* [RFC v2] vsock: proposal to support multiple transports at runtime
@ 2019-06-06 10:09 Stefano Garzarella
2019-08-19 13:09 ` Stefan Hajnoczi
0 siblings, 1 reply; 3+ messages in thread
From: Stefano Garzarella @ 2019-06-06 10:09 UTC (permalink / raw)
To: netdev, Stefan Hajnoczi, Dexuan Cui, Jorgen Hansen
Cc: David S. Miller, Vishnu Dasa, K. Y. Srinivasan, Haiyang Zhang,
Stephen Hemminger, Sasha Levin
Hi all,
this is a v2 of a proposal addressing the comments made by Dexuan, Stefan,
and Jorgen.
v1: https://www.spinics.net/lists/netdev/msg570274.html
We can define two types of transport that we have to handle at the same time
(e.g. in a nested VM we would have both types of transport running together):
- 'host->guest' transport, it runs in the host and it is used to communicate
with the guests of a specific hypervisor (KVM, VMWare or Hyper-V). It also
runs in the guest who has nested guests, to communicate with them.
[Phase 2]
We can support multiple 'host->guest' transport running at the same time,
but on x86 only one hypervisor uses VMX at any given time.
- 'guest->host' transport, it runs in the guest and it is used to communicate
with the host.
The main goal is to find a way to decide what transport use in these cases:
1. connect() / sendto()
a. use the 'host->guest' transport, if the destination is the guest
(dest_cid > VMADDR_CID_HOST).
[Phase 2]
In order to support multiple 'host->guest' transports running at the same
time, we should assign CIDs uniquely across all transports. In this way,
a packet generated by the host side will get directed to the appropriate
transport based on the CID.
b. use the 'guest->host' transport, if the destination is the host or the
hypervisor.
(dest_cid == VMADDR_CID_HOST || dest_cid == VMADDR_CID_HYPERVISOR)
2. listen() / recvfrom()
a. use the 'host->guest' transport, if the socket is bound to
VMADDR_CID_HOST, or it is bound to VMADDR_CID_ANY and there is no
'guest->host' transport.
We could also define a new VMADDR_CID_LISTEN_FROM_GUEST in order to
address this case.
[Phase 2]
We can support network namespaces to create independent AF_VSOCK
addressing domains:
- could be used to partition VMs between hypervisors or at a finer
granularity;
- could be used to isolate host applications from guest applications
using the same ports with CID_ANY;
b. use the 'guest->host' transport, if the socket is bound to local CID
different from the VMADDR_CID_HOST (guest CID get with
IOCTL_VM_SOCKETS_GET_LOCAL_CID), or it is bound to VMADDR_CID_ANY (to be
backward compatible).
Also in this case, we could define a new VMADDR_CID_LISTEN_FROM_HOST.
c. shared port space between transports
For incoming requests or packets, we should be able to choose which
transport use, looking at the 'port' requested.
- stream sockets already support shared port space between transports
(one port can be assigned to only one transport)
[Phase 2]
- datagram sockets will support it, but for now VMCI transport is the
default transport for any host side datagram socket (KVM and Hyper-V
do not yet support datagrams sockets)
We will make the loading of af_vsock.ko independent of the transports to
allow to:
- create a AF_VSOCK socket without any loaded transports;
- listen on a socket (e.g. bound to VMADDR_CID_ANY) without any loaded
transports;
Hopefully, we could move MODULE_ALIAS_NETPROTO(PF_VSOCK) from the
vmci_transport.ko to the af_vsock.ko.
[Jorgen will check if this will impact the existing VMware products]
Notes:
- For Hyper-V sockets, the host can only be Windows. No changes should
be required on the Windows host to support the changes on this proposal.
- Communication between guests are not allowed on any transports, so we can
drop packets sent from a guest to another guest (dest_cid >
VMADDR_CID_HOST) if the 'host->guest' transport is not available.
- [Phase 2] tag used to identify things that can be done at a later stage,
but that should be taken into account during this design.
- Namespace support will be developed in [Phase 2] or in a separate project.
Comments and suggestions are welcome.
I'll be on PTO for next two weeks, so sorry in advance if I'll answer later.
If we agree on this proposal, when I get back, I'll start working on the code
to get a first PATCH RFC.
Cheers,
Stefano
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [RFC v2] vsock: proposal to support multiple transports at runtime
2019-06-06 10:09 [RFC v2] vsock: proposal to support multiple transports at runtime Stefano Garzarella
@ 2019-08-19 13:09 ` Stefan Hajnoczi
2019-08-22 8:54 ` Stefano Garzarella
0 siblings, 1 reply; 3+ messages in thread
From: Stefan Hajnoczi @ 2019-08-19 13:09 UTC (permalink / raw)
To: Stefano Garzarella
Cc: netdev, Dexuan Cui, Jorgen Hansen, David S. Miller, Vishnu Dasa,
K. Y. Srinivasan, Haiyang Zhang, Stephen Hemminger, Sasha Levin
[-- Attachment #1: Type: text/plain, Size: 4778 bytes --]
On Thu, Jun 06, 2019 at 12:09:12PM +0200, Stefano Garzarella wrote:
>
> Hi all,
> this is a v2 of a proposal addressing the comments made by Dexuan, Stefan,
> and Jorgen.
