// SPDX-License-Identifier: GPL-2.0
/*
 * KVM demand paging test
 * Adapted from dirty_log_test.c
 *
 * Copyright (C) 2018, Red Hat, Inc.
 * Copyright (C) 2019, Google, Inc.
 */

#define _GNU_SOURCE /* for program_invocation_name */

#include <stdio.h>
#include <stdlib.h>
#include <sys/syscall.h>
#include <unistd.h>
#include <asm/unistd.h>
#include <time.h>
#include <poll.h>
#include <pthread.h>
#include <linux/bitmap.h>
#include <linux/bitops.h>
#include <linux/userfaultfd.h>

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

#ifdef __NR_userfaultfd

/* The memory slot index demand page */
#define TEST_MEM_SLOT_INDEX             1

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

#define DEFAULT_GUEST_TEST_MEM_SIZE (1 << 30) /* 1G */

#ifdef PRINT_PER_PAGE_UPDATES
#define PER_PAGE_DEBUG(...) printf(__VA_ARGS__)
#else
#define PER_PAGE_DEBUG(...) _no_printf(__VA_ARGS__)
#endif

#ifdef PRINT_PER_VCPU_UPDATES
#define PER_VCPU_DEBUG(...) printf(__VA_ARGS__)
#else
#define PER_VCPU_DEBUG(...) _no_printf(__VA_ARGS__)
#endif

#define MAX_VCPUS 512

/*
 * 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 char *guest_data_prototype;

/*
 * 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;

struct vcpu_args {
        uint64_t gva;
        uint64_t pages;

        /* Only used by the host userspace part of the vCPU thread */
        int vcpu_id;
        struct kvm_vm *vm;
};

static struct vcpu_args vcpu_args[MAX_VCPUS];

/*
 * Continuously write to the first 8 bytes of each page in the demand paging
 * memory region.
 */
static void guest_code(uint32_t vcpu_id)
{
        uint64_t gva;
        uint64_t pages;
        int i;

        /* Make sure vCPU args data structure is not corrupt. */
        GUEST_ASSERT(vcpu_args[vcpu_id].vcpu_id == vcpu_id);

        gva = vcpu_args[vcpu_id].gva;
        pages = vcpu_args[vcpu_id].pages;

        for (i = 0; i < pages; i++) {
                uint64_t addr = gva + (i * guest_page_size);

                addr &= ~(host_page_size - 1);
                *(uint64_t *)addr = 0x0123456789ABCDEF;
        }

        GUEST_SYNC(1);
}

static void *vcpu_worker(void *data)
{
        int ret;
        struct vcpu_args *args = (struct vcpu_args *)data;
        struct kvm_vm *vm = args->vm;
        int vcpu_id = args->vcpu_id;
        struct kvm_run *run;
        struct timespec start, end, ts_diff;

        vcpu_args_set(vm, vcpu_id, 1, vcpu_id);
        run = vcpu_state(vm, vcpu_id);

        clock_gettime(CLOCK_MONOTONIC, &start);

        /* Let the guest access its memory */
        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) {
                TEST_ASSERT(false,
                            "Invalid guest sync status: exit_reason=%s\n",
                            exit_reason_str(run->exit_reason));
        }

        clock_gettime(CLOCK_MONOTONIC, &end);
        ts_diff = timespec_sub(end, start);
        PER_VCPU_DEBUG("vCPU %d execution time: %ld.%.9lds\n", vcpu_id,
                       ts_diff.tv_sec, ts_diff.tv_nsec);

        return NULL;
}

#define PAGE_SHIFT_4K  12
#define PTES_PER_4K_PT 512

static struct kvm_vm *create_vm(enum vm_guest_mode mode, int vcpus,
                                uint64_t vcpu_memory_bytes)
{
        struct kvm_vm *vm;
        uint64_t pages = DEFAULT_GUEST_PHY_PAGES;

        /* Account for a few pages per-vCPU for stacks */
        pages += DEFAULT_STACK_PGS * vcpus;

        /*
         * Reserve twice the ammount of memory needed to map the test region and
         * the page table / stacks region, at 4k, for page tables. Do the
         * calculation with 4K page size: the smallest of all archs. (e.g., 64K
         * page size guest will need even less memory for page tables).
         */
        pages += (2 * pages) / PTES_PER_4K_PT;
        pages += ((2 * vcpus * vcpu_memory_bytes) >> PAGE_SHIFT_4K) /
                 PTES_PER_4K_PT;
        pages = vm_adjust_num_guest_pages(mode, pages);

        pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode));

        vm = _vm_create(mode, pages, O_RDWR);
        kvm_vm_elf_load(vm, program_invocation_name, 0, 0);
#ifdef __x86_64__
        vm_create_irqchip(vm);
#endif
        return vm;
}

static int handle_uffd_page_request(int uffd, uint64_t addr)
{
        pid_t tid;
        struct timespec start;
        struct timespec end;
        struct uffdio_copy copy;
        int r;

        tid = syscall(__NR_gettid);

        copy.src = (uint64_t)guest_data_prototype;
        copy.dst = addr;
        copy.len = host_page_size;
        copy.mode = 0;

        clock_gettime(CLOCK_MONOTONIC, &start);

        r = ioctl(uffd, UFFDIO_COPY, &copy);
        if (r == -1) {
                pr_info("Failed Paged in 0x%lx from thread %d with errno: %d\n",
                        addr, tid, errno);
                return r;
        }

        clock_gettime(CLOCK_MONOTONIC, &end);

