pa

#include "fcntl.h"
#include "unistd.h"
#define PFN_MASK_SIZE  8
size_t virt2phy(size_t virtaddr)
{
    int fd, retval;
    size_t page, physaddr;
    size_t virt_pfn;
    size_t page_size;
    off_t offset;


    /* standard page size */
    page_size = 4096;

    fd = open("/proc/self/pagemap", O_RDONLY);
    if (fd < 0) {
        return -1;
    }

    virt_pfn = virtaddr / page_size;
    offset = sizeof(size_t) * virt_pfn;
    if (lseek(fd, offset, SEEK_SET) == (off_t) -1) {
        close(fd);
        return -2;
    }

    retval = read(fd, &page, sizeof(size_t));
    close(fd);
    if (retval < 0 || retval != sizeof(size_t)) {
        return -3;
    }

    /*
     * the pfn (page frame number) are bits 0-54 (see
     * pagemap.txt in linux Documentation)
     */
    physaddr = ((page & 0x7fffffffffffffULL) * page_size)
               + ((unsigned long)virtaddr % page_size);

    return physaddr;
}

#include "sys/mman.h"
int main(int argc, char *argv[])
{
    void *m1  = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0);
    void *m  = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0);

    uint64_t  r = va_to_pa((uint64_t)m);
    uint64_t r2 = virt2phy((uint64_t)m);
    return 0;
}