[virtio-dev] Re: [PATCH v2] virtio_net: support split header
On Tue, May 31, 2022 at 10:10:52AM +0800, Xuan Zhuo wrote:
> On Mon, 30 May 2022 14:27:26 -0400, "Michael S. Tsirkin"
> wrote:
> > On Sat, May 07, 2022 at 03:15:33PM +0800, Xuan Zhuo wrote:
> > > The purpose of this feature is to split the header and the payload of
> > > the packet.
> > >
> > > |receive buffer|
> > > | 0th descriptor | 1th descriptor|
> > > | virtnet hdr | mac | ip hdr | tcp hdr|<-- hold -->| payload |
> > >
> > > We can use a buffer plus a separate page when allocating the receive
> > > buffer. In this way, we can ensure that all payloads can be
> > > independently in a page, which is very beneficial for the zerocopy
> > > implemented by the upper layer.
> > >
> > > Signed-off-by: Xuan Zhuo
> >
> > Okay, but I don't think this covers all possible use-cases.
> > If we are doing this let's try to address alignment requirements too.
>
> Very happy to do this job.
>
> I thinks "offset" can contain these requirements.
I am not so sure. The issue is with all of the extension headers where
the payload is is not always predictable, even for a
given type.
> No matter how many descriptors
> are used, we treat multiple buffers as a continuous piece of memory. The
> device
> places ip, tcp/udp at the specified location according to the specified
> offset.
>
> The device does not care whether the data is finally aligned with the buffer
> specified by a descriptor, the device only needs to ensure that each layer of
> the protocol is placed on the specified "offset".
>
> Many other places need to be modified, and I will publish a new spec.
>
> Thanks.
>
> >
> > > ---
> > > conformance.tex | 2 ++
> > > content.tex | 72 +
> > > 2 files changed, 74 insertions(+)
> > >
> > > diff --git a/conformance.tex b/conformance.tex
> > > index 663e7c3..6f561fb 100644
> > > --- a/conformance.tex
> > > +++ b/conformance.tex
> > > @@ -149,6 +149,7 @@ \section{Conformance Targets}\label{sec:Conformance /
> > > Conformance Targets}
> > > \item \ref{drivernormative:Device Types / Network Device / Device
> > > Operation / Control Virtqueue / Automatic receive steering in multiqueue
> > > mode}
> > > \item \ref{drivernormative:Device Types / Network Device / Device
> > > Operation / Control Virtqueue / Offloads State Configuration / Setting
> > > Offloads State}
> > > \item \ref{drivernormative:Device Types / Network Device / Device
> > > Operation / Control Virtqueue / Receive-side scaling (RSS) }
> > > +\item \ref{drivernormative:Device Types / Network Device / Device
> > > Operation / Control Virtqueue / Split Header}
> > > \end{itemize}
> > >
> > > \conformance{\subsection}{Block Driver
> > > Conformance}\label{sec:Conformance / Driver Conformance / Block Driver
> > > Conformance}
> > > @@ -411,6 +412,7 @@ \section{Conformance Targets}\label{sec:Conformance /
> > > Conformance Targets}
> > > \item \ref{devicenormative:Device Types / Network Device / Device
> > > Operation / Control Virtqueue / Gratuitous Packet Sending}
> > > \item \ref{devicenormative:Device Types / Network Device / Device
> > > Operation / Control Virtqueue / Automatic receive steering in multiqueue
> > > mode}
> > > \item \ref{devicenormative:Device Types / Network Device / Device
> > > Operation / Control Virtqueue / Receive-side scaling (RSS) / RSS
> > > processing}
> > > +\item \ref{devicenormative:Device Types / Network Device / Device
> > > Operation / Control Virtqueue / Split Header}
> > > \end{itemize}
> > >
> > > \conformance{\subsection}{Block Device
> > > Conformance}\label{sec:Conformance / Device Conformance / Block Device
> > > Conformance}
> > > diff --git a/content.tex b/content.tex
> > > index 060bdab..3340402 100644
> > > --- a/content.tex
> > > +++ b/content.tex
> > > @@ -3092,6 +3092,9 @@ \subsection{Feature bits}\label{sec:Device Types /
> > > Network Device / Feature bits
> > > \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through control
> > > channel.
> > >
> > > +\item[VIRTIO_NET_F_SPLIT_HEADER (55)] Device supports to split the
> > > header and
> > > +the payload.
> > > +
> > > \item[VIRTIO_NET_F_HOST_USO (56)] Device can receive USO packets. Unlike
> > > UFO
> > > (fragmenting the packet) the USO splits large UDP packet
> > > to several segments when each of these smaller packets has UDP header.
> > > @@ -3139,6 +3142,7 @@ \subsubsection{Feature bit
> > > requirements}\label{sec:Device Types / Network Device
> > > \item[VIRTIO_NET_F_CTRL_MAC_ADDR] Requires VIRTIO_NET_F_CTRL_VQ.
