// SPDX-License-Identifier: GPL-2.0
/*
 * KVM dirty page logging test
 *
 * Copyright (C) 2018, Red Hat, Inc.
 */

#define _GNU_SOURCE /* for program_invocation_name */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <time.h>
#include <pthread.h>
#include <linux/bitmap.h>
#include <linux/bitops.h>

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

#define VCPU_ID                         1

/* The memory slot index to track dirty pages */
#define TEST_MEM_SLOT_INDEX             1

/* Default guest test virtual memory offset */
#define DEFAULT_GUEST_TEST_MEM          0xc0000000

/* How many pages to dirty for each guest loop */
#define TEST_PAGES_PER_LOOP             1024

/* How many host loops to run (one KVM_GET_DIRTY_LOG for each loop) */
#define TEST_HOST_LOOP_N                32UL

/* Interval for each host loop (ms) */
#define TEST_HOST_LOOP_INTERVAL         10UL

/* Dirty bitmaps are always little endian, so we need to swap on big endian */
#if defined(__s390x__)
# define BITOP_LE_SWIZZLE       ((BITS_PER_LONG-1) & ~0x7)
# define test_bit_le(nr, addr) \
        test_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
# define set_bit_le(nr, addr) \
        set_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
# define clear_bit_le(nr, addr) \
        clear_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
# define test_and_set_bit_le(nr, addr) \
        test_and_set_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
# define test_and_clear_bit_le(nr, addr) \
        test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, addr)
#else
# define test_bit_le            test_bit
# define set_bit_le             set_bit
# define clear_bit_le           clear_bit
# define test_and_set_bit_le    test_and_set_bit
# define test_and_clear_bit_le  test_and_clear_bit
#endif

/*
 * Guest/Host shared variables. Ensure addr_gva2hva() and/or
 * sync_global_to/from_guest() are used when accessing from
 * the host. READ/WRITE_ONCE() should also be used with anything
 * that may change.
 */
static uint64_t host_page_size;
static uint64_t guest_page_size;
static uint64_t guest_num_pages;
static uint64_t random_array[TEST_PAGES_PER_LOOP];
static uint64_t iteration;

/*
 * Guest physical memory offset of the testing memory slot.
 * This will be set to the topmost valid physical address minus
 * the test memory size.
 */
static uint64_t guest_test_phys_mem;

/*
 * Guest virtual memory offset of the testing memory slot.
 * Must not conflict with identity mapped test code.
 */
static uint64_t guest_test_virt_mem = DEFAULT_GUEST_TEST_MEM;

/*
 * Continuously write to the first 8 bytes of a random pages within
 * the testing memory region.
 */
static void guest_code(void)
{
        uint64_t addr;
        int i;

        /*
         * On s390x, all pages of a 1M segment are initially marked as dirty
         * when a page of the segment is written to for the very first time.
         * To compensate this specialty in this test, we need to touch all
         * pages during the first iteration.
         */
        for (i = 0; i < guest_num_pages; i++) {
                addr = guest_test_virt_mem + i * guest_page_size;
                *(uint64_t *)addr = READ_ONCE(iteration);
        }

        while (true) {
                for (i = 0; i < TEST_PAGES_PER_LOOP; i++) {
                        addr = guest_test_virt_mem;
                        addr += (READ_ONCE(random_array[i]) % guest_num_pages)
                                * guest_page_size;
                        addr &= ~(host_page_size - 1);
                        *(uint64_t *)addr = READ_ONCE(iteration);
                }

                /* Tell the host that we need more random numbers */
                GUEST_SYNC(1);
        }
}

/* Host variables */
static bool host_quit;

/* Points to the test VM memory region on which we track dirty logs */
static void *host_test_mem;
static uint64_t host_num_pages;

/* For statistics only */
static uint64_t host_dirty_count;
static uint64_t host_clear_count;
static uint64_t host_track_next_count;

