mtrr_del_page
extern int mtrr_del_page(int reg, unsigned long base, unsigned long size);
err = mtrr_del_page(reg, 0, 0);
err = mtrr_del_page(-1, sentry.base, sentry.size);
reg = mtrr_del_page(-1, base, size);
return mtrr_del_page(reg, base >> PAGE_SHIFT, size >> PAGE_SHIFT);