[Qemu-devel] Re: [PATCH v4 3/3] Inter-VM shared memory PCI device

[Avi Kivity]

On 04/15/2010 02:30 AM, Cam Macdonell wrote:
> > > Sample programs, init scripts and the shared memory server are available
> > > in a
> > > git repo here:
> > >
> > >      www.gitorious.org/nahanni
> > >
> > >        
> > Please consider qemu.git/contrib.
> >      
> Should the compilation be tied into Qemu's regular build with a switch
> (e.g. --enable-ivshmem-server)? Or should it be its own separate
> build?
>    

It can have its own makefile.
> > > ---
> > >   Makefile.target |    3 +
> > >   hw/ivshmem.c    |  700
> > > +++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > >   qemu-char.c     |    6 +
> > >   qemu-char.h     |    3 +
> > >
> > >        
> > qemu-doc.texi | 45 +++++++++++++
> >      
> Seems to be light on qdev devices.  I notice there is a section named
> "Data Type Index" that "could be used for qdev device names and
> options", but is currently empty.  Should I place documentation there
> of device there or just add it to "3.3 Invocation"?
>    

I think those are in qemu-options.hx.  Just put it somewhere where it 
seems appropriate.

>    
> >      
> > >   4 files changed, 712 insertions(+), 0 deletions(-)
> > >   create mode 100644 hw/ivshmem.c
> > >
> > > diff --git a/Makefile.target b/Makefile.target
> > > index 1ffd802..bc9a681 100644
> > > --- a/Makefile.target
> > > +++ b/Makefile.target
> > > @@ -199,6 +199,9 @@ obj-$(CONFIG_USB_OHCI) += usb-ohci.o
> > >   obj-y += rtl8139.o
> > >   obj-y += e1000.o
> > >
> > > +# Inter-VM PCI shared memory
> > > +obj-y += ivshmem.o
> > > +
> > >
> > >        
> > depends on CONFIG_PCI
> >      
> as in
>
> obj-($CONFIG_PCI) += ivshmem.o
>
>
> the variable CONFIG_PCI doesn't seem to be set during configuration.
> I don't see any other PCI devices that depend on it.

My mistake, keep as is.

> Do we also want
> to depend on CONFIG_KVM?
>    

No real need.

> > > +static void create_shared_memory_BAR(IVShmemState *s, int fd) {
> > > +
> > > +    s->shm_fd = fd;
> > > +
> > > +    s->ivshmem_offset = qemu_ram_mmap(s->shm_fd, s->ivshmem_size,
> > > +             MAP_SHARED, 0);
> > >
> > >        
> > Where did the offset go?
> >      
> 0 is the offset.  I include the offset parameter in qemu_ram_mmap() to
> make it flexible for other uses.

Makes sense.

> Are you suggesting to take an
> optional offset as an argument to -device?
>    

No need.

--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.