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From:   Alvaro Karsz <alvaro.karsz@solid-run.com>
To:     "Michael S. Tsirkin" <mst@redhat.com>
CC:     Jason Wang <jasowang@redhat.com>,
        "davem@davemloft.net" <davem@davemloft.net>,
        "edumazet@google.com" <edumazet@google.com>,
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        "virtualization@lists.linux-foundation.org" 
        <virtualization@lists.linux-foundation.org>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH net] virtio-net: reject small vring sizes
Thread-Topic: [PATCH net] virtio-net: reject small vring sizes
Thread-Index: AQHZcDeGnH5xR2OGlkuo4s6jvhNMC68uIjT9gABGFgCAAG90AIAAMSwAgAABjzCAAARBAIAABATIgAAENICAAAM4M4AAIQOAgAALfyGAABuqgIAAAQKHgAADxACACRVQMQ==
Date:   Sun, 23 Apr 2023 06:51:46 +0000
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> Yes that makes sense, it's architetural. We can disable ctrl vq though.=
=0A=
=0A=
The problem here is that we know the vring size after calling virtnet_find_=
vqs, so the number of VQs already includes the control VQ.=0A=
=0A=
Actually, many variables/settings that are initialized before we call virtn=
et_find_vqs may need modifications if we use small vrings.=0A=
For example has_rss_hash_report, has_rss, hdr_len etc..=0A=
=0A=
We could have a fixup function to fix everything after we discover that we =
are using small vrings, but, honestly, I think that this will be hard to ma=
intain in the future, and I don't like this approach much.=0A=
=0A=
The ideal thing will be to discover if we use small vrings in probe's begin=
ning.=0A=
=0A=
I'm looking for a way at the moment.=