Michael S. Tsirkin wrote:
On Thu, Jul 30, 2009 at 01:29:52PM -0500, Anthony Liguori wrote:
Cam Macdonell wrote:
This driver allows the guest VM to access shared memory between other guest
that is a POSIX shared memory object on the host. The driver can also send
interrupts by writing to the DoorBell register.
With interrupts, the ioctl must specify the ID of the VM to receive the
interrupt or '255' for broadcast to all active VMs. The 'arg' parameter is the
destination VM and 'cmd' is the interrupt code. The value written to the
register is a bit messy. 32-bits are written to the register, the upper 16 are
the destination VM, and the lower 16 are the interrupt 'code' that the
destination guest will receive. Implemented codes (see the interrupt handler)
either call up on the device's semaphore or wake up on the wait_event queue.
These codes' uses are at the discretion of the driver so they could be
customized.
For ioctls that read values from the device (such as for getting the global ID
of the guest) the arg parameter is unused.
Cam
I think you should just use Michael's uio_pci driver. I don't think we
have a need for a new kernel interface.
If that's what you want to do, an example device that generates
interrupts in response to config writes can be found here:
http://www.archivum.info/qemu-devel@xxxxxxxxxx/2009-07/01548/%5BQemu-devel%5D_%5BPATCH%5D_qemu:_test-irq_device
Thank you, I'll have a look.
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