Re: [Qemu-devel] [Question]Support of China loogson processor

[Leon Alrae <leon.alrae@imgtec.com>]

On 16/04/15 16:17, Paolo Bonzini wrote:
> 
> 
> On 16/04/2015 17:05, Leon Alrae wrote:
>> On 16/04/2015 13:02, Paolo Bonzini wrote:
>>>
>>>
>>> On 16/04/2015 13:07, Leon Alrae wrote:
>>>> Since I also haven't had a chance to test Loongson emulation, I thought
>>>> I'd give it a try (TCG only, Loongson-2E cpu and fulong2e machine).
>>>>
>>>> Good news is that I'm able to get to the login prompt using ancient QEMU
>>>> v1.0, kernel 2.6.33 (with additional patch from
>>>> https://lists.gnu.org/archive/html/qemu-devel/2010-06/msg02566.html) and
>>>> some old debian image I had handy. However, in any newer version
>>>> starting from v1.1.0 of QEMU something goes horribly wrong and it just
>>>> segfaults somewhere inside hw/bonito.c quite early during kernel
>>>> booting.
>>>
>>> Where exactly?  If it's related to the memory API conversion, it may be
>>> easy to fix.  I can look at a backtrace (or you can just put the Debian
>>> image somewhere I can grab it).
>>
>> Bisect points at: 5312bd8b3152f8d4fcf9389ba54e32b09f4b4093
>>
>> Crash occurs during the first access, below there is backtrace from
>> working and not working case:
> 
> This is my best guess...
> 
> diff --git a/hw/pci-host/bonito.c b/hw/pci-host/bonito.c
> index 8bdd569..8134d0b 100644
> --- a/hw/pci-host/bonito.c
> +++ b/hw/pci-host/bonito.c
> @@ -233,7 +233,7 @@ static void bonito_writel(void *opaque, hwaddr addr,
>      uint32_t saddr;
>      int reset = 0;
>  
> -    saddr = (addr - BONITO_REGBASE) >> 2;
> +    saddr = addr >> 2;
>  
>      DPRINTF("bonito_writel "TARGET_FMT_plx" val %x saddr %x\n", addr, val, saddr);
>      switch (saddr) {
> @@ -295,7 +295,7 @@ static uint64_t bonito_readl(void *opaque, hwaddr addr,
>      PCIBonitoState *s = opaque;
>      uint32_t saddr;
>  
> -    saddr = (addr - BONITO_REGBASE) >> 2;
> +    saddr = addr >> 2;
>  
>      DPRINTF("bonito_readl "TARGET_FMT_plx"\n", addr);
>      switch (saddr) {
> 

Nice. Thanks!

Would you send the patch or should I do this? With this fix fulong2e
machine is brought back to life. It would be great to have it in 2.3.

Leon