[vbox-dev] Page Fusion -- Validate my progress please.

[Ribhi Kamal]

Hi, I know that you are very busy but I would really appreciate it if
someone could find the time to make sure that I'm the right path.

As an exercise, I'm implementing Page Fusion for Linux guests. I setup my
dev environment (with UML) and wrote some code to pull the physical address
of each memory area for each process. There is still a lot of work to be
done before I merge my stuff to vboxguest, like the following:
1- Ignore the vboxguest module/service: The windows guest additions do
this, is it really needed?
2- Filter out pages that are NOT read or execute only.
3- Find out if the code is safe (locking wise)
4- ?

Questions:
(A) My most important question is what exactly I should be passing down to
the hypervisor? The physical address of the pages and their length,
correct? So in the case of "/lib/libc-2.11.3.so" below, I would
be registering four pages -- 0x37ff3000, 0x38131000, 0x38132000
and 0x38134000 -- each one has a PAGH_SIZE length.

(B) For scanning processes, is it safe to just add all the pages for files
under /lib /bin /usr and /sbin?

(C) Is my attached code accessing vm_area_struct safely?

Again, I appreciate any comments/help.

My test module populates the list of physical address an output like below.
 udevd [411]
  '/lib/libc-2.11.3.so' vm_mm:0x726ee9c  mmap_base:0x40000000
 vm_start:0x4003b000 vm_end:0x40179000
 phy_start:0x37ff3000 phy_end:0x38131000
  '/lib/libc-2.11.3.so' vm_mm:0x726ee9c  mmap_base:0x40000000
 vm_start:0x40179000 vm_end:0x4017a000
 phy_start:0x38131000 phy_end:0x38132000
  '/lib/libc-2.11.3.so' vm_mm:0x726ee9c  mmap_base:0x40000000
 vm_start:0x4017a000 vm_end:0x4017c000
 phy_start:0x38132000 phy_end:0x38134000
  '/lib/libc-2.11.3.so' vm_mm:0x726ee9c  mmap_base:0x40000000
 vm_start:0x4017c000 vm_end:0x4017d000
 phy_start:0x38134000 phy_end:0x38135000


udevd [412]
  '/lib/libc-2.11.3.so' vm_mm:0x726e2cc  mmap_base:0x40000000
 vm_start:0x4003b000 vm_end:0x40179000
 phy_start:0x37ff3000 phy_end:0x38131000
  '/lib/libc-2.11.3.so' vm_mm:0x726e2cc  mmap_base:0x40000000
 vm_start:0x40179000 vm_end:0x4017a000
 phy_start:0x38131000 phy_end:0x38132000
  '/lib/libc-2.11.3.so' vm_mm:0x726e2cc  mmap_base:0x40000000
 vm_start:0x4017a000 vm_end:0x4017c000
 phy_start:0x38132000 phy_end:0x38134000
  '/lib/libc-2.11.3.so' vm_mm:0x726e2cc  mmap_base:0x40000000
 vm_start:0x4017c000 vm_end:0x4017d000
 phy_start:0x38134000 phy_end:0x38135000


-- 
-- Ribhi
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