Re: [Qemu-devel] [PATCH v2] memory: simple memory tree printer

[Avi Kivity <avi@redhat.com>]

On 09/18/2011 05:07 PM, Blue Swirl wrote:
> On Sun, Sep 18, 2011 at 1:53 PM, Avi Kivity<avi@redhat.com>  wrote:
> >  On 09/17/2011 10:27 PM, Blue Swirl wrote:
> >>
> >>  Add a monitor command 'info mtree' to show the memory hierarchy
> >>  much like /proc/iomem in Linux.
> >>
> >>
> >
> >  Still missing alias support.  PCI would be invisible on a PC (or any machine
> >  which has PCI holes implemented properly).
>
> Yes, that annoyed me too when debugging the PPC patch. But how should
> that look like? Consider for example that in the PPC case, range 0 to
> 0x80000000 is RAM from CPU point of view but only PCI MMIO space when
> looking after the PCI bridge. I/O shouldn't need separate handling if
> the CPU does not have PIO instructions, but instead PIO space is
> mapped as MMIO as on Sparc64 and PPC. I/O should be visible there.

Have some notation for a reference.  Example for PC:

Memory:
00000000-7fffffffffffffff system-memory container
   00000000-0009ffff alias @ram 00000000-0009ffff
   000a0000-000bffff alias @pci 000a0000-000bffff
   ...
   e0000000-ffffffff alias @pci e0000000-ffffffff

pci:
00000000-ffffffffff pci container
   000a0000-000bffff alias @vgam 00000000-0001ffff
   e0000000-e1ffffff alias @vram 00000000-01ffffff
   e2000000-e2001000 e1000-mmio

vram:
00000000-01ffffff vram ram

(each time you encounter a new alias target, add it to the print queue, 
it should work itself out naturally)

>
> >  Maybe we need to dump both the memory tree and the flat view - the memory
> >  tree for the logical hierarchy and the flat view to see what actually
> >  happens (I have an address, where does it go?)
>
> I have some trouble thinking about how to print fully converted,
> per-CPU memory trees. Also, if the memory API is fully embraced and
> extended to handle DMA and IOMMUs, each device could have a different
> view on the system memory. Perhaps the tool should take a device ID
> (also CPU ID) as a parameter to give it a starting point.

The possibilities are endless.

-- 
error compiling committee.c: too many arguments to function