Quelle  guest_memfd_test.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright Intel Corporation, 2023
 *
 * Author: Chao Peng <chao.p.peng@linux.intel.com>
 */
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <fcntl.h>

#include <linux/bitmap.h>
#include <linux/falloc.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>

#include "kvm_util.h"
#include "test_util.h"

static void test_file_read_write(int fd)
{
 char buf[64];

 TEST_ASSERT(read(fd, buf, sizeof(buf)) < 0,
      "read on a guest_mem fd should fail");
 TEST_ASSERT(write(fd, buf, sizeof(buf)) < 0,
      "write on a guest_mem fd should fail");
 TEST_ASSERT(pread(fd, buf, sizeof(buf), 0) < 0,
      "pread on a guest_mem fd should fail");
 TEST_ASSERT(pwrite(fd, buf, sizeof(buf), 0) < 0,
      "pwrite on a guest_mem fd should fail");
}

static void test_mmap(int fd, size_t page_size)
{
 char *mem;

 mem = mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
 TEST_ASSERT_EQ(mem, MAP_FAILED);
}

static void test_file_size(int fd, size_t page_size, size_t total_size)
{
 struct stat sb;
 int ret;

 ret = fstat(fd, &sb);
 TEST_ASSERT(!ret, "fstat should succeed");
 TEST_ASSERT_EQ(sb.st_size, total_size);
 TEST_ASSERT_EQ(sb.st_blksize, page_size);
}

static void test_fallocate(int fd, size_t page_size, size_t total_size)
{
 int ret;

 ret = fallocate(fd, FALLOC_FL_KEEP_SIZE, 0, total_size);
 TEST_ASSERT(!ret, "fallocate with aligned offset and size should succeed");

 ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE,
   page_size - 1, page_size);
 TEST_ASSERT(ret, "fallocate with unaligned offset should fail");

 ret = fallocate(fd, FALLOC_FL_KEEP_SIZE, total_size, page_size);
 TEST_ASSERT(ret, "fallocate beginning at total_size should fail");

 ret = fallocate(fd, FALLOC_FL_KEEP_SIZE, total_size + page_size, page_size);
 TEST_ASSERT(ret, "fallocate beginning after total_size should fail");

 ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE,
   total_size, page_size);
 TEST_ASSERT(!ret, "fallocate(PUNCH_HOLE) at total_size should succeed");

 ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE,
   total_size + page_size, page_size);
 TEST_ASSERT(!ret, "fallocate(PUNCH_HOLE) after total_size should succeed");

 ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE,
   page_size, page_size - 1);
 TEST_ASSERT(ret, "fallocate with unaligned size should fail");

 ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE,
   page_size, page_size);
 TEST_ASSERT(!ret, "fallocate(PUNCH_HOLE) with aligned offset and size should succeed");

 ret = fallocate(fd, FALLOC_FL_KEEP_SIZE, page_size, page_size);
 TEST_ASSERT(!ret, "fallocate to restore punched hole should succeed");
}

static void test_invalid_punch_hole(int fd, size_t page_size, size_t total_size)
{
 struct {
  off_t offset;
  off_t len;
 } testcases[] = {
  {0, 1},
  {0, page_size - 1},
  {0, page_size + 1},

  {1, 1},
  {1, page_size - 1},
  {1, page_size},
  {1, page_size + 1},

  {page_size, 1},
  {page_size, page_size - 1},
  {page_size, page_size + 1},
 };
 int ret, i;

 for (i = 0; i < ARRAY_SIZE(testcases); i++) {
  ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE,
    testcases[i].offset, testcases[i].len);
  TEST_ASSERT(ret == -1 && errno == EINVAL,
       "PUNCH_HOLE with !PAGE_SIZE offset (%lx) and/or length (%lx) should fail",
       testcases[i].offset, testcases[i].len);
 }
}

static void test_create_guest_memfd_invalid(struct kvm_vm *vm)
{
 size_t page_size = getpagesize();
 uint64_t flag;
 size_t size;
 int fd;

 for (size = 1; size < page_size; size++) {
  fd = __vm_create_guest_memfd(vm, size, 0);
  TEST_ASSERT(fd == -1 && errno == EINVAL,
       "guest_memfd() with non-page-aligned page size '0x%lx' should fail with EINVAL",
       size);
 }

 for (flag = BIT(0); flag; flag <<= 1) {
  fd = __vm_create_guest_memfd(vm, page_size, flag);
  TEST_ASSERT(fd == -1 && errno == EINVAL,
       "guest_memfd() with flag '0x%lx' should fail with EINVAL",
       flag);
 }
}

static void test_create_guest_memfd_multiple(struct kvm_vm *vm)
{
 int fd1, fd2, ret;
 struct stat st1, st2;

 fd1 = __vm_create_guest_memfd(vm, 4096, 0);
 TEST_ASSERT(fd1 != -1, "memfd creation should succeed");

 ret = fstat(fd1, &st1);
 TEST_ASSERT(ret != -1, "memfd fstat should succeed");
 TEST_ASSERT(st1.st_size == 4096, "memfd st_size should match requested size");

 fd2 = __vm_create_guest_memfd(vm, 8192, 0);
 TEST_ASSERT(fd2 != -1, "memfd creation should succeed");

 ret = fstat(fd2, &st2);
 TEST_ASSERT(ret != -1, "memfd fstat should succeed");
 TEST_ASSERT(st2.st_size == 8192, "second memfd st_size should match requested size");

 ret = fstat(fd1, &st1);
 TEST_ASSERT(ret != -1, "memfd fstat should succeed");
 TEST_ASSERT(st1.st_size == 4096, "first memfd st_size should still match requested size");
 TEST_ASSERT(st1.st_ino != st2.st_ino, "different memfd should have different inode numbers");

 close(fd2);
 close(fd1);
}

int main(int argc, char *argv[])
{
 size_t page_size;
 size_t total_size;
 int fd;
 struct kvm_vm *vm;

 TEST_REQUIRE(kvm_has_cap(KVM_CAP_GUEST_MEMFD));

 page_size = getpagesize();
 total_size = page_size * 4;

 vm = vm_create_barebones();

 test_create_guest_memfd_invalid(vm);
 test_create_guest_memfd_multiple(vm);

 fd = vm_create_guest_memfd(vm, total_size, 0);

 test_file_read_write(fd);
 test_mmap(fd, page_size);
 test_file_size(fd, page_size, total_size);
 test_fallocate(fd, page_size, total_size);
 test_invalid_punch_hole(fd, page_size, total_size);

 close(fd);
}