From mboxrd@z Thu Jan  1 00:00:00 1970
From: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Subject: Re: [PATCH v2 2/5] net/virtio: add interrupt configure
	for vdev
Date: Wed, 29 Mar 2017 15:30:26 +0800
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To: "Tan, Jianfeng" <jianfeng.tan@intel.com>
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On Wed, Mar 29, 2017 at 03:27:28PM +0800, Tan, Jianfeng wrote:
> 
> 
> On 3/29/2017 3:09 PM, Yuanhan Liu wrote:
> >On Wed, Mar 29, 2017 at 03:03:16PM +0800, Tan, Jianfeng wrote:
> >>
> >>On 3/29/2017 2:27 PM, Yuanhan Liu wrote:
> >>>On Tue, Mar 28, 2017 at 08:21:53AM +0000, Jianfeng Tan wrote:
> >>>>For virtio PCI devices, interrupt should be configured before setting
> >>>>VIRTIO_CONFIG_STATUS_DRIVER_OK so that QEMU can properly set eventfds
> >>>>in the host.
> >>>>
> >>>>For virtio virtual devices, VIRTIO_CONFIG_STATUS_DRIVER_OK should be
> >>>>set firstly, so that intr_handle is initialized in
> >>>>virtio_user_start_device().
> >>>I'm wondering why can't you let virtio-user follow virtio-pci?
> >>It's because that virtio-user not only counts on virtio_user_start_device()
> >>to allocate intr_handle, it also needs the information in this function to
> >>initialize this struct. For virtio-pci, similar information is from
> >>rte_intr_enable/rte_intr_efd_enable.
> >>
> >>Or do you mean we can move calling virtio_user_start_device() ahead? I can
> >>hardly find other place instead of DRIVER_OK.
> >For example, virtio_user_dev_init()?
> >
> >
> But in that way, there is only one chance to negotiate features with the
> backend. What if we change the configuration through
> rte_eth_dev_configure()?

Then there will be a reset; everything should be reset properly in the
device.

	--yliu
> 
> Yes, we can just put callfd/kickfd creation and intr_handle initialization
> into virtio_user_dev_init(), and its destructor into
> virtio_user_dev_uninit(). It sounds like a feasible way to go.
> 
> Thanks,
> Jianfeng