Re: [PATCH v2] Shared memory device with interrupt support

[Anthony Liguori <anthony@codemonkey.ws>]

Hi Cam,

Cam Macdonell wrote:
>     Support an inter-vm shared memory device that maps a shared-memory object as a PCI device in the guest.  This patch also supports interrupts between guest by communicating over a unix domain socket.  This patch applies to the qemu-kvm repository. 
>
> This device now creates a qemu character device and sends 1-bytes messages to trigger interrupts.  Writes are trigger by writing to the "Doorbell" register on the shared memory PCI device.  The lower 8-bits of the value written to this register are sent as the 1-byte message so different meanings of interrupts can be supported.
>
> Interrupts are only supported between 2 VMs currently.  One VM must act as the server by adding "server" to the command-line argument.  Shared memory devices are created with the following command-line:
>
> -ivhshmem <shm object>,<size in MB>,[unix:<path>][,server] 
>
> Interrupts can also be used between host and guest as well by implementing a listener on the host.
>
> Cam
>   

I'd strongly recommend working these patches on qemu-devel and lkml.  I 
suspect Avi may disagree with me, but in order for this to be eventually 
merged in either place, you're going to have additional requirements put 
on you.

If it goes in via qemu-kvm.git, there's a possibility that you'll be 
forced into an ABI break down the road (consider the old hypercall and 
balloon drivers).

Regards,

Anthony Liguori