Re: [Qemu-devel] [PATCH] Make rtl8139 network interface card compatible with Mac OS 10.4

[Programmingkid]

On Dec 30, 2015, at 9:03 AM, Mark Cave-Ayland wrote:

> On 30/12/15 00:35, Programmingkid wrote:
> 
>> On Dec 29, 2015, at 7:05 PM, Programmingkid wrote:
>> 
>>> 
>>> On Dec 29, 2015, at 4:04 PM, Mark Cave-Ayland wrote:
>>> 
>>>> On 29/12/15 17:59, Programmingkid wrote:
>>>> 
>>>>> This patch solves the few problems that needed to be solved in order for a
>>>>> Mac OS 10.4 guest to use the rtl8139 nic. 
>>>>> 
>>>>> The pci_dma_read() function would only return zero when a MemoryRegion 
>>>>> object
>>>>> was not enabled. Enabling the object makes the pci_dma_read() function 
>>>>> work
>>>>> correctly.
>>>>> 
>>>>> The Linux rtl8139 driver needs base address register zero set to PIO. This
>>>>> conflicts with Mac OS 10.4's driver needing base address register zero 
>>>>> set to
>>>>> MMIO. So a macro has been added that allows the user to decide which 
>>>>> operating
>>>>> system this network interface card will be compatible with. Note: Windows 
>>>>> XP's
>>>>> driver works regardless of the macro setting.
>>>>> 
>>>>> Signed-off-by: John Arbuckle <address@hidden>
>>>>> 
>>>>> ---
>>>>> hw/net/rtl8139.c     |   15 ++++++++++++++-
>>>>> include/hw/pci/pci.h |    1 +
>>>>> 2 files changed, 15 insertions(+), 1 deletions(-)
>>>>> 
>>>>> diff --git a/hw/net/rtl8139.c b/hw/net/rtl8139.c
>>>>> index 90ef72b..e17a471 100644
>>>>> --- a/hw/net/rtl8139.c
>>>>> +++ b/hw/net/rtl8139.c
>>>>> @@ -64,6 +64,14 @@
>>>>> /* debug RTL8139 card */
>>>>> //#define DEBUG_RTL8139 1
>>>>> 
>>>>> +/*
>>>>> + * The driver that ships with Mac OS 10.4 has to have its base address 
>>>>> register
>>>>> + * 0 set to MMIO space. This directly conflicts with the Linux driver 
>>>>> that
>>>>> + * needs the PIO set to base address register 0. Mac OS 10.5 or higher 
>>>>> does not
>>>>> + * need this macro set.
>>>>> + */
>>>>> +/* #define MAC_OS_10_4_DRIVER_COMPATIBILITY 1 */
>>>>> +
>>>>> #define PCI_PERIOD 30    /* 30 ns period = 33.333333 Mhz frequency */
>>>>> 
>>>>> #define SET_MASKED(input, mask, curr) \
>>>>> @@ -3444,9 +3452,14 @@ static void pci_rtl8139_realize(PCIDevice *dev, 
>>>>> Error **errp)
>>>>>                         "rtl8139", 0x100);
>>>>>   memory_region_init_io(&s->bar_mem, OBJECT(s), &rtl8139_mmio_ops, s,
>>>>>                         "rtl8139", 0x100);
>>>>> +
>>>>> +#ifdef MAC_OS_10_4_DRIVER_COMPATIBILITY
>>>>> +    pci_register_bar(dev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY, &s->bar_mem);
>>>>> +    pci_register_bar(dev, 1, PCI_BASE_ADDRESS_SPACE_IO, &s->bar_io);
>>>>> +#else
>>>>>   pci_register_bar(dev, 0, PCI_BASE_ADDRESS_SPACE_IO, &s->bar_io);
>>>>>   pci_register_bar(dev, 1, PCI_BASE_ADDRESS_SPACE_MEMORY, &s->bar_mem);
>>>>> -
>>>>> +#endif
>>>>>   qemu_macaddr_default_if_unset(&s->conf.macaddr);
>>>>> 
>>>>>   /* prepare eeprom */
>>>>> diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
>>>>> index 379b6e1..8e95c75 100644
>>>>> --- a/include/hw/pci/pci.h
>>>>> +++ b/include/hw/pci/pci.h
>>>>> @@ -699,6 +699,7 @@ static inline int pci_dma_rw(PCIDevice *dev, 
>>>>> dma_addr_t addr,
>>>>> static inline int pci_dma_read(PCIDevice *dev, dma_addr_t addr,
>>>>>                              void *buf, dma_addr_t len)
>>>>> {
>>>>> +    memory_region_set_enabled(&dev->bus_master_enable_region, true);
>>>>>   return pci_dma_rw(dev, addr, buf, len, DMA_DIRECTION_TO_DEVICE);
>>>>> }
>>>> 
>>>> Can you provide more information about how you tested this patch? 
>> 
>> I would add printf statements to the functions that would be called in the 
>> RTL8139.c file when the driver is ran. The functions are these: 
>> rtl8139_io_writel(), rtl8139_io_readb(), rtl8139_io_readw(), 
>> rtl8139_io_readl(). The printf statements would print the register "addr" 
>> used and its value. 
>> 
>> The driver had its debug macro set when I compiled it, so I would see what 
>> functions were called.
>> 
>> In the driver's outputPacket() function, I used a loop to print out all the 
>> raw packet data that was being sent to the nic. In the first row was the MAC 
>> address of the nic, so I know the data was not junk. I added a loop to the 
>> rtl8139.c file in the rtl8139_transmit_one() function that would also print 
>> the raw packet data. The data from the driver loop would be hexadecimal 
>> numbers, and usually all zeros in the rtl8139.c file's loop. That is how I 
>> knew there was a communication's error. 
>> 
>> After a lot of stepping thru code using gdb, I found out that a 
>> MemoryRegions's enabled member variable was set to false, causing a zero 
>> value being returned every time. When I set the value to true, that is when 
>> the magic started happening. For the first time, data between the driver and 
>> the emulated nic matched. It didn't take me too long to figure out where to 
>> put the code needed to make communications possible.
>> 
>> I would build the Mac OS X driver inside of QEMU using Mac OS 10.4 as a 
>> guest. I used XCode to build the driver. To run the driver I used these 
>> commands:
>> 
>> "sudo su" once to go into root.
>> cp -R <path to xcode build directory>/AppleRTL8139.kext /tmp
>> kextload /tmp/AppleRTL8139.kext
>> Then review all the debug text I would see in the Console application.  
>> kextunload /tmp/AppleRTL8139.kext  - unload the driver so I could test more 
>> changes without rebooting.
>> 
>> I would sometimes go into the Network Pane inside of the System Preferences 
>> to see if the nic was working. After a lot of hard work, I was able to watch 
>> a YouTube video inside of QEMU with this patch applied.
> 
> That's great detective work! As Zoltan mentioned in your other thread,
> what you're doing with the memory_region_set_enabled() call is the same
> as enabling bus mastering on the card, so can you try removing it from
> the patch and testing against an OpenBIOS with this patch applied
> instead:
> http://www.openfirmware.info/pipermail/openbios/2014-June/008448.html.

