On 2011-04-28 16:54, Alex Williamson wrote:
> On Thu, 2011-04-28 at 16:46 +0200, Jan Kiszka wrote:
>> On 2011-04-28 16:29, Alex Williamson wrote:
>>> On Thu, 2011-04-28 at 10:59 +0200, Jan Kiszka wrote:
>>>> Use rages_overlap and proper constants to match the access range against
>>> ^^^^^ typo - only if you resend
>>>
>>>> regions that need special handling. This also fixes yet uncaught
>>>> high-byte write access to the command register. Moreover, use more
>>>> constants instead of magic numbers.
>>>>
>>>> Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
>>>> ---
>>>> hw/device-assignment.c | 39 +++++++++++++++++++++++++++++----------
>>>> 1 files changed, 29 insertions(+), 10 deletions(-)
>>>>
>>>> diff --git a/hw/device-assignment.c b/hw/device-assignment.c
>>>> index 606d725..3481c93 100644
>>>> --- a/hw/device-assignment.c
>>>> +++ b/hw/device-assignment.c
>>>> @@ -404,13 +404,20 @@ static void assigned_dev_pci_write_config(PCIDevice *d, uint32_t address,
>>>> return assigned_device_pci_cap_write_config(d, address, val, len);
>>>> }
>>>>
>>>> - if (address == 0x4) {
>>>> + if (ranges_overlap(address, len, PCI_COMMAND, 2)) {
>>>> pci_default_write_config(d, address, val, len);
>>>> /* Continue to program the card */
>>>> }
>>>>
>>>> - if ((address >= 0x10 && address <= 0x24) || address == 0x30 ||
>>>> - address == 0x34 || address == 0x3c || address == 0x3d) {
>>>> + /*
>>>> + * Catch access to
>>>> + * - base address registers
>>>> + * - ROM base address & capability pointer
>>>> + * - interrupt line & pin
>>>> + */
>>>> + if (ranges_overlap(address, len, PCI_BASE_ADDRESS_0, 24) ||
>>>> + ranges_overlap(address, len, PCI_ROM_ADDRESS, 8) ||
>>>
>>> Should this be 5 bytes instead of 8? I'm not sure why we'd add catching
>>> these reserved fields, but not those immediately after this range.
>>
>> Yes, that's asking for clarification: Should we allow direct access to
>> the complete reserved space or virtualize it? Depending on this, the
>> proper value should be 5 or 14 (the latter would also save one
>> ranges_overlap).
>
> I vote for 5 here since a cleanup patch shouldn't have behavior changes
> hidden in it. I don't see any great value in virtualizing reserved
> bits. It seems like it could only make things not work if a vendor was
> stupid enough to hide something in there. Thanks,
Thinking about this and the other sub-dword matches again, there is a
problem in my approach:
I redirect the complete write to the virtualized space once there is an
overlap. So a dword write at PCI_INTERRUPT_LINE would not touch the real
PCI_MIN_GNT & PCI_MAX_LAT. But writing directly to those without overlap
would. The same applies to our reserved space, though this inconsistency
is not critical here - but still undesirable.
Jan
--
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux
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