From: Akihiko Odaki <akihiko.odaki@daynix.com>
To: Jason Wang <jasowang@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>,
Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
Xuan Zhuo <xuanzhuo@linux.alibaba.com>,
Shuah Khan <shuah@kernel.org>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
netdev@vger.kernel.org, kvm@vger.kernel.org,
virtualization@lists.linux-foundation.org,
linux-kselftest@vger.kernel.org,
Yuri Benditovich <yuri.benditovich@daynix.com>,
Andrew Melnychenko <andrew@daynix.com>,
Stephen Hemminger <stephen@networkplumber.org>,
gur.stavi@huawei.com, devel@daynix.com
Subject: Re: [PATCH v2 3/3] tun: Set num_buffers for virtio 1.0
Date: Fri, 10 Jan 2025 19:04:07 +0900 [thread overview]
Message-ID: <1f2908ed-e938-4365-8f1e-9f1c7753fb9b@daynix.com> (raw)
In-Reply-To: <CACGkMEsm5DCb+n3NYeRjmq3rAANztZz5QmV8rbPNo+cH-=VzDQ@mail.gmail.com>
On 2025/01/10 12:27, Jason Wang wrote:
> On Thu, Jan 9, 2025 at 2:59 PM Akihiko Odaki <akihiko.odaki@daynix.com> wrote:
>>
>> The specification says the device MUST set num_buffers to 1 if
>> VIRTIO_NET_F_MRG_RXBUF has not been negotiated.
>
> Have we agreed on how to fix the spec or not?
>
> As I replied in the spec patch, if we just remove this "MUST", it
> looks like we are all fine?
My understanding is that we should fix the kernel and QEMU instead.
There may be some driver implementations that assumes num_buffers is 1
so the kernel and QEMU should be fixed to be compatible with such
potential implementations.
It is also possible to make future drivers with existing kernels and
QEMU by ensuring they will not read num_buffers when
VIRTIO_NET_F_MRG_RXBUF has not negotiated, and that's what "[PATCH v3]
virtio-net: Ignore num_buffers when unused" does.
https://lore.kernel.org/r/20250110-reserved-v3-1-2ade0a5d2090@daynix.com
Regards,
Akihiko Odaki
next prev parent reply other threads:[~2025-01-10 10:04 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-09 6:58 [PATCH v2 0/3] tun: Unify vnet implementation and fill full vnet header Akihiko Odaki
2025-01-09 6:58 ` [PATCH v2 1/3] tun: Unify vnet implementation Akihiko Odaki
2025-01-09 14:06 ` Willem de Bruijn
2025-01-10 8:28 ` Akihiko Odaki
2025-01-10 3:24 ` Jason Wang
2025-01-09 6:58 ` [PATCH v2 2/3] tun: Pad virtio header with zero Akihiko Odaki
2025-01-09 7:31 ` Michael S. Tsirkin
2025-01-09 7:41 ` Akihiko Odaki
2025-01-09 7:43 ` Michael S. Tsirkin
2025-01-09 9:36 ` Akihiko Odaki
2025-01-09 10:37 ` Jan Kara
2025-01-09 12:46 ` Willem de Bruijn
2025-01-10 4:38 ` Akihiko Odaki
2025-01-10 8:33 ` Michael S. Tsirkin
2025-01-10 10:45 ` Akihiko Odaki
2025-01-10 11:32 ` Willem de Bruijn
2025-01-09 7:42 ` Michael S. Tsirkin
2025-01-10 3:27 ` Jason Wang
2025-01-10 10:25 ` Akihiko Odaki
2025-01-09 6:58 ` [PATCH v2 3/3] tun: Set num_buffers for virtio 1.0 Akihiko Odaki
2025-01-09 7:32 ` Michael S. Tsirkin
2025-01-09 7:40 ` Michael S. Tsirkin
2025-01-09 9:38 ` Akihiko Odaki
2025-01-09 10:54 ` Michael S. Tsirkin
2025-01-09 11:10 ` Akihiko Odaki
2025-01-10 3:27 ` Jason Wang
2025-01-10 10:04 ` Akihiko Odaki [this message]
2025-01-10 10:23 ` Michael S. Tsirkin
2025-01-10 11:12 ` Akihiko Odaki
2025-01-13 3:04 ` Jason Wang
2025-01-15 5:07 ` Akihiko Odaki
2025-01-16 1:06 ` Jason Wang
2025-01-16 5:30 ` Akihiko Odaki
2025-01-20 0:40 ` Jason Wang
2025-01-20 4:57 ` Akihiko Odaki
2025-01-09 13:46 ` [PATCH v2 0/3] tun: Unify vnet implementation and fill full vnet header Willem de Bruijn
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