>
> v1: https://www.spinics.net/lists/netdev/msg570274.html
>
>
>
> We can define two types of transport that we have to handle at the same time
> (e.g. in a nested VM we would have both types of transport running together):
>
> - 'host->guest' transport, it runs in the host and it is used to communicate
> with the guests of a specific hypervisor (KVM, VMWare or Hyper-V). It also
> runs in the guest who has nested guests, to communicate with them.
>
> [Phase 2]
> We can support multiple 'host->guest' transport running at the same time,
> but on x86 only one hypervisor uses VMX at any given time.
>
> - 'guest->host' transport, it runs in the guest and it is used to communicate
> with the host.
>
>
> The main goal is to find a way to decide what transport use in these cases:
> 1. connect() / sendto()
>
> a. use the 'host->guest' transport, if the destination is the guest
> (dest_cid > VMADDR_CID_HOST).
>
> [Phase 2]
> In order to support multiple 'host->guest' transports running at the same
> time, we should assign CIDs uniquely across all transports. In this way,
> a packet generated by the host side will get directed to the appropriate
> transport based on the CID.
>
> b. use the 'guest->host' transport, if the destination is the host or the
> hypervisor.
> (dest_cid == VMADDR_CID_HOST || dest_cid == VMADDR_CID_HYPERVISOR)
>
>
> 2. listen() / recvfrom()
>
> a. use the 'host->guest' transport, if the socket is bound to
> VMADDR_CID_HOST, or it is bound to VMADDR_CID_ANY and there is no
> 'guest->host' transport.
> We could also define a new VMADDR_CID_LISTEN_FROM_GUEST in order to
> address this case.
>
> [Phase 2]
> We can support network namespaces to create independent AF_VSOCK
> addressing domains:
> - could be used to partition VMs between hypervisors or at a finer
> granularity;
> - could be used to isolate host applications from guest applications
> using the same ports with CID_ANY;
>
> b. use the 'guest->host' transport, if the socket is bound to local CID
> different from the VMADDR_CID_HOST (guest CID get with
> IOCTL_VM_SOCKETS_GET_LOCAL_CID), or it is bound to VMADDR_CID_ANY (to be
> backward compatible).
> Also in this case, we could define a new VMADDR_CID_LISTEN_FROM_HOST.
>
> c. shared port space between transports
> For incoming requests or packets, we should be able to choose which
> transport use, looking at the 'port' requested.
>
> - stream sockets already support shared port space between transports
> (one port can be assigned to only one transport)
>
> [Phase 2]
> - datagram sockets will support it, but for now VMCI transport is the
> default transport for any host side datagram socket (KVM and Hyper-V
> do not yet support datagrams sockets)
>
> We will make the loading of af_vsock.ko independent of the transports to
> allow to:
> - create a AF_VSOCK socket without any loaded transports;
> - listen on a socket (e.g. bound to VMADDR_CID_ANY) without any loaded
> transports;
>
> Hopefully, we could move MODULE_ALIAS_NETPROTO(PF_VSOCK) from the
> vmci_transport.ko to the af_vsock.ko.
> [Jorgen will check if this will impact the existing VMware products]
>
> Notes:
> - For Hyper-V sockets, the host can only be Windows. No changes should
> be required on the Windows host to support the changes on this proposal.
>
> - Communication between guests are not allowed on any transports, so we can
> drop packets sent from a guest to another guest (dest_cid >
> VMADDR_CID_HOST) if the 'host->guest' transport is not available.
>
> - [Phase 2] tag used to identify things that can be done at a later stage,
> but that should be taken into account during this design.
>
> - Namespace support will be developed in [Phase 2] or in a separate project.
>
>
>
> Comments and suggestions are welcome.
> I'll be on PTO for next two weeks, so sorry in advance if I'll answer later.
>
> If we agree on this proposal, when I get back, I'll start working on the code
> to get a first PATCH RFC.
Stefano,
I've reviewed your proposal and it looks good for solving nested
virtualization.
The tricky implementation details will be supporting listen sockets,
especially with VMADDR_CID_ANY so they can be accessed from both
transports.
Stefan
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [RFC v2] vsock: proposal to support multiple transports at runtime
2019-08-19 13:09 ` Stefan Hajnoczi
@ 2019-08-22 8:54 ` Stefano Garzarella
0 siblings, 0 replies; 3+ messages in thread
From: Stefano Garzarella @ 2019-08-22 8:54 UTC (permalink / raw)
To: Stefan Hajnoczi
Cc: netdev, Dexuan Cui, Jorgen Hansen, David S. Miller, Vishnu Dasa,
K. Y. Srinivasan, Haiyang Zhang, Stephen Hemminger, Sasha Levin
On Mon, Aug 19, 2019 at 02:09:11PM +0100, Stefan Hajnoczi wrote:
> On Thu, Jun 06, 2019 at 12:09:12PM +0200, Stefano Garzarella wrote:
> >
> > Hi all,
> > this is a v2 of a proposal addressing the comments made by Dexuan, Stefan,
> > and Jorgen.