> > > \item[VIRTIO_NET_F_RSC_EXT] Requires VIRTIO_NET_F_HOST_TSO4 or
> > > VIRTIO_NET_F_HOST_TSO6.
> > > \item[VIRTIO_NET_F_RSS] Requires VIRTIO_NET_F_CTRL_VQ.
> > > +\item[VIRTIO_NET_F_SPLIT_HEADER] Requires VIRTIO_NET_F_CTRL_VQ.
> > > \end{description}
> > >
> > > \subsubsection{Legacy Interface: Feature
Re: [virtio-dev] Re: [PATCH v2] virtio_net: support split header
On Tue, May 31, 2022 at 12:38:14PM +0800, Jason Wang wrote:
> On Tue, May 31, 2022 at 2:23 AM Michael S. Tsirkin wrote:
> >
> > On Mon, May 30, 2022 at 01:56:06PM +0800, Jason Wang wrote:
> > > On Thu, May 26, 2022 at 2:31 PM Xuan Zhuo
> > > wrote:
> > > >
> > > > On Mon, 9 May 2022 16:41:11 +0800, Jason Wang
> > > > wrote:
> > > > >
> > > > > 在 2022/5/7 15:15, Xuan Zhuo 写道:
> > > > > > The purpose of this feature is to split the header and the payload
> > > > > > of
> > > > > > the packet.
> > > > > >
> > > > > > |receive buffer
> > > > > >|
> > > > > > | 0th descriptor | 1th descriptor
> > > > > >|
> > > > > > | virtnet hdr | mac | ip hdr | tcp hdr|<-- hold -->| payload
> > > > > >|
> > > > > >
> > > > > > We can use a buffer plus a separate page when allocating the receive
> > > > > > buffer. In this way, we can ensure that all payloads can be
> > > > > > independently in a page, which is very beneficial for the zerocopy
> > > > > > implemented by the upper layer.
> > > > > >
> > > > > > Signed-off-by: Xuan Zhuo
> > > > > > ---
> > > > > > conformance.tex | 2 ++
> > > > > > content.tex | 72
> > > > > > +
> > > > > > 2 files changed, 74 insertions(+)
> > > > > >
> > > > > > diff --git a/conformance.tex b/conformance.tex
> > > > > > index 663e7c3..6f561fb 100644
> > > > > > --- a/conformance.tex
> > > > > > +++ b/conformance.tex
> > > > > > @@ -149,6 +149,7 @@ \section{Conformance
> > > > > > Targets}\label{sec:Conformance / Conformance Targets}
> > > > > > \item \ref{drivernormative:Device Types / Network Device / Device
> > > > > > Operation / Control Virtqueue / Automatic receive steering in
> > > > > > multiqueue mode}
> > > > > > \item \ref{drivernormative:Device Types / Network Device / Device
> > > > > > Operation / Control Virtqueue / Offloads State Configuration /
> > > > > > Setting Offloads State}
> > > > > > \item \ref{drivernormative:Device Types / Network Device / Device
> > > > > > Operation / Control Virtqueue / Receive-side scaling (RSS) }
> > > > > > +\item \ref{drivernormative:Device Types / Network Device / Device
> > > > > > Operation / Control Virtqueue / Split Header}
> > > > > > \end{itemize}
> > > > > >
> > > > > > \conformance{\subsection}{Block Driver
> > > > > > Conformance}\label{sec:Conformance / Driver Conformance / Block
> > > > > > Driver Conformance}
> > > > > > @@ -411,6 +412,7 @@ \section{Conformance
> > > > > > Targets}\label{sec:Conformance / Conformance Targets}
> > > > > > \item \ref{devicenormative:Device Types / Network Device / Device
> > > > > > Operation / Control Virtqueue / Gratuitous Packet Sending}
> > > > > > \item \ref{devicenormative:Device Types / Network Device / Device
> > > > > > Operation / Control Virtqueue / Automatic receive steering in
> > > > > > multiqueue mode}
> > > > > > \item \ref{devicenormative:Device Types / Network Device / Device
> > > > > > Operation / Control Virtqueue / Receive-side scaling (RSS) / RSS
> > > > > > processing}
> > > > > > +\item \ref{devicenormative:Device Types / Network Device / Device
> > > > > > Operation / Control Virtqueue / Split Header}
> > > > > > \end{itemize}
> > > > > >
> > > > > > \conformance{\subsection}{Block Device
> > > > > > Conformance}\label{sec:Conformance / Device Conformance / Block
> > > > > > Device Conformance}
> > > > > > diff --git a/content.tex b/content.tex
> > > > > > index 060bdab..3340402 100644
> > > > > > --- a/content.tex
> > > > > > +++ b/content.tex
> > > > > > @@ -3092,6 +3092,9 @@ \subsection{Feature bits}\label{sec:Device
> > > > > > Types / Network Device / Feature bits
> > > > > > \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through
> > > > > > control
> > > > > > channel.
> > > > > >
> > > > > > +\item[VIRTIO_NET_F_SPLIT_HEADER (55)] Device supports to split the
> > > > > > header and
> > > > > > +the payload.
