[Qemu-devel] Re: [PATCH 21/25] pci: make bar update function aware of pci bridge.

[Michael S. Tsirkin]

On Mon, Oct 05, 2009 at 06:47:39PM +0900, Isaku Yamahata wrote:
> On Sun, Oct 04, 2009 at 12:53:45PM +0200, Michael S. Tsirkin wrote:
> > On Sat, Oct 03, 2009 at 05:16:13AM +0900, Isaku Yamahata wrote:
> > > header type of 01 has differenct BAR to type 00.
> > > It has only BAR0,1 and expantion rom whose offset address
> > > is different from type 00 one.
> > 
> > There are some typos in the comment
> > 
> > > Signed-off-by: Isaku Yamahata <address@hidden>
> > > ---
> > >  hw/pci.c |   66 
> > > +++++++++++++++++++++++++++++++++++++++++++++++++++----------
> > >  hw/pci.h |    1 +
> > >  2 files changed, 56 insertions(+), 11 deletions(-)
> > > 
> > > diff --git a/hw/pci.c b/hw/pci.c
> > > index ed9b785..b708d71 100644
> > > --- a/hw/pci.c
> > > +++ b/hw/pci.c
> > > @@ -498,6 +498,35 @@ int pci_unregister_device(PCIDevice *pci_dev)
> > >      return 0;
> > >  }
> > >  
> > > +#define PCI_BAR_INVALID  UINT32_MAX
> > 
> > Just use -1 to report error.
> > 
> > > +static uint32_t pci_bar_config_offset(PCIDevice *d, int region_num)
> > 
> > Why uint32_t? I think it should be just int.
> > Please add small comment documenting what function does.
> > 
> > > +{
> > 
> > This functions does too much sanity checking, which is where
> > all the complexity comes from.  It's not the best place to do
> > sanity checking: do it when adding region, if you must.
> > 
> > So this should be simply:
> > 
> > static int pci_bar_config_offset(PCIDevice *d, int region_num)
> > {
> >     if (region_num != PCI_ROM_ADDRESS)
> >             return PCI_BASE_ADDRESS_0 + region_num * 4;
> > 
> >     return (d->config[PCI_HEADER_TYPE] & PCI_HEADER_TYPE_BRIDGE) ?
> >             PCI_ROM_ADDRESS : PCI_BRIDGE_ROM_ADDRESS;
> > }
> > 
> > 
> > > +    switch (d->config[PCI_HEADER_TYPE] & 
> > > ~PCI_HEADER_TYPE_MULTI_FUNCTION) {
> > > +    case PCI_HEADER_TYPE_NORMAL:
> > > +        /* BAR 0-5 and Expantion ROM*/
> > 
> > Nit: space before */
> > 
> > > +        if (region_num < PCI_ROM_SLOT) {
> > > +            return PCI_BASE_ADDRESS_0 + region_num * 4;
> > > +        } else if (region_num == PCI_ROM_SLOT) {
> > > +            return PCI_ROM_ADDRESS;
> > > +        }
> > > +        break;
> > > +    case PCI_HEADER_TYPE_BRIDGE:
> > > +        /* BAR 0-1 and Expantion ROM */
> > 
> > typo
> > 
> > > +        if (region_num < 2) {
> > 
> > what's 2?
> > 
> > > +            return PCI_BASE_ADDRESS_0 + region_num * 4;
> > > +        } else if (region_num == PCI_ROM_SLOT) {
> > > +            return PCI_ROM_ADDRESS1;
> > > +        }
> > > +        break;
> > > +    case PCI_HEADER_TYPE_CARDBUS:
> > 
> > the last line is useless
> > 
> > > +    default:
> > > +        break;
> > > +    }
> > > +    fprintf(stderr, "ERROR: %s: unknow PCI config header type %d or bar 
> > > %d\n",
> > > +            __func__, d->config[PCI_HEADER_TYPE], region_num);
> > > +    return PCI_BAR_INVALID;
> > 
> > Caller does not seem to check PCI_BAR_INVALID.
> > 
> > > +}
> > > +
> > >  void pci_register_bar(PCIDevice *pci_dev, int region_num,
> > >                              pcibus_t size, int type,
> > >                              PCIMapIORegionFunc *map_func)
> > > @@ -521,13 +550,11 @@ void pci_register_bar(PCIDevice *pci_dev, int 
> > > region_num,
> > >      r->type = type;
> > >      r->map_func = map_func;
> > >  
> > > +    addr = pci_bar_config_offset(pci_dev, region_num);
> > >      wmask = ~(size - 1);
> > >      if (region_num == PCI_ROM_SLOT) {
