> -----Original Message----- > From: Paolo Bonzini [mailto:pbonz...@redhat.com] > Sent: 09 May 2016 17:39 > To: Paul Durrant; qemu-devel@nongnu.org; xen-de...@lists.xenproject.org > Cc: Stefano Stabellini; Anthony Perard > Subject: Re: [PATCH] xen-hvm: ignore background I/O sections > > > > On 09/05/2016 18:18, Paul Durrant wrote: > > Since Xen will correctly handle accesses to unimplemented I/O ports (by > > returning all 1's for reads and ignoring writes) there is no need for > > QEMU to register backgroud I/O sections. > > > > This patch therefore adds checks to xen_io_add/del so that sections with > > memory-region ops pointing at 'unassigned_io_ops' are ignored. > > > > Signed-off-by: Paul Durrant <paul.durr...@citrix.com> > > Cc: Stefano Stabellini <sstabell...@kernel.org> > > Cc: Anthony Perard <anthony.per...@citrix.com> > > Cc: Paolo Bonzini <pbonz...@redhat.com> > > --- > > xen-hvm.c | 12 ++++++++++-- > > 1 file changed, 10 insertions(+), 2 deletions(-) > > > > diff --git a/xen-hvm.c b/xen-hvm.c > > index 039680a..8ab44f0 100644 > > --- a/xen-hvm.c > > +++ b/xen-hvm.c > > @@ -510,8 +510,12 @@ static void xen_io_add(MemoryListener *listener, > > MemoryRegionSection *section) > > { > > XenIOState *state = container_of(listener, XenIOState, io_listener); > > + MemoryRegion *mr = section->mr; > > > > - memory_region_ref(section->mr); > > + if (mr->ops == &unassigned_io_ops) > > + return; > > Missing braces, same in xen_io_del. Otherwise looks ok. >
Ah, sorry. Forgot to style-switch. Will post v2. > Paolo > > > + memory_region_ref(mr); > > > > xen_map_io_section(xen_xc, xen_domid, state->ioservid, section); > > } > > @@ -520,10 +524,14 @@ static void xen_io_del(MemoryListener *listener, > > MemoryRegionSection *section) > > { > > XenIOState *state = container_of(listener, XenIOState, io_listener); > > + MemoryRegion *mr = section->mr; > > + > > + if (mr->ops == &unassigned_io_ops) > > + return; > > > > xen_unmap_io_section(xen_xc, xen_domid, state->ioservid, section); > > > > - memory_region_unref(section->mr); > > + memory_region_unref(mr); > > } > > > > static void xen_device_realize(DeviceListener *listener, > >