> > > > > > +
> > > > > > \item[VIRTIO_NET_F_HOST_USO (56)] Device can receive USO packets.
> > > > > > Unlike UFO
> > > > > >(fragmenting the packet) the USO splits large UDP packet
> > > > > >to several segments when each of these smaller packets has UDP
> > > > > > header.
> > > > > > @@ -3139,6 +3142,7 @@ \subsubsection{Feature bit
> > > > > > requirements}\label{sec:Device Types / Network Device
> > > > > > \item[VIRTIO_NET_F_CTRL_MAC_ADDR] Requires VIRTIO_NET_F_CTRL_VQ.
> > > > > > \item[VIRTIO_NET_F_RSC_EXT] Requires VIRTIO_NET_F_HOST_TSO4 or
> > > > > > VIRTIO_NET_F_HOST_TSO6.
> > > > > > \item[VIRTIO_NET_F_RSS] Requires VIRTIO_NET_F_CTRL_VQ.
> > > > > > +\item[VIRTIO_NET_F_SPLIT_HEADER] Requires VIRTIO_NET_F_CTRL_VQ.
> > > > > > \end{description}
> > > > > >
> > > > > > \subsubsection{Legacy Interface: Feature bits}\label{sec:Device
> > > > > > Types / Network Device / Feature bits / Legacy
[virtio-dev] Re: [PATCH v2] virtio_net: support split header
On Tue, May 31, 2022 at 10:10:52AM +0800, Xuan Zhuo wrote:
> On Mon, 30 May 2022 14:27:26 -0400, "Michael S. Tsirkin"
> wrote:
> > On Sat, May 07, 2022 at 03:15:33PM +0800, Xuan Zhuo wrote:
> > > The purpose of this feature is to split the header and the payload of
> > > the packet.
> > >
> > > |receive buffer|
> > > | 0th descriptor | 1th descriptor|
> > > | virtnet hdr | mac | ip hdr | tcp hdr|<-- hold -->| payload |
> > >
> > > We can use a buffer plus a separate page when allocating the receive
> > > buffer. In this way, we can ensure that all payloads can be
> > > independently in a page, which is very beneficial for the zerocopy
> > > implemented by the upper layer.
> > >
> > > Signed-off-by: Xuan Zhuo
> >
> > Okay, but I don't think this covers all possible use-cases.
> > If we are doing this let's try to address alignment requirements too.
>
> Very happy to do this job.
>
> I thinks "offset" can contain these requirements. No matter how many
> descriptors
> are used, we treat multiple buffers as a continuous piece of memory. The
> device
> places ip, tcp/udp at the specified location according to the specified
> offset.
>
> The device does not care whether the data is finally aligned with the buffer
> specified by a descriptor, the device only needs to ensure that each layer of
> the protocol is placed on the specified "offset".
>
> Many other places need to be modified, and I will publish a new spec.
>
> Thanks.
>
> >
> > > ---
> > > conformance.tex | 2 ++
> > > content.tex | 72 +
> > > 2 files changed, 74 insertions(+)
> > >
> > > diff --git a/conformance.tex b/conformance.tex
> > > index 663e7c3..6f561fb 100644
> > > --- a/conformance.tex
> > > +++ b/conformance.tex
> > > @@ -149,6 +149,7 @@ \section{Conformance Targets}\label{sec:Conformance /
> > > Conformance Targets}
> > > \item \ref{drivernormative:Device Types / Network Device / Device
> > > Operation / Control Virtqueue / Automatic receive steering in multiqueue
> > > mode}
> > > \item \ref{drivernormative:Device Types / Network Device / Device
> > > Operation / Control Virtqueue / Offloads State Configuration / Setting
> > > Offloads State}
> > > \item \ref{drivernormative:Device Types / Network Device / Device
> > > Operation / Control Virtqueue / Receive-side scaling (RSS) }
> > > +\item \ref{drivernormative:Device Types / Network Device / Device
> > > Operation / Control Virtqueue / Split Header}
> > > \end{itemize}
> > >
> > > \conformance{\subsection}{Block Driver
> > > Conformance}\label{sec:Conformance / Driver Conformance / Block Driver
> > > Conformance}
> > > @@ -411,6 +412,7 @@ \section{Conformance Targets}\label{sec:Conformance /
> > > Conformance Targets}
> > > \item \ref{devicenormative:Device Types / Network Device / Device
> > > Operation / Control Virtqueue / Gratuitous Packet Sending}
> > > \item \ref{devicenormative:Device Types / Network Device / Device
> > > Operation / Control Virtqueue / Automatic receive steering in multiqueue
> > > mode}
> > > \item \ref{devicenormative:Device Types / Network Device / Device
> > > Operation / Control Virtqueue / Receive-side scaling (RSS) / RSS
> > > processing}
> > > +\item \ref{devicenormative:Device Types / Network Device / Device
> > > Operation / Control Virtqueue / Split Header}
> > > \end{itemize}
> > >
> > > \conformance{\subsection}{Block Device
> > > Conformance}\label{sec:Conformance / Device Conformance / Block Device
> > > Conformance}
> > > diff --git a/content.tex b/content.tex
> > > index 060bdab..3340402 100644
> > > --- a/content.tex
> > > +++ b/content.tex
> > > @@ -3092,6 +3092,9 @@ \subsection{Feature bits}\label{sec:Device Types /
> > > Network Device / Feature bits
> > > \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through control
> > > channel.
