Re: [Xen-devel] [PATCH v2] qemu/xen: Add 64 bits big bar support on qemu

["Hao, Xudong" <xudong.hao@xxxxxxxxx>]

> -----Original Message-----
> From: Stefano Stabellini [mailto:stefano.stabellini@xxxxxxxxxxxxx]
> Sent: Wednesday, September 26, 2012 6:57 PM
> To: Hao, Xudong
> Cc: Stefano Stabellini; xen-devel@xxxxxxxxxxxxx; qemu-devel@xxxxxxxxxx;
> Zhang, Xiantao
> Subject: RE: [PATCH v2] qemu/xen: Add 64 bits big bar support on qemu
> 
> > Will change to:
> > -        if (r->type & XEN_HOST_PCI_REGION_TYPE_IO) {
> > +        if (r->type & XEN_HOST_PCI_REGION_TYPE_IO)
> >              type = PCI_BASE_ADDRESS_SPACE_IO;
> > -        } else {
> > +        else
> >              type = PCI_BASE_ADDRESS_SPACE_MEMORY;
> > -            if (r->type & XEN_HOST_PCI_REGION_TYPE_PREFETCH) {
> > +            if (r->type & XEN_HOST_PCI_REGION_TYPE_MEM_64)
> > +                type |= PCI_BASE_ADDRESS_MEM_TYPE_64;
> > +           else if (r->type & XEN_HOST_PCI_REGION_TYPE_PREFETCH)
> >                  type |= PCI_BASE_ADDRESS_MEM_PREFETCH;
> > -            }
> > -        }
> 
> Isn't it possible that both XEN_HOST_PCI_REGION_TYPE_MEM_64 and
> XEN_HOST_PCI_REGION_TYPE_PREFETCH are set? It doesn't look like this can
> cover that case.
It's possible. Thanks comments.

> The following seems to be what you are looking for:
> 
> 
> if (r->type & XEN_HOST_PCI_REGION_TYPE_IO) {
>     type = PCI_BASE_ADDRESS_SPACE_IO;
> } else {
>     type = PCI_BASE_ADDRESS_SPACE_MEMORY;
>     if (r->type & XEN_HOST_PCI_REGION_TYPE_PREFETCH) {
>         type |= PCI_BASE_ADDRESS_MEM_PREFETCH;
>     }
>     if (r->type & XEN_HOST_PCI_REGION_TYPE_MEM_64) {
>         type |= PCI_BASE_ADDRESS_MEM_TYPE_64;
>     }
> }
> 
> 
> > > >  static XenPTBarFlag xen_pt_bar_reg_parse(XenPCIPassthroughState
> *s,
> > > >                                           XenPTRegInfo *reg)
> > > >  {
> > > > @@ -366,7 +367,7 @@ static XenPTBarFlag
> > > xen_pt_bar_reg_parse(XenPCIPassthroughState *s,
> > > >
> > > >      /* check unused BAR */
> > > >      r = &d->io_regions[index];
> > > > -    if (r->size == 0) {
> > > > +    if (!xen_pt_get_bar_size(r)) {
> > > >          return XEN_PT_BAR_FLAG_UNUSED;
> > > >      }
> > > >
> > > > @@ -383,6 +384,24 @@ static XenPTBarFlag
> > > xen_pt_bar_reg_parse(XenPCIPassthroughState *s,
> > > >      }
> > > >  }
> > > >
> > > > +static bool is_64bit_bar(PCIIORegion *r)
> > > > +{
> > > > +    return !!(r->type & PCI_BASE_ADDRESS_MEM_TYPE_64);
> > > > +}
> > > > +
> > > > +static uint64_t xen_pt_get_bar_size(PCIIORegion *r)
> > > > +{
> > > > +    if (is_64bit_bar(r))
> > > > +    {
> > > > +        uint64_t size64;
> > > > +        size64 = (r + 1)->size;
> > > > +        size64 <<= 32;
> > > > +        size64 += r->size;
> > > > +        return size64;
> > > > +    }
> > > > +    return r->size;
> > > > +}
> > > > +
> > > >  static inline uint32_t base_address_with_flags(XenHostPCIIORegion
> *hr)
> > > >  {
> > > >      if (hr->type & XEN_HOST_PCI_REGION_TYPE_IO) {
> > > > @@ -481,7 +500,10 @@ static int
> > > xen_pt_bar_reg_write(XenPCIPassthroughState *s, XenPTReg *cfg_entry,
> > > >      switch (s->bases[index].bar_flag) {
> > > >      case XEN_PT_BAR_FLAG_MEM:
> > > >          bar_emu_mask = XEN_PT_BAR_MEM_EMU_MASK;
> > > > -        bar_ro_mask = XEN_PT_BAR_MEM_RO_MASK | (r_size - 1);
> > > > +        if (!r_size)
> > > > +            bar_ro_mask = XEN_PT_BAR_ALLF;
> > > > +        else
> > > > +            bar_ro_mask = XEN_PT_BAR_MEM_RO_MASK | (r_size -
> 1);
> > > >          break;
> > >
> > > Is this an actual mistake everywhere?
> >
> > It's low 32bit mask for 64 bit bars.
> 
> I see. It is a good idea to add a line of comment in the code saying
> that.

OK, I'll add code comment.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel