Re: [Qemu-devel] [PATCH 5/8] hw: designware: add read memory region callback

[Li Qiang <liq3ea@gmail.com>]

Paolo Bonzini <pbonzini@redhat.com> 于2018年9月13日周四 下午11:12写道：

> On 12/09/2018 18:01, Li Qiang wrote:
> > From: Li Qiang <liq3ea@gmail.com>
> >
> > Signed-off-by: Li Qiang <liq3ea@gmail.com>
> > ---
> >  hw/pci-host/designware.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> >
> > diff --git a/hw/pci-host/designware.c b/hw/pci-host/designware.c
> > index 29ea313798..f5641b5c8c 100644
> > --- a/hw/pci-host/designware.c
> > +++ b/hw/pci-host/designware.c
> > @@ -57,6 +57,12 @@ designware_pcie_root_to_host(DesignwarePCIERoot *root)
> >      return DESIGNWARE_PCIE_HOST(bus->parent);
> >  }
> >
> > +static uint64_t designware_pcie_root_msi_read(void *opaque, hwaddr addr,
> > +                                              unsigned size)
> > +{
> > +    return 0;
> > +}
> > +
> >  static void designware_pcie_root_msi_write(void *opaque, hwaddr addr,
> >                                             uint64_t val, unsigned len)
> >  {
> > @@ -71,6 +77,7 @@ static void designware_pcie_root_msi_write(void
> *opaque, hwaddr addr,
> >  }
> >
> >  static const MemoryRegionOps designware_pci_host_msi_ops = {
> > +    .read = designware_pcie_root_msi_read,
> >      .write = designware_pcie_root_msi_write,
> >      .endianness = DEVICE_LITTLE_ENDIAN,
> >      .valid = {
> >
>
> This probably needs to generate an unassigned access too, because the
> datasheet says that the device basically traps memory writes.
>
> Generating an unassigned access is probably a good idea for the memory
> core; devices can then override the behavior to return zero.  I'm
> queuing patches 1-4, with slightly expanded commit messages.
>
>
Hi Paolo,
Thanks for your review!

These patches has been got a deep discuss, I'm not sure these patches is
necessory.
The discussion can be found in this thread.
-->https://lists.gnu.org/archive/html/qemu-devel/2018-09/msg01391.html


Thanks,
Li Qiang


> Paolo
>