Re: [Qemu-devel] [PATCH] try to implement complete pci-to-pci bridge emulator.

["M. Warner Losh" <imp@bsdimp.com>]

In message: <1241170436-2800-5-git-send-email-yamahata@valinux.co.jp>
            Isaku Yamahata <yamahata@valinux.co.jp> writes:
: Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
: ---
:  hw/pci.c      |  175 +++++++++++++++++++++++++++++++++++++++------------------
:  hw/pci.h      |   30 ++++++++++
:  hw/unin_pci.c |    2 +-
:  3 files changed, 151 insertions(+), 56 deletions(-)
: 
: diff --git a/hw/pci.c b/hw/pci.c
: index 0be3662..a1123cb 100644
: --- a/hw/pci.c
: +++ b/hw/pci.c
...
: +        case 0x01:
: +        case 0x02:
: +        case 0x03:
: +        case 0x06:
: +        case 0x07:
: +        case 0x08:
: +        case 0x09:
: +        case 0x0a:
: +        case 0x0b:
: +        case 0x0e:
: +        case 0x10 ... 0x27: /* base */

This is wrong.  BARs are writable, and must be writable to determine
their size.

: +        case 0x2c ... 0x2f: /* read-only subsystem ID & vendor ID */
: +        case 0x30 ... 0x33: /* rom */

This is wrong too.  You have to be able to turn on and off this
mapping by writing bit 0.

: +        case 0x3d:
: +            can_write = 0;
:              break;

General comment: hard coded magic numbers like the above are very hard
to read.

Warner