> >
> > v1: https://www.spinics.net/lists/netdev/msg570274.html
> >
> >
> >
> > We can define two types of transport that we have to handle at the same time
> > (e.g. in a nested VM we would have both types of transport running together):
> >
> > - 'host->guest' transport, it runs in the host and it is used to communicate
> > with the guests of a specific hypervisor (KVM, VMWare or Hyper-V). It also
> > runs in the guest who has nested guests, to communicate with them.
> >
> > [Phase 2]
> > We can support multiple 'host->guest' transport running at the same time,
> > but on x86 only one hypervisor uses VMX at any given time.
> >
> > - 'guest->host' transport, it runs in the guest and it is used to communicate
> > with the host.
> >
> >
> > The main goal is to find a way to decide what transport use in these cases:
> > 1. connect() / sendto()
> >
> > a. use the 'host->guest' transport, if the destination is the guest
> > (dest_cid > VMADDR_CID_HOST).
> >
> > [Phase 2]
> > In order to support multiple 'host->guest' transports running at the same
> > time, we should assign CIDs uniquely across all transports. In this way,
> > a packet generated by the host side will get directed to the appropriate
> > transport based on the CID.
> >
> > b. use the 'guest->host' transport, if the destination is the host or the
> > hypervisor.
> > (dest_cid == VMADDR_CID_HOST || dest_cid == VMADDR_CID_HYPERVISOR)
> >
> >
> > 2. listen() / recvfrom()
> >
> > a. use the 'host->guest' transport, if the socket is bound to
> > VMADDR_CID_HOST, or it is bound to VMADDR_CID_ANY and there is no
> > 'guest->host' transport.
> > We could also define a new VMADDR_CID_LISTEN_FROM_GUEST in order to
> > address this case.
> >
> > [Phase 2]
> > We can support network namespaces to create independent AF_VSOCK
> > addressing domains:
> > - could be used to partition VMs between hypervisors or at a finer
> > granularity;
> > - could be used to isolate host applications from guest applications
> > using the same ports with CID_ANY;
> >
> > b. use the 'guest->host' transport, if the socket is bound to local CID
> > different from the VMADDR_CID_HOST (guest CID get with
> > IOCTL_VM_SOCKETS_GET_LOCAL_CID), or it is bound to VMADDR_CID_ANY (to be
> > backward compatible).
> > Also in this case, we could define a new VMADDR_CID_LISTEN_FROM_HOST.
> >
> > c. shared port space between transports
> > For incoming requests or packets, we should be able to choose which
> > transport use, looking at the 'port' requested.
> >
> > - stream sockets already support shared port space between transports
> > (one port can be assigned to only one transport)
> >
> > [Phase 2]
> > - datagram sockets will support it, but for now VMCI transport is the
> > default transport for any host side datagram socket (KVM and Hyper-V
> > do not yet support datagrams sockets)
> >
> > We will make the loading of af_vsock.ko independent of the transports to
> > allow to:
> > - create a AF_VSOCK socket without any loaded transports;
> > - listen on a socket (e.g. bound to VMADDR_CID_ANY) without any loaded
> > transports;
> >
> > Hopefully, we could move MODULE_ALIAS_NETPROTO(PF_VSOCK) from the
> > vmci_transport.ko to the af_vsock.ko.
> > [Jorgen will check if this will impact the existing VMware products]
> >
> > Notes:
> > - For Hyper-V sockets, the host can only be Windows. No changes should
> > be required on the Windows host to support the changes on this proposal.
> >
> > - Communication between guests are not allowed on any transports, so we can
> > drop packets sent from a guest to another guest (dest_cid >
> > VMADDR_CID_HOST) if the 'host->guest' transport is not available.
> >
> > - [Phase 2] tag used to identify things that can be done at a later stage,
> > but that should be taken into account during this design.
> >
> > - Namespace support will be developed in [Phase 2] or in a separate project.
> >
> >
> >
> > Comments and suggestions are welcome.
> > I'll be on PTO for next two weeks, so sorry in advance if I'll answer later.
> >
> > If we agree on this proposal, when I get back, I'll start working on the code
> > to get a first PATCH RFC.
>
> Stefano,
> I've reviewed your proposal and it looks good for solving nested
> virtualization.
Hi Stefan,
Thank you very much for the review!
>
> The tricky implementation details will be supporting listen sockets,
> especially with VMADDR_CID_ANY so they can be accessed from both
> transports.
Yes, it will be tricky because the current implementation has 1 to 1
mapping with the transport callbacks.
Maybe I could move some logic in the core (e.g. for listening sockets)
to have a single point of control. (e.g. using vsk->pending_links in all
transports)
I'll work on it in the next weeks, I'll keep you updated.
Thanks,
Stefano
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2019-06-06 10:09 [RFC v2] vsock: proposal to support multiple transports at runtime Stefano Garzarella
2019-08-19 13:09 ` Stefan Hajnoczi
2019-08-22 8:54 ` Stefano Garzarella
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