Re: registering ioeventfd in qemu/kvm

[Paolo Bonzini <pbonzini@redhat.com>]

Il 23/08/2012 05:35, Shesha Sreenivasamurthy ha scritto:
> Hi,
> I am trying to generate eventfd upon a IO write from the guest, say it
> is at offset IO_NOTIFY_REG (0x10). When the guest writes to this
> register, I get control to QEMU's to the write function associated in
> mypci_iomem_ops. However, instead of this I would like to register an
> eventfd.
> 
> To achieve that, first I tried:
>        memory_region_add_eventfd(&mypci->bar_iomem, IO_NOTIFY_REG, 4,
> true, 1, fd);

This is the right way.  You can look (in the git tree of QEMU) at
hw/ivshmem.c, which is the simplest user of the eventfd API.

Note that recently the API was changed to accept an EventNotifier rather
than the raw eventfd.

Paolo