[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] [PATCH v3 5/6] vga: Use linear mapping + dirty logging

From: Avi Kivity
Subject: Re: [Qemu-devel] [PATCH v3 5/6] vga: Use linear mapping + dirty logging in chain 4 memory access mode
Date: Sun, 18 Sep 2011 14:28:24 +0300
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:6.0.2) Gecko/20110906 Thunderbird/6.0.2

On 09/18/2011 12:40 AM, Blue Swirl wrote:
On Thu, Sep 15, 2011 at 11:31 AM, Avi Kivity<address@hidden>  wrote:
>  On 09/15/2011 01:01 PM, Benjamin Herrenschmidt wrote:
>>  >    Sure :). So the problem is that when emulating the G3 Beige machine in
>>  >    QEMU (default ppc32 target) we also add a PCI VGA adapter. Apparently,
>>  >    on x86 that PCI VGA adapter can map the special VGA regions to
>>  >    somewhere, namely 0xa0000. With the memory api overhaul, this also
>>  >    slipped into the PPC world where mapping 0xa0000 with VGA adapters is
>>  >    a pretty bad idea, as it's occupied by RAM.
>>  >
>>  >    Now the discussion was on which level that mapping would happen and
>>  >    which devices go through which buses which then would filter certain
>>  >    ranges from being mapped. Basically, which way does a memory request
>>  >    from the CPU go on a G3 Beige machine until it arrives the VGA
>>  >    adapter?
>>  >
>>  >    I hope that concludes the actual question. Avi, if I explained this
>>  >    wrong, please correct me.
>>  Ok so there's several things here.
>>  First, the mapping from CPU addresses to PCI addresses. This depends on
>>  the host bridge chip. The MPC106, used in the Beige G3, itself supports
>>  different type of mappings.
>>    From memory, the way it's configured in a G3 is to have a 1:1 mapping of
>>  80000000 CPU to 80000000 PCI.
>>  That means that with this basic mapping, you cannot generate memory
>>  accesses to low PCI addresses such as 0xa0000.
>  Alex, what this means (I think is) that: pci_grackle_init() needs to create
>  a container memory region and pass it to pc_register_bus() as the pci
>  address space, and create and alias starting at 0x80000000 of the pci
>  address space, and map that alias at address 0x80000000 of the system
>  address space.
>  See pc_init1() creating pci_memory and passing it to i440fx_init(), which
>  then maps some aliases into the system address space and also gives it to
>  pci_bus_new().  It's essentially the same thing with different details.

I think the attached patch (on top of ppc-next) should do it, but it
doesn't. Only the top area of the screen is shown, the rest is black.

I can't see anything wrong with the patch either.

error compiling committee.c: too many arguments to function

reply via email to

[Prev in Thread] Current Thread [Next in Thread]