> > >
> > > +\item[VIRTIO_NET_F_SPLIT_HEADER (55)] Device supports to split the
> > > header and
> > > +the payload.
> > > +
> > > \item[VIRTIO_NET_F_HOST_USO (56)] Device can receive USO packets. Unlike
> > > UFO
> > > (fragmenting the packet) the USO splits large UDP packet
> > > to several segments when each of these smaller packets has UDP header.
> > > @@ -3139,6 +3142,7 @@ \subsubsection{Feature bit
> > > requirements}\label{sec:Device Types / Network Device
> > > \item[VIRTIO_NET_F_CTRL_MAC_ADDR] Requires VIRTIO_NET_F_CTRL_VQ.
> > > \item[VIRTIO_NET_F_RSC_EXT] Requires VIRTIO_NET_F_HOST_TSO4 or
> > > VIRTIO_NET_F_HOST_TSO6.
> > > \item[VIRTIO_NET_F_RSS] Requires VIRTIO_NET_F_CTRL_VQ.
> > > +\item[VIRTIO_NET_F_SPLIT_HEADER] Requires VIRTIO_NET_F_CTRL_VQ.
> > > \end{description}
> > >
> > > \subsubsection{Legacy Interface: Feature bits}\label{sec:Device Types /
> > > Network Device / Feature bits / Legacy Interface: Feature bits}
> > > @@ -3370,6 +3374,7 @@ \subsection{Device
Re: [virtio-dev] Re: [PATCH v2] virtio_net: support split header
On Tue, May 31, 2022 at 2:23 AM Michael S. Tsirkin wrote:
>
> On Mon, May 30, 2022 at 01:56:06PM +0800, Jason Wang wrote:
> > On Thu, May 26, 2022 at 2:31 PM Xuan Zhuo
> > wrote:
> > >
> > > On Mon, 9 May 2022 16:41:11 +0800, Jason Wang wrote:
> > > >
> > > > 在 2022/5/7 15:15, Xuan Zhuo 写道:
> > > > > The purpose of this feature is to split the header and the payload of
> > > > > the packet.
> > > > >
> > > > > |receive buffer
> > > > > |
> > > > > | 0th descriptor | 1th descriptor
> > > > > |
> > > > > | virtnet hdr | mac | ip hdr | tcp hdr|<-- hold -->| payload
> > > > > |
> > > > >
> > > > > We can use a buffer plus a separate page when allocating the receive
> > > > > buffer. In this way, we can ensure that all payloads can be
> > > > > independently in a page, which is very beneficial for the zerocopy
> > > > > implemented by the upper layer.
> > > > >
> > > > > Signed-off-by: Xuan Zhuo
> > > > > ---
> > > > > conformance.tex | 2 ++
> > > > > content.tex | 72
> > > > > +
> > > > > 2 files changed, 74 insertions(+)
> > > > >
> > > > > diff --git a/conformance.tex b/conformance.tex
> > > > > index 663e7c3..6f561fb 100644
> > > > > --- a/conformance.tex
> > > > > +++ b/conformance.tex
> > > > > @@ -149,6 +149,7 @@ \section{Conformance
> > > > > Targets}\label{sec:Conformance / Conformance Targets}
> > > > > \item \ref{drivernormative:Device Types / Network Device / Device
> > > > > Operation / Control Virtqueue / Automatic receive steering in
> > > > > multiqueue mode}
> > > > > \item \ref{drivernormative:Device Types / Network Device / Device
> > > > > Operation / Control Virtqueue / Offloads State Configuration /
> > > > > Setting Offloads State}
> > > > > \item \ref{drivernormative:Device Types / Network Device / Device
> > > > > Operation / Control Virtqueue / Receive-side scaling (RSS) }
> > > > > +\item \ref{drivernormative:Device Types / Network Device / Device
> > > > > Operation / Control Virtqueue / Split Header}
> > > > > \end{itemize}
> > > > >
> > > > > \conformance{\subsection}{Block Driver
> > > > > Conformance}\label{sec:Conformance / Driver Conformance / Block
> > > > > Driver Conformance}
> > > > > @@ -411,6 +412,7 @@ \section{Conformance
> > > > > Targets}\label{sec:Conformance / Conformance Targets}
> > > > > \item \ref{devicenormative:Device Types / Network Device / Device
> > > > > Operation / Control Virtqueue / Gratuitous Packet Sending}
> > > > > \item \ref{devicenormative:Device Types / Network Device / Device
> > > > > Operation / Control Virtqueue / Automatic receive steering in
> > > > > multiqueue mode}
> > > > > \item \ref{devicenormative:Device Types / Network Device / Device
> > > > > Operation / Control Virtqueue / Receive-side scaling (RSS) / RSS
> > > > > processing}
> > > > > +\item \ref{devicenormative:Device Types / Network Device / Device
> > > > > Operation / Control Virtqueue / Split Header}
> > > > > \end{itemize}
> > > > >
> > > > > \conformance{\subsection}{Block Device
> > > > > Conformance}\label{sec:Conformance / Device Conformance / Block
> > > > > Device Conformance}
> > > > > diff --git a/content.tex b/content.tex
> > > > > index 060bdab..3340402 100644
> > > > > --- a/content.tex
> > > > > +++ b/content.tex
> > > > > @@ -3092,6 +3092,9 @@ \subsection{Feature bits}\label{sec:Device
> > > > > Types / Network Device / Feature bits
> > > > > \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through
> > > > > control
> > > > > channel.
