[PATCH 2/5] virt: add Bao IPC shared memory driver

[Greg KH]

On Wed, Dec 24, 2025 at 01:52:14PM +0000, joaopeixoto at osyx.tech wrote:
> From: João Peixoto <joaopeixoto at osyx.tech>
> 
> Add a new driver providing an interface for communication with guests
> hosted by the Bao hypervisor using shared-memory channels. The driver
> exposes read/write regions defined in device tree and notifies the
> hypervisor via an architecture-specific hypercall (SMC/HVC on ARM and
> SBI ecall on RISC-V).
> 
> The patch introduces:
>   - drivers/bao/ with the initial Bao IPC shared-memory implementation
>   - Kconfig entry enabling BAO_SHMEM
>   - Makefile integration for building the driver
>   - A character device interface supporting mmap(), read(), and write()
>   - Platform driver support using DT properties for channel layout
> 
> Each device instance maps its assigned shared-memory region, validates
> read/write channel configuration, and exposes a /dev/baoipc<N> node
> used by user space to exchange data with Bao guests.
> 
> Signed-off-by: João Peixoto <joaopeixoto at osyx.tech>
> ---
>  drivers/virt/Kconfig                 |   2 +
>  drivers/virt/Makefile                |   1 +
>  drivers/virt/bao/Kconfig             |   3 +
>  drivers/virt/bao/Makefile            |   3 +
>  drivers/virt/bao/ipcshmem/Kconfig    |   9 +
>  drivers/virt/bao/ipcshmem/Makefile   |   3 +
>  drivers/virt/bao/ipcshmem/ipcshmem.c | 539 +++++++++++++++++++++++++++

Why two subdirs deep for a single .c file?  Why not just put this in
drivers/virt/ instead?

thanks,

greg k-h