[ros-kernel] PCI device memory mapping into usermode - Page at address 0xXxx not usable

[James Tabor]

Hi,
Royce Mitchell III wrote:
> This question seems to have gone unanswered. Does anybody have any ideas 
> to share with Gregor?
> 
> Gregor Anich wrote:
> 
>> Hi!
>>
>> From time to time I am working to get the NVIDIA OpenGL driver running 
>> a bit... It is trying to map it's framebuffer into user-mode using 
>> VideoPortMapMemory() (reactos/drivers/video/videoprt/resource.c) which 
>> does not handle usermode at the moment, but I am trying to fix it. 
>> People told me to map a view of \Device\PhysicalMemory into usermode. 
>> If I do this (given the physical address from 
>> HalTranslateBusAddress()) all the calls succeed and I return a 
>> user-mode pointer. On the first access to this area a not-present 
>> fault happens and the mm is trying to create the mapping now. It fails 
>> in ntoskrnl/mm/i386/page.c, line 1212 (MmCreateVirtualMapping()) - 
>> Page at address 0xf0043000 not usable - bugcheck. This happens because 
>> the physical address is only checked against physical ram by 
>> MmIsUsablePage() I guess.
>> In windows 2k on my machine when I look at the memory ranges of my GF2 
>> GTS there is one which covers 0xf0000000-0xf7ffffff so I think 
>> 0xf0043000 should be usable and MmIsUsablePage() is wrong.
>>
>> When looking at MmIsUsablePage() (ntoskrnl/mm/freelist.c, line 746) I 
>> wonder why it doesn't check if the calculated Start is >= 
>> MmPageArraySize - isnt that a bug for any physical address checked >= 
>> MmPageArraySize * PAGE_SIZE?
>>
>> When I uncomment the call to MmIsUsablePage() and the following 
>> bugcheck the NVIDIA driver does neither crash nor display any kind of 
>> output.
>>
>> Thanks,
>>  blight
I'm having the same problem with map view. I can map a region to view and
try to access it through read virtual, I get a exception fault and sometimes
a page fault. We need to map I/O memory as Kernel mode user can read only or
map it to user mode r/w once the PCI device is id with memory I/O.

We need to implement memory boundary checking with the virtual kernel
functions.
James