> > > -        addr = 0x30;
> > >          /* ROM enable bit is writeable */
> > >          wmask |= PCI_ROM_ADDRESS_ENABLE;
> > > -    } else {
> > > -        addr = 0x10 + region_num * 4;
> > >      }
> > >      pci_set_long(pci_dev->config + addr, type);
> > >      if (pci_bar_is_64bit(r)) {
> > > @@ -549,11 +576,9 @@ static void pci_update_mappings(PCIDevice *d)
> > >      cmd = pci_get_word(d->config + PCI_COMMAND);
> > >      for(i = 0; i < PCI_NUM_REGIONS; i++) {
> > >          r = &d->io_regions[i];
> > > -        if (i == PCI_ROM_SLOT) {
> > > -            config_ofs = 0x30;
> > > -        } else {
> > > -            config_ofs = 0x10 + i * 4;
> > > -        }
> > > +
> > 
> > kill extra empty line
> > 
> > > +        config_ofs = pci_bar_config_offset(d, i);
> > > +
> > >          if (r->size != 0) {
> > >              if (r->type & PCI_ADDRESS_SPACE_IO) {
> > >                  if (cmd & PCI_COMMAND_IO) {
> > > @@ -1133,10 +1158,29 @@ static void pci_bridge_write_config(PCIDevice *d,
> > >                               uint32_t address, uint32_t val, int len)
> > >  {
> > >      PCIBridge *s = (PCIBridge *)d;
> > > +    PCIBus *bus = s->bus;
> > > +    uint8_t *orig = pci_write_config_init(d, address, len);
> > > +
> > > +    pci_default_write_config_common(d, address, val, len);
> > >  
> > > -    pci_default_write_config(d, address, val, len);
> > > -    s->bus->bus_num = d->config[PCI_SECONDARY_BUS];
> > > -    s->bus->sub_bus = d->config[PCI_SUBORDINATE_BUS];
> > > +    if (pci_config_changed(orig, d->config, address, len,
> > > +                           PCI_BASE_ADDRESS_0, PCI_BASE_ADDRESS_2 + 4) ||
> > > +        pci_config_changed_with_size(orig, d->config, address, len,
> > > +                                     PCI_ROM_ADDRESS1, 4) ||
> > > +        pci_config_changed_with_size(orig, d->config, address, len,
> > > +                                     PCI_COMMAND, 1)) {
> > > +        pci_update_mappings(d);
> > > +    }
> > > +    if (pci_config_changed_with_size(orig, d->config, address, len,
> > > +                                     PCI_SECONDARY_BUS, 1)) {
> > > +        bus->bus_num = d->config[PCI_SECONDARY_BUS];
> > > +    }
> > > +    if (pci_config_changed_with_size(orig, d->config, address, len,
> > > +                                     PCI_SECONDARY_BUS, 1)) {
> > > +        bus->sub_bus = d->config[PCI_SUBORDINATE_BUS];
> > > +    }
> > 
> > So simply
> > d->config[PCI_SUBORDINATE_BUS] != orig[PCI_SUBORDINATE_BUS]
> > would be enough if we keep orig and config in sync
> > as I suggested in my previous post.
> > 
> > > +
> > > +    pci_write_config_done(orig);
> > >  }
> > >  
> > >  PCIBus *pci_find_bus(PCIBus *bus, int bus_num)
> > > diff --git a/hw/pci.h b/hw/pci.h
> > > index f19b7a8..645dacd 100644
> > > --- a/hw/pci.h
> > > +++ b/hw/pci.h
> > > @@ -174,6 +174,7 @@ static inline int pci_bar_is_64bit(const PCIIORegion 
> > > *r)
> > >  
> > >  /* Header type 1 (PCI-to-PCI bridges) */
> > >  #define PCI_SUBORDINATE_BUS     0x1a    /* Highest bus number behind the 
> > > bridge */
> > > +#define PCI_ROM_ADDRESS1        0x38    /* Same as PCI_ROM_ADDRESS, but 
> > > for htype 1 */
> > 
> > PCI_BRIDGE_ROM_ADDRESS would be clearer.
> > Also don't mix your own macros and ones imported from pci_regs.h
> 
> Unfortunately PCI_ROM_ADDRESS1 is the one defined in pci_regs.h.
> So PCI_ROM_ADDRESS1 is reasonable.

You are right. Sorry about the noise.

> 
> > >  /* Size of the standard PCI config header */
> > >  #define PCI_CONFIG_HEADER_SIZE 0x40
> > 
> 
> -- 
> yamahata