: Maxime Coquelin <maxime.coque...@redhat.com>; Ye, Xiaolong > > > > > <xiaolong...@intel.com>; shah...@mellanox.com; ma...@mellanox.com; > > > > > amore...@redhat.com; Wang, Xiao W <xiao.w.w...@intel.com>; > > > > > viachesl...@mellanox.com; dev@dpdk.org > > > > > Cc: l...@redhat.com > > > > > Subject: Re: [PATCH 3/9] vdpa/ifc: add support to vDPA queue enable > > > > > > > > > > > > > > > On 2020/5/14 下午4:02, Maxime Coquelin wrote: > > > > > > This patch adds support to enabling and disabling > > > > > > vrings on a per-vring granularity. > > > > > > > > > > > > Signed-off-by: Maxime Coquelin <maxime.coque...@redhat.com > > <mailto:maxime.coque...@redhat.com>> > > > > > > > > > > > > > > > A question here, I see in qemu peer_attach() may try to generate > > > > > VHOST_USER_SET_VRING_ENABLE, but just from the name I think it should > > > > > behave as queue_enable defined in virtio specification which is > > > > > explicitly under the control of guest? > > > > > > > > > > (Note, in Cindy's vDPA series, we must invent new vhost_ops to differ > > > > > from this one). > > > > From my view, common_cfg.enable reg is used for registering a queue to > > hypervisor&vhost, but not ENABLE. > > > > Well, what's your definition of "enable" in this context? "Enable a queue" means traffic can pass through this queue. > > Spec said: > > queue_enable > The driver uses this to selectively prevent the device from > executing requests from this virtqueue. 1 - enabled; 0 - disabled. > > This means, if queue_enable is not set to 1, device can not execute > request for this specific virtqueue. > For queue enabling in virtio MQ case, there're 2 steps needed: 1. select a queue and write 1 to common_cfg.enable reg 2. send control vq message VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET If no step2, by default there's only 1 queue pair enabled. > > > The control queue message VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET is for > > enable/disable queue pairs. > > > > But in qemu this is hooked to VHOST_USER_SET_VRING_ENABLE, see > peer_attach(). And this patch hook VHOST_USER_SET_VRING_ENABLE to > queue_enable. > > This means IFCVF uses queue_enable instead of control vq or other > register for setting multiqueue stuff? My understanding is that IFCVF > has dedicated register to do this. > > Note setting mq is different from queue_enable, changing the number of > queues should let the underlayer NIC to properly configure its > steering/switching/filtering logic to make sure traffic were only sent > to the queues that is set by driver. > > So hooking VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET to queue_enable looks > wrong. We are on the same page. As I said we have dedicated reg designed to enable MQ (ensure traffic only sent to queues enabled by user) in VDPA case. > > > > Think about when virtio net probes, all queues are selected and > > "enabled" by init_vqs(), > > > > I think we're talking about aligning the implementation with spec not > just make it work for some specific drivers. Driver may choose to not > enable a virtqueue by not setting 1 to queue_enable. > > Thanks > > > > but MQ is not enabled until virtnet_set_channels() by user config with > > "ethtool". > > > > Based on this, below reg writing is not OK to enable MQ. IFC HW > > supports below registers for VF pass-thru case. > > > > Actually, we have specific reg designed to enable MQ in VDPA case. > > > > > > +IFCVF_WRITE_REG16(qid, &cfg->queue_select); > > > > > > +IFCVF_WRITE_REG16(enable, &cfg->queue_enable); > > > > BRs, > > > > Xiao > > > > > > > > > > Thanks > > > > > > > > > > > > > > > > --- > > > > > >drivers/vdpa/ifc/base/ifcvf.c |9 +++++++++ > > > > > >drivers/vdpa/ifc/base/ifcvf.h |4 ++++ > > > > > >drivers/vdpa/ifc/ifcvf_vdpa.c | 23 ++++++++++++++++++++++- > > > > > >3 files changed, 35 insertions(+), 1 deletion(-) > > > > > > > > > > > > diff --git a/drivers/vdpa/ifc/base/ifcvf.c > > b/drivers/vdpa/ifc/base/ifcvf.c > > > > > > index 3c0b2dff66..dd4e7468ae 100644 > > > > > > --- a/drivers/vdpa/ifc/base/ifcvf.c > > > > > > +++ b/drivers/vdpa/ifc/base/ifcvf.c > > > > > > @@ -327,3 +327,12 @@ ifcvf_get_queue_notify_off(struct ifcvf_hw > > *hw, int > > > > > qid) > > > > > >return (u8 *)hw->notify_addr[qid] - > > > > > >(u8 *)hw->mem_resource[hw->notify_region].addr; > > > > > >} > > > > > > + > > > > > > +void > > > > > > +ifcvf_queue_enable(struct ifcvf_hw *hw, u16 qid,u16 enable) > > > > > > +{ > > > > > > +struct ifcvf_pci_common_cfg *cfg = hw->common_cfg; > > > > > > + > > > > > > +IFCVF_WRITE_REG16(qid, &cfg->queue_select); > > > > > > +IFCVF_WRITE_REG16(enable, &cfg->queue_enable); > > > > > > +} > > > > > > diff --git a/drivers/vdpa/ifc/base/ifcvf.h > > b/drivers/vdpa/ifc/base/ifcvf.h
