Re: [Qemu-devel] [Qemu-discuss] error - Guest has not initialized the display yet.

Re: [Qemu-devel] [Qemu-discuss] error - Guest has not initialized the display yet.

[Programmingkid]

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On Mar 25, 2015, at 6:20 PM, qemu-discuss-request@nongnu.org wrote:

>> QEMU window opens up, but I am getting this error "Guest has not initialized
>> the display yet"
>> I had enabled -sdl option while configuring qemu, but I am still getting
>> that error.
> 
> This isn't an error. It is just QEMU telling you that the guest OS
> has not yet done what it needs to do to turn on the emulated graphics
> card and display output.


I'm seeing this error also. When I try to boot Mac OS 10.2 in qemu-system-ppc, I just see a black window. When I switch from the monitor to the vga window, then I see "Guest has not initialized the display (yet)". It doesn't go away. OpenBIOS can't even be accessed anymore. I think I started seeing this problem around the 18th of March. I'm using Mac OS 10.6 as my host. 

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Re: [Qemu-devel] [Qemu-discuss] error - Guest has not initialized the display yet.

[Peter Maydell]

On 25 March 2015 at 23:52, Programmingkid <programmingkidx@gmail.com> wrote:
> I'm seeing this error also.

It's still not an error.

> When I try to boot Mac OS 10.2 in
> qemu-system-ppc, I just see a black window. When I switch from the monitor
> to the vga window, then I see "Guest has not initialized the display (yet)".
> It doesn't go away. OpenBIOS can't even be accessed anymore. I think I
> started seeing this problem around the 18th of March. I'm using Mac OS 10.6
> as my host.

Your symptoms are entirely different, and you have a different bug.

-- PMM

Re: [Qemu-devel] [Qemu-discuss] error - Guest has not initialized the display yet.

[Mark Cave-Ayland]

On 25/03/15 23:52, Programmingkid wrote:

(Added Peter C as CC)

> On Mar 25, 2015, at 6:20 PM, qemu-discuss-request@nongnu.org
> <mailto:qemu-discuss-request@nongnu.org> wrote:
> 
>>> QEMU window opens up, but I am getting this error "Guest has not
>>> initialized
>>> the display yet"
>>> I had enabled -sdl option while configuring qemu, but I am still getting
>>> that error.
>>
>> This isn't an error. It is just QEMU telling you that the guest OS
>> has not yet done what it needs to do to turn on the emulated graphics
>> card and display output.
> 
> I'm seeing this error also. When I try to boot Mac OS 10.2 in
> qemu-system-ppc, I just see a black window. When I switch from the
> monitor to the vga window, then I see "Guest has not initialized the
> display (yet)". It doesn't go away. OpenBIOS can't even be accessed
> anymore. I think I started seeing this problem around the 18th of March.
> I'm using Mac OS 10.6 as my host. 

I've just done some testing here and I see exactly the same issue -
something is preventing OpenBIOS from executing. A quick session with
git bisect points to the following:


c3c1bb99d1c11978d9ce94d1bdcf0705378c1459 is the first bad commit
commit c3c1bb99d1c11978d9ce94d1bdcf0705378c1459
Author: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Date:   Mon Mar 16 22:35:54 2015 -0700

    exec: Respect as_tranlsate_internal length clamp

    address_space_translate_internal will clamp the *plen length argument
    based on the size of the memory region being queried. The iommu walker
    logic in addresss_space_translate was ignoring this by discarding the
    post fn call value of *plen. Fix by just always using *plen as the
    length argument throughout the fn, removing the len local variable.

    This fixes a bootloader bug when a single elf section spans multiple
    QEMU memory regions.

    Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
    Message-Id:
<1426570554-15940-1-git-send-email-peter.crosthwaite@xilinx.com>
    Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>


Reproduction is easy with the command line given below:

  ./qemu-system-ppc -prom-env 'auto-boot?=false'


ATB,

Mark.

Re: [Qemu-devel] [Qemu-discuss] error - Guest has not initialized the display yet.

[Peter Maydell]

On 26 March 2015 at 20:31, Mark Cave-Ayland
<mark.cave-ayland@ilande.co.uk> wrote:
> I've just done some testing here and I see exactly the same issue -
> something is preventing OpenBIOS from executing. A quick session with
> git bisect points to the following:
>
>
> c3c1bb99d1c11978d9ce94d1bdcf0705378c1459 is the first bad commit
> commit c3c1bb99d1c11978d9ce94d1bdcf0705378c1459
> Author: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
> Date:   Mon Mar 16 22:35:54 2015 -0700
>
>     exec: Respect as_tranlsate_internal length clamp
>
>     address_space_translate_internal will clamp the *plen length argument
>     based on the size of the memory region being queried. The iommu walker
>     logic in addresss_space_translate was ignoring this by discarding the
>     post fn call value of *plen. Fix by just always using *plen as the
>     length argument throughout the fn, removing the len local variable.
>
>     This fixes a bootloader bug when a single elf section spans multiple
>     QEMU memory regions.
>
>     Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
>     Message-Id:
> <1426570554-15940-1-git-send-email-peter.crosthwaite@xilinx.com>
>     Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>
>
> Reproduction is easy with the command line given below:
>
>   ./qemu-system-ppc -prom-env 'auto-boot?=false'

I feel like we're recapitulating history here -- is
c3c1bb99d undoing the fix that a87f39543a made for when we
tried this a year ago in 360e607, or is there something
more subtle going on ?