I did disable the change I made to the pci_dma_read() function and applied this
patch to OpenBIOS. It makes Mac OS X stop booting. This is the message it is
stuck at when Zoltan's patch is applied:
mig_table_max_displ = 70

I even removed the rtl8139 from QEMU's options and Mac OS X still stopped 
booting
at the same exact spot. 

> It looks like we have to face up to the reality that Apple's OF
> implementation likes to enable bus mastering for some cards and emulate
> this behaviour in OpenBIOS, since because of this some drivers don't
> explicitly enable bus mastering and so fail under emulation.
> 
> I'll go back and revisit Zoltan's patches to see if we can come up with
> something that works better for OpenBIOS upstream. In the meantime I
> still can't quite work out why you still need to swap the BARs around as
> AFAICT both the mmio and io BARs are mapped onto the chip registers -
> any chance you could add some debugging to QEMU in order to figure out
> what is going wrong without your patch?

I have done a lot of debugging. With only the pci_dma_read() change applied to 
QEMU, nothing the Mac OS X driver does ever accesses any of the functions from 
the rtl8139.c file (as far as I can tell). I will add that when this code "if ( 
csrRead8( RTL_CM ) & R_CM_RST )" is executed by the driver, the value is 16. It 
appeared to be pretty consistent. The value returned by just "csrRead8( RTL_CM 
)" is 24.