#!/usr/bin/env python3
# guest_pmap_win.py - dump present pages of a process's VA range through the
# guest's own pagemap (root in the guest). Batched reads (512 entries per
# pread) so a 256 MB window takes about a second, not minutes.
#
# Usage: sudo python3 guest_pmap_win.py <pid> <lo-hex> <hi-hex> [max-pairs] [pa-max-hex]
# Output: one "0x<va>,0x<pa>" line per present page (ascending VA), capped at
# max-pairs. PAs of 0 are skipped; pages above pa-max are skipped unless 0.
import os
import sys

pid = int(sys.argv[1])
lo = int(sys.argv[2], 16) & ~0xFFF
hi = int(sys.argv[3], 16)
maxp = int(sys.argv[4]) if len(sys.argv) > 4 else 20000
pa_max = int(sys.argv[5], 16) if len(sys.argv) > 5 else 0

BATCH = 512
out = []
fd = os.open('/proc/%d/pagemap' % pid, os.O_RDONLY)
try:
    va = lo
    while va < hi:
        n = min(BATCH, (hi - va) // 0x1000)
        if n <= 0:
            break
        os.lseek(fd, (va // 4096) * 8, 0)
        data = os.read(fd, n * 8)
        got = len(data) // 8
        for i in range(got):
            e = int.from_bytes(data[i * 8:i * 8 + 8], 'little')
            if not ((e >> 63) & 1):
                continue
            pfn = e & ((1 << 55) - 1)
            pa = pfn << 12
            if not pa:
                continue
            if pa_max and pa >= pa_max:
                continue
            out.append('0x%x,0x%x' % (va + i * 0x1000, pa))
            if len(out) >= maxp:
                print('\n'.join(out))
                sys.exit(0)
        va += got * 0x1000
finally:
    os.close(fd)
print('\n'.join(out))