[libvirt] [PATCH 1/4] docs: Add documents for memory device

Paolo Bonzini pbonzini at redhat.com
Mon Nov 19 08:17:43 UTC 2012

Il 19/11/2012 04:45, Osier Yang ha scritto:
> On 2012年11月17日 06:47, Paolo Bonzini wrote:
>> Il 16/11/2012 10:59, Osier Yang ha scritto:
>>> If "path" for "ivshmem" memory device is specified, it's going
>>> to be setup with interrupts enabled. Otherwise interrupts is
>>> disabled. To be more clear, let's see the QEMU command line
>>> of both cases:
>>>    * With interrupts (/tmp/nahanni is the ivshmem server socket path)
>>>      /* This starts the ivshmem server */
>>>      % ivshmem_server -m 512 -p /tmp/foo
>>>      /* qemu command line */
>>>      -chardev socket,path=/tmp/foo,id=nahanni
>>>      -device ivshmem,chardev=nahanni,size=512m,vectors=8,ioeventfd=on
>>>    * Without interrupts (no ivshmem server is needed)
>>>      -device ivshmem,shm=nahanni,size=512m,vectors=8,ioeventfd=on

I'm not sure that ioeventfd=on adds anything when no chardev is in
effect, actually.

>> I think<doorbell/>  is a better name than ioeventfd.
> That's a magic name from my p.o.v, because it can indicate any
> boolean options. How should I get it documented? :-)

The "doorbell" element, if present, lets each guest send an interrupt to
other guests.  For the ivshmem model, this requires the path to be
specified and ivshmem_server to be running.


>> That is somewhat
>> kvm-specific, but there's no reason for it to be.
> Being general is the rule to introduce new XML tags, but sometimes
> the better way is to keep it specific. It's not that bad because
> at least we can ensure the specific tag only works for the specific
> driver.

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