-- PMM

Re: [Qemu-devel] [Qemu-discuss] error - Guest has not initialized the display yet.

[Paolo Bonzini]

On 26/03/2015 21:55, Peter Maydell wrote:
> I feel like we're recapitulating history here -- is
> c3c1bb99d undoing the fix that a87f39543a made for when we
> tried this a year ago in 360e607, or is there something
> more subtle going on ?

It's more subtle.  The patch should only make a difference when
address_space_translate_internal modifies *plen.

The crux of the change is the first operand of this MIN:

-        len = MIN(len, (addr | iotlb.addr_mask) - addr + 1);
+        *plen = MIN(*plen, (addr | iotlb.addr_mask) - addr + 1);

changing from len to *plen.

Paolo

Re: [Qemu-devel] [Qemu-discuss] error - Guest has not initialized the display yet.

[Programmingkid]

On Mar 26, 2015, at 4:31 PM, Mark Cave-Ayland wrote:

> On 25/03/15 23:52, Programmingkid wrote:
> 
> (Added Peter C as CC)
> 
>> On Mar 25, 2015, at 6:20 PM, qemu-discuss-request@nongnu.org
>> <mailto:qemu-discuss-request@nongnu.org> wrote:
>> 
>>>> QEMU window opens up, but I am getting this error "Guest has not
>>>> initialized
>>>> the display yet"
>>>> I had enabled -sdl option while configuring qemu, but I am still getting
>>>> that error.
>>> 
>>> This isn't an error. It is just QEMU telling you that the guest OS
>>> has not yet done what it needs to do to turn on the emulated graphics
>>> card and display output.
>> 
>> I'm seeing this error also. When I try to boot Mac OS 10.2 in
>> qemu-system-ppc, I just see a black window. When I switch from the
>> monitor to the vga window, then I see "Guest has not initialized the
>> display (yet)". It doesn't go away. OpenBIOS can't even be accessed
>> anymore. I think I started seeing this problem around the 18th of March.
>> I'm using Mac OS 10.6 as my host. 
> 
> I've just done some testing here and I see exactly the same issue -
> something is preventing OpenBIOS from executing. A quick session with
> git bisect points to the following:
> 
> 
> c3c1bb99d1c11978d9ce94d1bdcf0705378c1459 is the first bad commit
> commit c3c1bb99d1c11978d9ce94d1bdcf0705378c1459
> Author: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
> Date:   Mon Mar 16 22:35:54 2015 -0700
> 
>    exec: Respect as_tranlsate_internal length clamp
> 
>    address_space_translate_internal will clamp the *plen length argument
>    based on the size of the memory region being queried. The iommu walker
>    logic in addresss_space_translate was ignoring this by discarding the
>    post fn call value of *plen. Fix by just always using *plen as the
>    length argument throughout the fn, removing the len local variable.
> 
>    This fixes a bootloader bug when a single elf section spans multiple
>    QEMU memory regions.
> 
>    Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
>    Message-Id:
> <1426570554-15940-1-git-send-email-peter.crosthwaite@xilinx.com>
>    Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> 
> 
> Reproduction is easy with the command line given below:
> 
>  ./qemu-system-ppc -prom-env 'auto-boot?=false'
> 
> 
> ATB,
> 
> Mark.
> 


I reversed this patch on my local repo and that fixed the display issue for me. Given the fact it causes much worse problems than it said it solves, maybe this patch should be reversed. 

Re: [Qemu-devel] [Qemu-discuss] error - Guest has not initialized the display yet.

[Mark Cave-Ayland]

On 26/03/15 21:00, Paolo Bonzini wrote:

> On 26/03/2015 21:55, Peter Maydell wrote:
>> I feel like we're recapitulating history here -- is
>> c3c1bb99d undoing the fix that a87f39543a made for when we
>> tried this a year ago in 360e607, or is there something
>> more subtle going on ?
> 
> It's more subtle.  The patch should only make a difference when
> address_space_translate_internal modifies *plen.
> 
> The crux of the change is the first operand of this MIN:
> 
> -        len = MIN(len, (addr | iotlb.addr_mask) - addr + 1);
> +        *plen = MIN(*plen, (addr | iotlb.addr_mask) - addr + 1);
> 
> changing from len to *plen.

Ah so it's related to the VGA VBE register accesses again? Given that
this seems to be a bit of a corner case, is there any way of writing a
regression test to catch this?


ATB,

Mark.