> > > > >
> > > > > +\item[VIRTIO_NET_F_SPLIT_HEADER (55)] Device supports to split the
> > > > > header and
> > > > > +the payload.
> > > > > +
> > > > > \item[VIRTIO_NET_F_HOST_USO (56)] Device can receive USO packets.
> > > > > Unlike UFO
> > > > >(fragmenting the packet) the USO splits large UDP packet
> > > > >to several segments when each of these smaller packets has UDP
> > > > > header.
> > > > > @@ -3139,6 +3142,7 @@ \subsubsection{Feature bit
> > > > > requirements}\label{sec:Device Types / Network Device
> > > > > \item[VIRTIO_NET_F_CTRL_MAC_ADDR] Requires VIRTIO_NET_F_CTRL_VQ.
> > > > > \item[VIRTIO_NET_F_RSC_EXT] Requires VIRTIO_NET_F_HOST_TSO4 or
> > > > > VIRTIO_NET_F_HOST_TSO6.
> > > > > \item[VIRTIO_NET_F_RSS] Requires VIRTIO_NET_F_CTRL_VQ.
> > > > > +\item[VIRTIO_NET_F_SPLIT_HEADER] Requires VIRTIO_NET_F_CTRL_VQ.
> > > > > \end{description}
> > > > >
> > > > > \subsubsection{Legacy Interface: Feature bits}\label{sec:Device
> > > > > Types / Network Device / Feature bits / Legacy Interface: Feature
> > > > > bits}
> > > > > @@ -3370,6 +3374,7 @@ \subsection{Device Operation}\label{sec:Device
> > > > > Types / Network Device / Device O
> > > > > #define VIRTIO_NET_HDR_F_NEEDS_CSUM1
> > > > > #define VIRTIO_NET_HDR_F_DATA_VALID2
> > > > > #define
[virtio-dev] Re: [PATCH v2] virtio_net: support split header
On Mon, 30 May 2022 14:27:26 -0400, "Michael S. Tsirkin"
wrote:
> On Sat, May 07, 2022 at 03:15:33PM +0800, Xuan Zhuo wrote:
> > The purpose of this feature is to split the header and the payload of
> > the packet.
> >
> > |receive buffer|
> > | 0th descriptor | 1th descriptor|
> > | virtnet hdr | mac | ip hdr | tcp hdr|<-- hold -->| payload |
> >
> > We can use a buffer plus a separate page when allocating the receive
> > buffer. In this way, we can ensure that all payloads can be
> > independently in a page, which is very beneficial for the zerocopy
> > implemented by the upper layer.
> >
> > Signed-off-by: Xuan Zhuo
>
> Okay, but I don't think this covers all possible use-cases.
> If we are doing this let's try to address alignment requirements too.
Very happy to do this job.
I thinks "offset" can contain these requirements. No matter how many descriptors
are used, we treat multiple buffers as a continuous piece of memory. The device
places ip, tcp/udp at the specified location according to the specified offset.
The device does not care whether the data is finally aligned with the buffer
specified by a descriptor, the device only needs to ensure that each layer of
the protocol is placed on the specified "offset".
Many other places need to be modified, and I will publish a new spec.
Thanks.
