Re: [PATCH net-next v4 0/5] vsock: Add flags field in the vsock address

[Stefano Garzarella]

On Mon, Dec 14, 2020 at 06:11:17PM +0200, Andra Paraschiv wrote:
> vsock enables communication between virtual machines and the host they are
> running on. Nested VMs can be setup to use vsock channels, as the multi
> transport support has been available in the mainline since the v5.5 Linux kernel
> has been released.
>
> Implicitly, if no host->guest vsock transport is loaded, all the vsock packets
> are forwarded to the host. This behavior can be used to setup communication
> channels between sibling VMs that are running on the same host. One example can
> be the vsock channels that can be established within AWS Nitro Enclaves
> (see Documentation/virt/ne_overview.rst).
>
> To be able to explicitly mark a connection as being used for a certain use case,
> add a flags field in the vsock address data structure. The value of the flags
> field is taken into consideration when the vsock transport is assigned. This way
> can distinguish between different use cases, such as nested VMs / local
> communication and sibling VMs.
>
> The flags field can be set in the user space application connect logic. On the
> listen path, the field can be set in the kernel space logic.

I reviewed and tested all the patches, great job!

Thanks,
Stefano

> Thank you.
>
> Andra
>
> ---
>
> Patch Series Changelog
>
> The patch series is built on top of v5.10.
>
> GitHub repo branch for the latest version of the patch series:
>
> * https://github.com/andraprs/linux/tree/vsock-flag-sibling-comm-v4
>
> v3 -> v4
>
> * Rebase on top of v5.10.
> * Add check for supported flag values.
> * Update the "svm_flags" field to be 1 byte instead of 2 bytes.
> * v3: https://lore.kernel.org/lkml/20201211103241.17751-1-andraprs@xxxxxxxxxx/
>
> v2 -> v3
>
> * Rebase on top of v5.10-rc7.
> * Add "svm_flags" as a new field, not reusing "svm_reserved1".
> * Update comments to mention when the "VMADDR_FLAG_TO_HOST" flag is set in the
>  connect and listen paths.
> * Update bitwise check logic to not compare result to the flag value.
> * v2: https://lore.kernel.org/lkml/20201204170235.84387-1-andraprs@xxxxxxxxxx/
>
> v1 -> v2
>
> * Update the vsock flag naming to "VMADDR_FLAG_TO_HOST".
> * Use bitwise operators to setup and check the vsock flag.
> * Set the vsock flag on the receive path in the vsock transport assignment
>  logic.
> * Merge the checks for the g2h transport assignment in one "if" block.
> * v1: https://lore.kernel.org/lkml/20201201152505.19445-1-andraprs@xxxxxxxxxx/
>
> ---
>
> Andra Paraschiv (5):
>  vm_sockets: Add flags field in the vsock address data structure
>  vm_sockets: Add VMADDR_FLAG_TO_HOST vsock flag
>  vsock_addr: Check for supported flag values
>  af_vsock: Set VMADDR_FLAG_TO_HOST flag on the receive path
>  af_vsock: Assign the vsock transport considering the vsock address
>    flags
>
> include/uapi/linux/vm_sockets.h | 26 +++++++++++++++++++++++++-
> net/vmw_vsock/af_vsock.c        | 21 +++++++++++++++++++--
> net/vmw_vsock/vsock_addr.c      |  4 +++-
> 3 files changed, 47 insertions(+), 4 deletions(-)
>
> --
> 2.20.1 (Apple Git-117)
>
>
>
>
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