| Message ID | 1462811363-16219-1-git-send-email-paul.durrant@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
> -----Original Message----- > From: Paul Durrant [mailto:paul.durrant@citrix.com] > Sent: 09 May 2016 17:29 > To: qemu-devel@nongnu.org; xen-devel@lists.xenproject.org > Cc: Paul Durrant; Stefano Stabellini; Anthony Perard; Paolo Bonzini > Subject: [PATCH v2] xen-hvm: ignore background I/O sections > > 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.durrant@citrix.com> > Cc: Stefano Stabellini <sstabellini@kernel.org> > Cc: Anthony Perard <anthony.perard@citrix.com> > Cc: Paolo Bonzini <pbonzini@redhat.com> > --- > > v2: > - Add missing braces Aargh. Forgot to git add. Please ignore. Paul > --- > 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; > + > + 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, > -- > 2.1.4
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; + + 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,
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.durrant@citrix.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Anthony Perard <anthony.perard@citrix.com> Cc: Paolo Bonzini <pbonzini@redhat.com> --- v2: - Add missing braces --- xen-hvm.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)