>
> > ---
> > conformance.tex | 2 ++
> > content.tex | 72 +
> > 2 files changed, 74 insertions(+)
> >
> > diff --git a/conformance.tex b/conformance.tex
> > index 663e7c3..6f561fb 100644
> > --- a/conformance.tex
> > +++ b/conformance.tex
> > @@ -149,6 +149,7 @@ \section{Conformance Targets}\label{sec:Conformance /
> > Conformance Targets}
> > \item \ref{drivernormative:Device Types / Network Device / Device
> > Operation / Control Virtqueue / Automatic receive steering in multiqueue
> > mode}
> > \item \ref{drivernormative:Device Types / Network Device / Device
> > Operation / Control Virtqueue / Offloads State Configuration / Setting
> > Offloads State}
> > \item \ref{drivernormative:Device Types / Network Device / Device
> > Operation / Control Virtqueue / Receive-side scaling (RSS) }
> > +\item \ref{drivernormative:Device Types / Network Device / Device
> > Operation / Control Virtqueue / Split Header}
> > \end{itemize}
> >
> > \conformance{\subsection}{Block Driver Conformance}\label{sec:Conformance
> > / Driver Conformance / Block Driver Conformance}
> > @@ -411,6 +412,7 @@ \section{Conformance Targets}\label{sec:Conformance /
> > Conformance Targets}
> > \item \ref{devicenormative:Device Types / Network Device / Device
> > Operation / Control Virtqueue / Gratuitous Packet Sending}
> > \item \ref{devicenormative:Device Types / Network Device / Device
> > Operation / Control Virtqueue / Automatic receive steering in multiqueue
> > mode}
> > \item \ref{devicenormative:Device Types / Network Device / Device
> > Operation / Control Virtqueue / Receive-side scaling (RSS) / RSS processing}
> > +\item \ref{devicenormative:Device Types / Network Device / Device
> > Operation / Control Virtqueue / Split Header}
> > \end{itemize}
> >
> > \conformance{\subsection}{Block Device Conformance}\label{sec:Conformance
> > / Device Conformance / Block Device Conformance}
> > diff --git a/content.tex b/content.tex
> > index 060bdab..3340402 100644
> > --- a/content.tex
> > +++ b/content.tex
> > @@ -3092,6 +3092,9 @@ \subsection{Feature bits}\label{sec:Device Types /
> > Network Device / Feature bits
> > \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through control
> > channel.
> >
> > +\item[VIRTIO_NET_F_SPLIT_HEADER (55)] Device supports to split the header
> > and
> > +the payload.
> > +
> > \item[VIRTIO_NET_F_HOST_USO (56)] Device can receive USO packets. Unlike
> > UFO
> > (fragmenting the packet) the USO splits large UDP packet
> > to several segments when each of these smaller packets has UDP header.
> > @@ -3139,6 +3142,7 @@ \subsubsection{Feature bit
> > requirements}\label{sec:Device Types / Network Device
> > \item[VIRTIO_NET_F_CTRL_MAC_ADDR] Requires VIRTIO_NET_F_CTRL_VQ.
> > \item[VIRTIO_NET_F_RSC_EXT] Requires VIRTIO_NET_F_HOST_TSO4 or
> > VIRTIO_NET_F_HOST_TSO6.
> > \item[VIRTIO_NET_F_RSS] Requires VIRTIO_NET_F_CTRL_VQ.
> > +\item[VIRTIO_NET_F_SPLIT_HEADER] Requires VIRTIO_NET_F_CTRL_VQ.
> > \end{description}
> >
> > \subsubsection{Legacy Interface: Feature bits}\label{sec:Device Types /
> > Network Device / Feature bits / Legacy Interface: Feature bits}
> > @@ -3370,6 +3374,7 @@ \subsection{Device Operation}\label{sec:Device Types
> > / Network Device / Device O
> > #define VIRTIO_NET_HDR_F_NEEDS_CSUM1
> > #define VIRTIO_NET_HDR_F_DATA_VALID2
> > #define VIRTIO_NET_HDR_F_RSC_INFO 4
> > +#define VIRTIO_NET_HDR_F_SPLIT_HEADER 8
> > u8 flags;
> > #define
[virtio-dev] Re: [PATCH v2] virtio_net: support split header
On Sat, May 07, 2022 at 03:15:33PM +0800, Xuan Zhuo wrote:
> The purpose of this feature is to split the header and the payload of
> the packet.
>
> |receive buffer|
> | 0th descriptor | 1th descriptor|
> | virtnet hdr | mac | ip hdr | tcp hdr|<-- hold -->| payload |
>
> We can use a buffer plus a separate page when allocating the receive
> buffer. In this way, we can ensure that all payloads can be
> independently in a page, which is very beneficial for the zerocopy
> implemented by the upper layer.
>
> Signed-off-by: Xuan Zhuo
Okay, but I don't think this covers all possible use-cases.
If we are doing this let's try to address alignment requirements too.
