Of course, I forgot to attach the code.
On Tue, May 1, 2012 at 11:16 AM, Ribhi Kamal <[email protected]> wrote:
> 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
>
--
-- Ribhi
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/fdtable.h>
#include <linux/memory.h>
#include <linux/mm.h>
#include <asm-generic/io.h>
#ifndef PAGE_SIZE
#define PAGE_SIZE 4096
#endif
static char filePathBuf[PAGE_SIZE]; // This must be PAGE_SIZE
int init_module(void)
{
int idx = 0;
struct task_struct * task = NULL;
struct file * pFile = NULL;
char * filePath = NULL;
struct vm_area_struct * memArea = NULL;
for_each_process(task)
{
// The following is not needed
memArea = NULL;
pFile = NULL;
filePath = NULL;
task_lock(task);
//-1 unrunnable, 0 runnable, >0 stopped
if (task->state == -1)
printk("unrunnable " );
else if (task->state == 0)
printk("runnable " );
else if (task->state > 0)
printk("stopped " );
else
printk("unknown " );
printk("%s [%d]", task->comm, task->pid);
// Will not be used for vbox
if (task->files) {
printk(" - open file count %i",task->files->count.counter);
for ( idx = 0; idx < task->files->count.counter; idx++){
rcu_read_lock();
pFile = fcheck_files(task->files, idx);
if (pFile) {
filePathBuf[0] = '\0';
filePath = d_path(&pFile->f_path, (char *)filePathBuf , PAGE_SIZE );
if (filePath)
printk("\n\t'%s'", filePath);
}
rcu_read_unlock();
}
}
if (task->mm) {
printk("\nPrinting Memory Mapped Files\n");
for (idx=0;; idx++)
{
if (idx > 0)
// Move on to the next area
memArea = memArea->vm_next;
else
// Get the first area
memArea = task->mm->mmap;
if (memArea == NULL)
break;
// Here we care about any file-blacked area meaning that Text and
// Data are of interest and all pf memory mapping.
// So BSS, Heap and stack are ignored.
pFile = memArea->vm_file;
if (pFile == NULL)
continue;
rcu_read_lock();
filePathBuf[0] = '\0';
filePath = d_path(&pFile->f_path, (char *)filePathBuf , PAGE_SIZE );
rcu_read_unlock();
if (filePath) {
printk(" '%s'\n", filePath);
}
printk("\t vm_start:0x%lx vm_end:0x%lx\n",
memArea->vm_start,
memArea->vm_end);
printk("\t phy_start:0x%lx phy_end:0x%lx\n",
virt_to_phys((void *)memArea->vm_start),
virt_to_phys((void *)memArea->vm_end));
}
printk("Found %d memory areas\n", idx);
}
printk("\n\n");
task_unlock(task);
}
printk("\n");
return 0;
}
void cleanup_module(void)
{
printk(KERN_INFO "Cleaning Up.\n");
}
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