/*
 * We use this bitmap to track some pages that should have its dirty
 * bit set in the _next_ iteration.  For example, if we detected the
 * page value changed to current iteration but at the same time the
 * page bit is cleared in the latest bitmap, then the system must
 * report that write in the next get dirty log call.
 */
static unsigned long *host_bmap_track;

static void generate_random_array(uint64_t *guest_array, uint64_t size)
{
        uint64_t i;

        for (i = 0; i < size; i++)
                guest_array[i] = random();
}

static void *vcpu_worker(void *data)
{
        int ret;
        struct kvm_vm *vm = data;
        uint64_t *guest_array;
        uint64_t pages_count = 0;
        struct kvm_run *run;

        run = vcpu_state(vm, VCPU_ID);

        guest_array = addr_gva2hva(vm, (vm_vaddr_t)random_array);
        generate_random_array(guest_array, TEST_PAGES_PER_LOOP);

        while (!READ_ONCE(host_quit)) {
                /* Let the guest dirty the random pages */
                ret = _vcpu_run(vm, VCPU_ID);
                TEST_ASSERT(ret == 0, "vcpu_run failed: %d\n", ret);
                if (get_ucall(vm, VCPU_ID, NULL) == UCALL_SYNC) {
                        pages_count += TEST_PAGES_PER_LOOP;
                        generate_random_array(guest_array, TEST_PAGES_PER_LOOP);
                } else {
                        TEST_ASSERT(false,
                                    "Invalid guest sync status: "
                                    "exit_reason=%s\n",
                                    exit_reason_str(run->exit_reason));
                }
        }

        DEBUG("Dirtied %"PRIu64" pages\n", pages_count);

        return NULL;
}

static void vm_dirty_log_verify(unsigned long *bmap)
{
        uint64_t page;
        uint64_t *value_ptr;
        uint64_t step = host_page_size >= guest_page_size ? 1 :
                                guest_page_size / host_page_size;

        for (page = 0; page < host_num_pages; page += step) {
                value_ptr = host_test_mem + page * host_page_size;

                /* If this is a special page that we were tracking... */
                if (test_and_clear_bit_le(page, host_bmap_track)) {
                        host_track_next_count++;
                        TEST_ASSERT(test_bit_le(page, bmap),
                                    "Page %"PRIu64" should have its dirty bit "
                                    "set in this iteration but it is missing",
                                    page);
                }

                if (test_bit_le(page, bmap)) {
                        host_dirty_count++;
                        /*
                         * If the bit is set, the value written onto
                         * the corresponding page should be either the
                         * previous iteration number or the current one.
                         */
                        TEST_ASSERT(*value_ptr == iteration ||
                                    *value_ptr == iteration - 1,
                                    "Set page %"PRIu64" value %"PRIu64
                                    " incorrect (iteration=%"PRIu64")",
                                    page, *value_ptr, iteration);
                } else {
                        host_clear_count++;
                        /*
                         * If cleared, the value written can be any
                         * value smaller or equals to the iteration
                         * number.  Note that the value can be exactly
                         * (iteration-1) if that write can happen
                         * like this:
                         *
                         * (1) increase loop count to "iteration-1"
                         * (2) write to page P happens (with value
                         *     "iteration-1")
                         * (3) get dirty log for "iteration-1"; we'll
                         *     see that page P bit is set (dirtied),
                         *     and not set the bit in host_bmap_track
                         * (4) increase loop count to "iteration"
                         *     (which is current iteration)
                         * (5) get dirty log for current iteration,
                         *     we'll see that page P is cleared, with
                         *     value "iteration-1".
                         */
                        TEST_ASSERT(*value_ptr <= iteration,
                                    "Clear page %"PRIu64" value %"PRIu64
                                    " incorrect (iteration=%"PRIu64")",
                                    page, *value_ptr, iteration);
                        if (*value_ptr == iteration) {
                                /*
                                 * This page is _just_ modified; it
                                 * should report its dirtyness in the
                                 * next run
                                 */
                                set_bit_le(page, host_bmap_track);
                        }
                }
        }
}

static struct kvm_vm *create_vm(enum vm_guest_mode mode, uint32_t vcpuid,
                                uint64_t extra_mem_pages, void *guest_code)
{
        struct kvm_vm *vm;
        uint64_t extra_pg_pages = extra_mem_pages / 512 * 2;

        vm = _vm_create(mode, DEFAULT_GUEST_PHY_PAGES + extra_pg_pages, O_RDWR);
        kvm_vm_elf_load(vm, program_invocation_name, 0, 0);
#ifdef __x86_64__
        vm_create_irqchip(vm);
#endif
        vm_vcpu_add_default(vm, vcpuid, guest_code);
        return vm;
}

#define DIRTY_MEM_BITS 30 /* 1G */
#define PAGE_SHIFT_4K  12

static void run_test(enum vm_guest_mode mode, unsigned long iterations,
                     unsigned long interval, uint64_t phys_offset)
{
        pthread_t vcpu_thread;
        struct kvm_vm *vm;
        unsigned long *bmap;

