Xen foreign memory mapping

xen_memmap.c

/*
 * gcc -o xen_memmap -lxenctrl xen_memmap.c
 */
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#define XC_WANT_COMPAT_MAP_FOREIGN_API 1
#include <xenctrl.h>

int main(int argc, char **argv) {

    xc_interface *xc = xc_interface_open(0, 0, 0);

    if (!xc) {
        fprintf(stderr, "xc_interface_open() failed!\n");
        return 0;
    }

    unsigned long pfn = strtoul(argv[1], NULL, 0);
    domid_t domainid = 1;

    void *memory = xc_map_foreign_range(xc, domainid, XC_PAGE_SIZE, PROT_READ, (unsigned long) pfn);

    if ( memory ) {
        /* Page is now mapped */

        munmap(memory, XC_PAGE_SIZE);
    }

    xc_interface_close(xc);

    return 0;
}