unit_vm.c

#ifndef ACUTEST
#define ACUTEST
#include "acutest.h"
#endif

#include "paging.h"
#include "paging_add.h"

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <signal.h>

#define UNIT_VM
#include "unit.c"

void test_map_vm_small() {
	// Allocate 128 bytes of memory to serve as our store - only one frame!
	void *store = malloc(1<<7);

    // Initialise our mapping table
    void* table = pt_init();

	// Add some basic mappings to the table
	map_page_to_frame(table, 0, 0, false, false);
	map_page_to_frame(table, 1, 0, false, false);

    TEST_CHECK(!pt_error(table));

    // Try reading from page 0.
    char text[] = "Hello, world!";
    store_data(table, store, text, 0x0000, sizeof(text));

    // Then try reading from page 1. This should evict page 0 to disk.
    char buffer[128] = "";
    read_data(table, store, buffer, 0x0080, sizeof(buffer));

    // Then try re-reading from page 0. This should fault page 0 back into memory.
    read_data(table, store, buffer, 0x0000, sizeof(buffer));

    TEST_CHECK(strcmp(text, buffer) == 0);

    pt_free(table);
    free(store);
}

void test_demand_paging() {
	// Allocate 32 KiB of memory to serve as our store
	void *store = malloc(1<<15);

    // Initialise our mapping table
    void* table = pt_init();

	// Add some basic mappings to the table
	map_page_to_frame(table, 0, 4, true, false);
	map_page_to_frame(table, 1, 3, true, false);
	map_page_to_frame(table, 2, 0, true, false);
	map_page_to_frame(table, 3, 2, true, false);
	map_page_to_frame(table, 4, 1, true, false);

	char text[] = "It was the best of times, it was the worst of times, it was the age of wisdom, it was the age of foolishness, it was the epoch of belief, it was the epoch of incredulity, it was the season of light, it was the season of darkness, it was the spring of hope, it was the winter of despair, we had everything before us, we had nothing before us, we were all going direct to heaven, we were all going direct the other way–in short, the period was so far like the present period, that some of its noisiest authorities insisted on its being received, for good or for evil, in the superlative degree of comparison only.";
    
    // Write the text to the virtual memory disk file.
    // This should be page faulted from the disk when we first read the data.
    FILE* vm_file = fopen("./vm.bin", "wb");
    fwrite(text, 1, sizeof(text), vm_file);
    fclose(vm_file);

	char buffer[length(text)] = {0};
	read_data(table, store, buffer, 0, length(text));

    TEST_CHECK(strcmp(buffer, text) == 0);
    TEST_CHECK(!pt_error(table));

    pt_free(table);
    free(store);
}

// Clone of the test_fib function, but with all the pages mapped to the same frame so
// they need to be swapped out.
void test_fib_vm() {
	// Allocate 128 bytes of memory to serve as our store - only one frame!
	void *store = malloc(1<<7);

	// Initialise our mapping table
	void *table = pt_init();

	// Add some basic mappings to the table
	map_page_to_frame(table, 0, 0, false, false);
	map_page_to_frame(table, 1, 0, false, false);
	map_page_to_frame(table, 2, 0, false, false);
	map_page_to_frame(table, 3, 0, false, false);

    uint64_t init = 1;
    store_data(table, store, &init, 0, sizeof(uint64_t));
    store_data(table, store, &init, sizeof(uint64_t), sizeof(uint64_t));

    for(int i = 2; i < 64; i++) {
        uint64_t a = 0;
        read_data(table, store, &a, (i-2) * sizeof(uint64_t), sizeof(uint64_t));
        uint64_t b = 0;
        read_data(table, store, &b, (i-1) * sizeof(uint64_t), sizeof(uint64_t));
        uint64_t c = a + b;
        store_data(table, store, &c, i * sizeof(uint64_t), sizeof(uint64_t));
    }

    uint64_t data[64] = {0};
    read_data(table, store, &data, 0, 64 * sizeof(uint64_t));
    for (int i = 0; i < 64; i++) {
        printf("%lu, ", data[i]);
    }

    TEST_CHECK(!pt_error(table));

    pt_free(table);
    free(store);
}

// Clone of the test_cat function, but with all the pages mapped to the same frame so
// they need to be swapped out.
void test_cat_vm() {
	// Allocate 128 bytes of memory to serve as our store - only one frame!
	void *store = malloc(1<<7);

	// Initialise our mapping table
	void *table = pt_init();

	// Add some basic mappings to the table
	map_page_to_frame(table, 0, 0, false, false);
	map_page_to_frame(table, 1, 0, false, false);
	map_page_to_frame(table, 2, 0, false, false);
	map_page_to_frame(table, 3, 0, false, false);
	map_page_to_frame(table, 4, 0, false, false);
	map_page_to_frame(table, 5, 0, false, false);
	map_page_to_frame(table, 6, 0, false, false);
	map_page_to_frame(table, 7, 0, false, false);

	char text1[] = "It was the best of times, it was the worst of times, it was the age of wisdom, it was the age of foolishness, it was the epoch of belief, it was the epoch of incredulity, it was the season of light, it was the season of darkness, it was the spring of hope, it was the winter of despair, we had everything before us, we had nothing before us, ";
    char text2[] = "we were all going direct to heaven, we were all going direct the other way–in short, the period was so far like the present period, that some of its noisiest authorities insisted on its being received, for good or for evil, in the superlative degree of comparison only.";

    store_data(table, store, text1, 0x0000, length(text1));
    store_data(table, store, text2, 0x0200, length(text2));

    int error = page_cat(table, store, 0x0000, 0x0200);

    TEST_CHECK(!error);
    TEST_CHECK(!pt_error(table));

    char buffer[1024] = {0};
    read_data(table, store, buffer, 0x0000, 1024);
    
    char text[1024] = {0};
    strcpy(text, text1);
    strcat(text, text2);

    printf("\n%s\n", buffer);

    TEST_CHECK(strcmp(text, buffer) == 0);

    pt_free(table);
    free(store);
}

TEST_LIST = {
    {"init", test_init},
    {"map", test_map},
    {"translate", test_translate},
    {"translate_illegal", test_translate_illegal},
    {"unmap", test_unmap},
    {"alloc_small", test_alloc_small},
    {"alloc_larger", test_alloc_larger},
    {"store_illegal", test_store_illegal},
    {"read_illegal", test_read_illegal},
    {"fib", test_fib},
    {"cat", test_cat},
    {"write_protection", test_write_protection},
    {"map_vm_small", test_map_vm_small},
    {"demand_paging", test_demand_paging},
    {"fib_vm", test_fib_vm},
    {"cat_vm", test_cat_vm},
    {NULL, NULL}
};