> ---
> conformance.tex | 2 ++
> content.tex | 72 +
> 2 files changed, 74 insertions(+)
>
> diff --git a/conformance.tex b/conformance.tex
> index 663e7c3..6f561fb 100644
> --- a/conformance.tex
> +++ b/conformance.tex
> @@ -149,6 +149,7 @@ \section{Conformance Targets}\label{sec:Conformance /
> Conformance Targets}
> \item \ref{drivernormative:Device Types / Network Device / Device Operation
> / Control Virtqueue / Automatic receive steering in multiqueue mode}
> \item \ref{drivernormative:Device Types / Network Device / Device Operation
> / Control Virtqueue / Offloads State Configuration / Setting Offloads State}
> \item \ref{drivernormative:Device Types / Network Device / Device Operation
> / Control Virtqueue / Receive-side scaling (RSS) }
> +\item \ref{drivernormative:Device Types / Network Device / Device Operation
> / Control Virtqueue / Split Header}
> \end{itemize}
>
> \conformance{\subsection}{Block Driver Conformance}\label{sec:Conformance /
> Driver Conformance / Block Driver Conformance}
> @@ -411,6 +412,7 @@ \section{Conformance Targets}\label{sec:Conformance /
> Conformance Targets}
> \item \ref{devicenormative:Device Types / Network Device / Device Operation
> / Control Virtqueue / Gratuitous Packet Sending}
> \item \ref{devicenormative:Device Types / Network Device / Device Operation
> / Control Virtqueue / Automatic receive steering in multiqueue mode}
> \item \ref{devicenormative:Device Types / Network Device / Device Operation
> / Control Virtqueue / Receive-side scaling (RSS) / RSS processing}
> +\item \ref{devicenormative:Device Types / Network Device / Device Operation
> / Control Virtqueue / Split Header}
> \end{itemize}
>
> \conformance{\subsection}{Block Device Conformance}\label{sec:Conformance /
> Device Conformance / Block Device Conformance}
> diff --git a/content.tex b/content.tex
> index 060bdab..3340402 100644
> --- a/content.tex
> +++ b/content.tex
> @@ -3092,6 +3092,9 @@ \subsection{Feature bits}\label{sec:Device Types /
> Network Device / Feature bits
> \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through control
> channel.
>
> +\item[VIRTIO_NET_F_SPLIT_HEADER (55)] Device supports to split the header and
> +the payload.
> +
> \item[VIRTIO_NET_F_HOST_USO (56)] Device can receive USO packets. Unlike UFO
> (fragmenting the packet) the USO splits large UDP packet
> to several segments when each of these smaller packets has UDP header.
> @@ -3139,6 +3142,7 @@ \subsubsection{Feature bit
> requirements}\label{sec:Device Types / Network Device
> \item[VIRTIO_NET_F_CTRL_MAC_ADDR] Requires VIRTIO_NET_F_CTRL_VQ.
> \item[VIRTIO_NET_F_RSC_EXT] Requires VIRTIO_NET_F_HOST_TSO4 or
> VIRTIO_NET_F_HOST_TSO6.
> \item[VIRTIO_NET_F_RSS] Requires VIRTIO_NET_F_CTRL_VQ.
> +\item[VIRTIO_NET_F_SPLIT_HEADER] Requires VIRTIO_NET_F_CTRL_VQ.
> \end{description}
>
> \subsubsection{Legacy Interface: Feature bits}\label{sec:Device Types /
> Network Device / Feature bits / Legacy Interface: Feature bits}
> @@ -3370,6 +3374,7 @@ \subsection{Device Operation}\label{sec:Device Types /
> Network Device / Device O
> #define VIRTIO_NET_HDR_F_NEEDS_CSUM1
> #define VIRTIO_NET_HDR_F_DATA_VALID2
> #define VIRTIO_NET_HDR_F_RSC_INFO 4
> +#define VIRTIO_NET_HDR_F_SPLIT_HEADER 8
> u8 flags;
> #define VIRTIO_NET_HDR_GSO_NONE0
> #define VIRTIO_NET_HDR_GSO_TCPV4 1
> @@ -4471,6 +4476,73 @@ \subsubsection{Control Virtqueue}\label{sec:Device
> Types / Network Device / Devi
> according to the native endian of the guest rather than
> (necessarily when not using the legacy interface) little-endian.
>
> +\paragraph{Split Header}\label{sec:Device Types / Network Device / Device
> Operation / Control Virtqueue / Split Header}
> +
> +If the VIRTIO_NET_F_SPLIT_HEADER feature is negotiated,
> +the device supports to split the header and the payload.
> +The header and payload will be separated into different buffers.
> +
> +\subparagraph{Split Header}\label{sec:Device Types / Network Device / Device
> Operation / Control Virtqueue / Split Header / Setting Split Header}
> +
> +To configure the split
Re: [virtio-dev] Re: [PATCH v2] virtio_net: support split header
On Mon, May 30, 2022 at 01:56:06PM +0800, Jason Wang wrote:
> On Thu, May 26, 2022 at 2:31 PM Xuan Zhuo wrote:
> >
> > On Mon, 9 May 2022 16:41:11 +0800, Jason Wang wrote:
> > >
> > > 在 2022/5/7 15:15, Xuan Zhuo 写道:
> > > > The purpose of this feature is to split the header and the payload of
> > > > the packet.
> > > >
> > > > |receive buffer|
> > > > | 0th descriptor | 1th descriptor|
> > > > | virtnet hdr | mac | ip hdr | tcp hdr|<-- hold -->| payload |
> > > >
> > > > We can use a buffer plus a separate page when allocating the receive
> > > > buffer. In this way, we can ensure that all payloads can be
> > > > independently in a page, which is very beneficial for the zerocopy
> > > > implemented by the upper layer.