        /*
         * We reserve page table for 2 times of extra dirty mem which
         * will definitely cover the original (1G+) test range.  Here
         * we do the calculation with 4K page size which is the
         * smallest so the page number will be enough for all archs
         * (e.g., 64K page size guest will need even less memory for
         * page tables).
         */
        vm = create_vm(mode, VCPU_ID,
                       2ul << (DIRTY_MEM_BITS - PAGE_SHIFT_4K),
                       guest_code);

        guest_page_size = vm_get_page_size(vm);
        /*
         * A little more than 1G of guest page sized pages.  Cover the
         * case where the size is not aligned to 64 pages.
         */
        guest_num_pages = (1ul << (DIRTY_MEM_BITS -
                                   vm_get_page_shift(vm))) + 16;
#ifdef __s390x__
        /* Round up to multiple of 1M (segment size) */
        guest_num_pages = (guest_num_pages + 0xff) & ~0xffUL;
#endif
        host_page_size = getpagesize();
        host_num_pages = (guest_num_pages * guest_page_size) / host_page_size +
                         !!((guest_num_pages * guest_page_size) % host_page_size);

        if (!phys_offset) {
                guest_test_phys_mem = (vm_get_max_gfn(vm) -
                                       guest_num_pages) * guest_page_size;
                guest_test_phys_mem &= ~(host_page_size - 1);
        } else {
                guest_test_phys_mem = phys_offset;
        }

#ifdef __s390x__
        /* Align to 1M (segment size) */
        guest_test_phys_mem &= ~((1 << 20) - 1);
#endif

        DEBUG("guest physical test memory offset: 0x%lx\n", guest_test_phys_mem);

        bmap = bitmap_alloc(host_num_pages);
        host_bmap_track = bitmap_alloc(host_num_pages);

#ifdef USE_CLEAR_DIRTY_LOG
        struct kvm_enable_cap cap = {};

        cap.cap = KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2;
        cap.args[0] = 1;
        vm_enable_cap(vm, &cap);
#endif

        /* Add an extra memory slot for testing dirty logging */
        vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
                                    guest_test_phys_mem,
                                    TEST_MEM_SLOT_INDEX,
                                    guest_num_pages,
                                    KVM_MEM_LOG_DIRTY_PAGES);

        /* Do mapping for the dirty track memory slot */
        virt_map(vm, guest_test_virt_mem, guest_test_phys_mem,
                 guest_num_pages * guest_page_size, 0);

        /* Cache the HVA pointer of the region */
        host_test_mem = addr_gpa2hva(vm, (vm_paddr_t)guest_test_phys_mem);

#ifdef __x86_64__
        vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
#endif
#ifdef __aarch64__
        ucall_init(vm, NULL);
#endif

        /* Export the shared variables to the guest */
        sync_global_to_guest(vm, host_page_size);
        sync_global_to_guest(vm, guest_page_size);
        sync_global_to_guest(vm, guest_test_virt_mem);
        sync_global_to_guest(vm, guest_num_pages);

        /* Start the iterations */
        iteration = 1;
        sync_global_to_guest(vm, iteration);
        host_quit = false;
        host_dirty_count = 0;
        host_clear_count = 0;
        host_track_next_count = 0;

        pthread_create(&vcpu_thread, NULL, vcpu_worker, vm);

        while (iteration < iterations) {
                /* Give the vcpu thread some time to dirty some pages */
                usleep(interval * 1000);
                kvm_vm_get_dirty_log(vm, TEST_MEM_SLOT_INDEX, bmap);
#ifdef USE_CLEAR_DIRTY_LOG
                kvm_vm_clear_dirty_log(vm, TEST_MEM_SLOT_INDEX, bmap, 0,
                                       host_num_pages);
#endif
                vm_dirty_log_verify(bmap);
                iteration++;
                sync_global_to_guest(vm, iteration);
        }

        /* Tell the vcpu thread to quit */
        host_quit = true;
        pthread_join(vcpu_thread, NULL);

        DEBUG("Total bits checked: dirty (%"PRIu64"), clear (%"PRIu64"), "
              "track_next (%"PRIu64")\n", host_dirty_count, host_clear_count,
              host_track_next_count);

        free(bmap);
        free(host_bmap_track);
        ucall_uninit(vm);
        kvm_vm_free(vm);
}

struct vm_guest_mode_params {
        bool supported;
        bool enabled;
};
struct vm_guest_mode_params vm_guest_mode_params[NUM_VM_MODES];

