Re: [Qemu-devel] [PATCH] kvm: allow arbitrarily sized mmio ioeventfd

[Avi Kivity <avi@redhat.com>]

On 03/22/2012 03:28 PM, Jan Kiszka wrote:
> On 2012-03-20 13:31, Michael S. Tsirkin wrote:
> > We use a 2 byte ioeventfd for virtio memory,
> > add support for this.
> > 
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > ---
> >  hw/ivshmem.c |    8 ++++----
> >  kvm-all.c    |   15 ++++++++-------
> >  kvm-stub.c   |    2 +-
> >  kvm.h        |    3 ++-
> >  4 files changed, 15 insertions(+), 13 deletions(-)
> > 
> > diff --git a/hw/ivshmem.c b/hw/ivshmem.c
> > index 5ebf840..f02530c 100644
> > --- a/hw/ivshmem.c
> > +++ b/hw/ivshmem.c
> > @@ -354,8 +354,8 @@ static void close_guest_eventfds(IVShmemState *s, int posn)
> >      guest_curr_max = s->peers[posn].nb_eventfds;
> >  
> >      for (i = 0; i < guest_curr_max; i++) {
> > -        kvm_set_ioeventfd_mmio_long(s->peers[posn].eventfds[i],
> > -                    s->mmio_addr + DOORBELL, (posn << 16) | i, 0);
> > +        kvm_set_ioeventfd_mmio(s->peers[posn].eventfds[i],
> > +                    s->mmio_addr + DOORBELL, (posn << 16) | i, 0, 4);
> >          close(s->peers[posn].eventfds[i]);
> >      }
> >  
> > @@ -500,8 +500,8 @@ static void ivshmem_read(void *opaque, const uint8_t * buf, int flags)
> >      }
> >  
> >      if (ivshmem_has_feature(s, IVSHMEM_IOEVENTFD)) {
> > -        if (kvm_set_ioeventfd_mmio_long(incoming_fd, s->mmio_addr + DOORBELL,
> > -                        (incoming_posn << 16) | guest_max_eventfd, 1) < 0) {
> > +        if (kvm_set_ioeventfd_mmio(incoming_fd, s->mmio_addr + DOORBELL,
> > +                        (incoming_posn << 16) | guest_max_eventfd, 1, 4) < 0) {
> >              fprintf(stderr, "ivshmem: ioeventfd not available\n");
> >          }
> >      }
> > diff --git a/kvm-all.c b/kvm-all.c
> > index 42e5e23..bcf0dbe 100644
> > --- a/kvm-all.c
> > +++ b/kvm-all.c
> > @@ -744,10 +744,10 @@ static void kvm_mem_ioeventfd_add(MemoryRegionSection *section,
> >  {
> >      int r;
> >  
> > -    assert(match_data && section->size == 4);
> > +    assert(match_data && section->size <= 8);
>
> Probably nitpicking, but does it also work with non-power-of-two sizes?
>

It won't, but it's hard to generate 3-byte writes (not impossible though).

-- 
error compiling committee.c: too many arguments to function