> > > >
> > > > Signed-off-by: Xuan Zhuo
> > > > ---
> > > > conformance.tex | 2 ++
> > > > content.tex | 72 +
> > > > 2 files changed, 74 insertions(+)
> > > >
> > > > diff --git a/conformance.tex b/conformance.tex
> > > > index 663e7c3..6f561fb 100644
> > > > --- a/conformance.tex
> > > > +++ b/conformance.tex
> > > > @@ -149,6 +149,7 @@ \section{Conformance Targets}\label{sec:Conformance
> > > > / Conformance Targets}
> > > > \item \ref{drivernormative:Device Types / Network Device / Device
> > > > Operation / Control Virtqueue / Automatic receive steering in
> > > > multiqueue mode}
> > > > \item \ref{drivernormative:Device Types / Network Device / Device
> > > > Operation / Control Virtqueue / Offloads State Configuration / Setting
> > > > Offloads State}
> > > > \item \ref{drivernormative:Device Types / Network Device / Device
> > > > Operation / Control Virtqueue / Receive-side scaling (RSS) }
> > > > +\item \ref{drivernormative:Device Types / Network Device / Device
> > > > Operation / Control Virtqueue / Split Header}
> > > > \end{itemize}
> > > >
> > > > \conformance{\subsection}{Block Driver
> > > > Conformance}\label{sec:Conformance / Driver Conformance / Block Driver
> > > > Conformance}
> > > > @@ -411,6 +412,7 @@ \section{Conformance Targets}\label{sec:Conformance
> > > > / Conformance Targets}
> > > > \item \ref{devicenormative:Device Types / Network Device / Device
> > > > Operation / Control Virtqueue / Gratuitous Packet Sending}
> > > > \item \ref{devicenormative:Device Types / Network Device / Device
> > > > Operation / Control Virtqueue / Automatic receive steering in
> > > > multiqueue mode}
> > > > \item \ref{devicenormative:Device Types / Network Device / Device
> > > > Operation / Control Virtqueue / Receive-side scaling (RSS) / RSS
> > > > processing}
> > > > +\item \ref{devicenormative:Device Types / Network Device / Device
> > > > Operation / Control Virtqueue / Split Header}
> > > > \end{itemize}
> > > >
> > > > \conformance{\subsection}{Block Device
> > > > Conformance}\label{sec:Conformance / Device Conformance / Block Device
> > > > Conformance}
> > > > diff --git a/content.tex b/content.tex
> > > > index 060bdab..3340402 100644
> > > > --- a/content.tex
> > > > +++ b/content.tex
> > > > @@ -3092,6 +3092,9 @@ \subsection{Feature bits}\label{sec:Device Types
> > > > / Network Device / Feature bits
> > > > \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through control
> > > > channel.
> > > >
> > > > +\item[VIRTIO_NET_F_SPLIT_HEADER (55)] Device supports to split the
> > > > header and
> > > > +the payload.
> > > > +
> > > > \item[VIRTIO_NET_F_HOST_USO (56)] Device can receive USO packets.
> > > > Unlike UFO
> > > >(fragmenting the packet) the USO splits large UDP packet
> > > >to several segments when each of these smaller packets has UDP
> > > > header.
> > > > @@ -3139,6 +3142,7 @@ \subsubsection{Feature bit
> > > > requirements}\label{sec:Device Types / Network Device
> > > > \item[VIRTIO_NET_F_CTRL_MAC_ADDR] Requires VIRTIO_NET_F_CTRL_VQ.
> > > > \item[VIRTIO_NET_F_RSC_EXT] Requires VIRTIO_NET_F_HOST_TSO4 or
> > > > VIRTIO_NET_F_HOST_TSO6.
> > > > \item[VIRTIO_NET_F_RSS] Requires VIRTIO_NET_F_CTRL_VQ.
> > > > +\item[VIRTIO_NET_F_SPLIT_HEADER] Requires VIRTIO_NET_F_CTRL_VQ.
> > > > \end{description}
> > > >
> > > > \subsubsection{Legacy Interface: Feature bits}\label{sec:Device Types
> > > > / Network Device / Feature bits / Legacy Interface: Feature bits}
> > > > @@ -3370,6 +3374,7 @@ \subsection{Device Operation}\label{sec:Device
> > > > Types / Network Device / Device O
> > > > #define VIRTIO_NET_HDR_F_NEEDS_CSUM1
> > > > #define VIRTIO_NET_HDR_F_DATA_VALID2
> > > > #define VIRTIO_NET_HDR_F_RSC_INFO 4
> > > > +#define VIRTIO_NET_HDR_F_SPLIT_HEADER 8
> > > > u8 flags;
> > > > #define VIRTIO_NET_HDR_GSO_NONE0
> > > > #define VIRTIO_NET_HDR_GSO_TCPV4 1
> > > > @@ -4471,6 +4476,73 @@ \subsubsection{Control
> > > > Virtqueue}\label{sec:Device Types / Network Device