#define vm_guest_mode_params_init(mode, supported, enabled)                                     \
({                                                                                              \
        vm_guest_mode_params[mode] = (struct vm_guest_mode_params){ supported, enabled };       \
})

static void help(char *name)
{
        int i;

        puts("");
        printf("usage: %s [-h] [-i iterations] [-I interval] "
               "[-p offset] [-m mode]\n", name);
        puts("");
        printf(" -i: specify iteration counts (default: %"PRIu64")\n",
               TEST_HOST_LOOP_N);
        printf(" -I: specify interval in ms (default: %"PRIu64" ms)\n",
               TEST_HOST_LOOP_INTERVAL);
        printf(" -p: specify guest physical test memory offset\n"
               "     Warning: a low offset can conflict with the loaded test code.\n");
        printf(" -m: specify the guest mode ID to test "
               "(default: test all supported modes)\n"
               "     This option may be used multiple times.\n"
               "     Guest mode IDs:\n");
        for (i = 0; i < NUM_VM_MODES; ++i) {
                printf("         %d:    %s%s\n", i, vm_guest_mode_string(i),
                       vm_guest_mode_params[i].supported ? " (supported)" : "");
        }
        puts("");
        exit(0);
}

int main(int argc, char *argv[])
{
        unsigned long iterations = TEST_HOST_LOOP_N;
        unsigned long interval = TEST_HOST_LOOP_INTERVAL;
        bool mode_selected = false;
        uint64_t phys_offset = 0;
        unsigned int mode;
        int opt, i;
#ifdef __aarch64__
        unsigned int host_ipa_limit;
#endif

#ifdef USE_CLEAR_DIRTY_LOG
        if (!kvm_check_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2)) {
                fprintf(stderr, "KVM_CLEAR_DIRTY_LOG not available, skipping tests\n");
                exit(KSFT_SKIP);
        }
#endif

#ifdef __x86_64__
        vm_guest_mode_params_init(VM_MODE_PXXV48_4K, true, true);
#endif
#ifdef __aarch64__
        vm_guest_mode_params_init(VM_MODE_P40V48_4K, true, true);
        vm_guest_mode_params_init(VM_MODE_P40V48_64K, true, true);

        host_ipa_limit = kvm_check_cap(KVM_CAP_ARM_VM_IPA_SIZE);
        if (host_ipa_limit >= 52)
                vm_guest_mode_params_init(VM_MODE_P52V48_64K, true, true);
        if (host_ipa_limit >= 48) {
                vm_guest_mode_params_init(VM_MODE_P48V48_4K, true, true);
                vm_guest_mode_params_init(VM_MODE_P48V48_64K, true, true);
        }
#endif
#ifdef __s390x__
        vm_guest_mode_params_init(VM_MODE_P40V48_4K, true, true);
#endif

        while ((opt = getopt(argc, argv, "hi:I:p:m:")) != -1) {
                switch (opt) {
                case 'i':
                        iterations = strtol(optarg, NULL, 10);
                        break;
                case 'I':
                        interval = strtol(optarg, NULL, 10);
                        break;
                case 'p':
                        phys_offset = strtoull(optarg, NULL, 0);
                        break;
                case 'm':
                        if (!mode_selected) {
                                for (i = 0; i < NUM_VM_MODES; ++i)
                                        vm_guest_mode_params[i].enabled = false;
                                mode_selected = true;
                        }
                        mode = strtoul(optarg, NULL, 10);
                        TEST_ASSERT(mode < NUM_VM_MODES,
                                    "Guest mode ID %d too big", mode);
                        vm_guest_mode_params[mode].enabled = true;
                        break;
                case 'h':
                default:
                        help(argv[0]);
                        break;
                }
        }

        TEST_ASSERT(iterations > 2, "Iterations must be greater than two");
        TEST_ASSERT(interval > 0, "Interval must be greater than zero");

        DEBUG("Test iterations: %"PRIu64", interval: %"PRIu64" (ms)\n",
              iterations, interval);

        srandom(time(0));

        for (i = 0; i < NUM_VM_MODES; ++i) {
                if (!vm_guest_mode_params[i].enabled)
                        continue;
                TEST_ASSERT(vm_guest_mode_params[i].supported,
                            "Guest mode ID %d (%s) not supported.",
                            i, vm_guest_mode_string(i));
                run_test(i, iterations, interval, phys_offset);
        }

        return 0;
}