Re: [Qemu-devel] ppc vga output breakage since commit c3c1bb99

[Paolo Bonzini <pbonzini@redhat.com>]

On 01/04/2015 00:34, Mark Cave-Ayland wrote:
> On 30/03/15 12:47, Paolo Bonzini wrote:
> 
>> On 30/03/2015 13:45, Peter Crosthwaite wrote:
>>> Can the address_space_translate_address() length clamp be made
>>> conditional on non-MMIO access as the RC fix? I submitted
>>> c3c1bb99d1c11978d9ce94d1bdcf0705378c1459 as I think its the right
>>> thing to do regardless of memory type, but in reality it only fixes a
>>> bug I encountered with RAM memory regions. The original code ignores
>>> address_space_translate_internal() return-by-pointer length value
>>> absolutely and the new code uses it absolutely. Should we just if the
>>> whole thing, old vs new behaviour on MMIO vs non-MMIO?
>>>
>>> Happy to submit that fixup if that's the accepted plan.
>>
>> I submitted what I think is the right fix (sorry Mark for misspelling
>> your email address).  I think you're patch is correct, so I'd rather not
>> introduce hacks for the release; we can either revert it, or fix ioport.c.
> 
> Ah wait a second - the same patch c3c1bb99 also breaks reset on SPARC32:
> 
> $ ./qemu-system-sparc -prom-env 'auto-boot?=false' -nographic
> Configuration device id QEMU version 1 machine id 32
> Probing SBus slot 0 offset 0
> Probing SBus slot 1 offset 0
> Probing SBus slot 2 offset 0
> Probing SBus slot 3 offset 0
> Probing SBus slot 4 offset 0
> Probing SBus slot 5 offset 0
> Invalid FCode start byte
> CPUs: 1 x FMI,MB86904
> UUID: 00000000-0000-0000-0000-000000000000
> Welcome to OpenBIOS v1.1 built on Mar 12 2015 08:08
>   Type 'help' for detailed information
> 
> 0 > reset-all Unhandled Exception 0x00000029
> PC = 0xffd10c08 NPC = 0xffd10c0c
> Stopping execution
> 
> The reset is controlled by writing a 1 to the hardware reset register at
> physical address 0x71f00000 (system-control according to "info mtree")
> which is handled in hw/misc/slavio_misc.c.
> 
> Given that SYSCTRL_SIZE isn't used at all (and the access size for
> slavio_led_mem_ops also looks wrong), the following seems to be the
> correct fix for the reset and LED access:
> 
> 
> --- a/hw/misc/slavio_misc.c
> +++ b/hw/misc/slavio_misc.c
> @@ -68,6 +68,7 @@ typedef struct APCState {
>  } APCState;
> 
>  #define MISC_SIZE 1
> +#define LED_SIZE 2
>  #define SYSCTRL_SIZE 4
> 
>  #define AUX1_TC        0x02
> @@ -452,13 +453,13 @@ static int slavio_misc_init1(SysBusDevice *sbd)
>      /* 16 bit registers */
>      /* ss600mp diag LEDs */
>      memory_region_init_io(&s->led_iomem, OBJECT(s), &slavio_led_mem_ops, s,
> -                          "leds", MISC_SIZE);
> +                          "leds", LED_SIZE);
>      sysbus_init_mmio(sbd, &s->led_iomem);
> 
>      /* 32 bit registers */
>      /* System control */
>      memory_region_init_io(&s->sysctrl_iomem, OBJECT(s),
> &slavio_sysctrl_mem_ops, s,
> -                          "system-control", MISC_SIZE);
> +                          "system-control", SYSCTRL_SIZE);
>      sysbus_init_mmio(sbd, &s->sysctrl_iomem);
> 
>      /* AUX 1 (Misc System Functions) */
> 
> 
> Then again it is getting quite late in the release cycle...

Yes, it's better to revert for now.  Can you submit the patch above, so
I include it in 2.4 and keep bisectability?

Paolo