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Date:   Sun, 28 Feb 2021 16:34:53 -0500
From:   "Michael S. Tsirkin" <mst@redhat.com>
To:     Si-Wei Liu <si-wei.liu@oracle.com>
Cc:     Jason Wang <jasowang@redhat.com>, elic@nvidia.com,
        linux-kernel@vger.kernel.org,
        virtualization@lists.linux-foundation.org, netdev@vger.kernel.org
Subject: Re: [PATCH] vdpa/mlx5: set_features should allow reset to zero
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On Wed, Feb 24, 2021 at 10:24:41AM -0800, Si-Wei Liu wrote:
> > Detecting it isn't enough though, we will need a new ioctl to notify
> > the kernel that it's a legacy guest. Ugh :(
> Well, although I think adding an ioctl is doable, may I know what the use
> case there will be for kernel to leverage such info directly? Is there a
> case QEMU can't do with dedicate ioctls later if there's indeed
> differentiation (legacy v.s. modern) needed?

BTW a good API could be

#define VHOST_SET_ENDIAN _IOW(VHOST_VIRTIO, ?, int)
#define VHOST_GET_ENDIAN _IOW(VHOST_VIRTIO, ?, int)

we did it per vring but maybe that was a mistake ...

-- 
MST