        PER_PAGE_DEBUG("UFFDIO_COPY %d \t%ld ns\n", tid,
                       timespec_to_ns(timespec_sub(end, start)));
        PER_PAGE_DEBUG("Paged in %ld bytes at 0x%lx from thread %d\n",
                       host_page_size, addr, tid);

        return 0;
}

bool quit_uffd_thread;

struct uffd_handler_args {
        int uffd;
        int pipefd;
        useconds_t delay;
};

static void *uffd_handler_thread_fn(void *arg)
{
        struct uffd_handler_args *uffd_args = (struct uffd_handler_args *)arg;
        int uffd = uffd_args->uffd;
        int pipefd = uffd_args->pipefd;
        useconds_t delay = uffd_args->delay;
        int64_t pages = 0;
        struct timespec start, end, ts_diff;

        clock_gettime(CLOCK_MONOTONIC, &start);
        while (!quit_uffd_thread) {
                struct uffd_msg msg;
                struct pollfd pollfd[2];
                char tmp_chr;
                int r;
                uint64_t addr;

                pollfd[0].fd = uffd;
                pollfd[0].events = POLLIN;
                pollfd[1].fd = pipefd;
                pollfd[1].events = POLLIN;

                r = poll(pollfd, 2, -1);
                switch (r) {
                case -1:
                        pr_info("poll err");
                        continue;
                case 0:
                        continue;
                case 1:
                        break;
                default:
                        pr_info("Polling uffd returned %d", r);
                        return NULL;
                }

                if (pollfd[0].revents & POLLERR) {
                        pr_info("uffd revents has POLLERR");
                        return NULL;
                }

                if (pollfd[1].revents & POLLIN) {
                        r = read(pollfd[1].fd, &tmp_chr, 1);
                        TEST_ASSERT(r == 1,
                                    "Error reading pipefd in UFFD thread\n");
                        return NULL;
                }

                if (!pollfd[0].revents & POLLIN)
                        continue;

                r = read(uffd, &msg, sizeof(msg));
                if (r == -1) {
                        if (errno == EAGAIN)
                                continue;
                        pr_info("Read of uffd gor errno %d", errno);
                        return NULL;
                }

                if (r != sizeof(msg)) {
                        pr_info("Read on uffd returned unexpected size: %d bytes", r);
                        return NULL;
                }

                if (!(msg.event & UFFD_EVENT_PAGEFAULT))
                        continue;

                if (delay)
                        usleep(delay);
                addr =  msg.arg.pagefault.address;
                r = handle_uffd_page_request(uffd, addr);
                if (r < 0)
                        return NULL;
                pages++;
        }

        clock_gettime(CLOCK_MONOTONIC, &end);
        ts_diff = timespec_sub(end, start);
        PER_VCPU_DEBUG("userfaulted %ld pages over %ld.%.9lds. (%f/sec)\n",
                       pages, ts_diff.tv_sec, ts_diff.tv_nsec,
                       pages / ((double)ts_diff.tv_sec + (double)ts_diff.tv_nsec / 100000000.0));

        return NULL;
}

static int setup_demand_paging(struct kvm_vm *vm,
                               pthread_t *uffd_handler_thread, int pipefd,
                               useconds_t uffd_delay,
                               struct uffd_handler_args *uffd_args,
                               void *hva, uint64_t len)
{
        int uffd;
        struct uffdio_api uffdio_api;
        struct uffdio_register uffdio_register;

        uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
        if (uffd == -1) {
                pr_info("uffd creation failed\n");
                return -1;
        }

        uffdio_api.api = UFFD_API;
        uffdio_api.features = 0;
        if (ioctl(uffd, UFFDIO_API, &uffdio_api) == -1) {
                pr_info("ioctl uffdio_api failed\n");
                return -1;
        }

        uffdio_register.range.start = (uint64_t)hva;
        uffdio_register.range.len = len;
        uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
        if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register) == -1) {
                pr_info("ioctl uffdio_register failed\n");
                return -1;
        }

        if ((uffdio_register.ioctls & UFFD_API_RANGE_IOCTLS) !=
                        UFFD_API_RANGE_IOCTLS) {
                pr_info("unexpected userfaultfd ioctl set\n");
                return -1;
        }

        uffd_args->uffd = uffd;
        uffd_args->pipefd = pipefd;
        uffd_args->delay = uffd_delay;
        pthread_create(uffd_handler_thread, NULL, uffd_handler_thread_fn,
                       uffd_args);

        PER_VCPU_DEBUG("Created uffd thread for HVA range [%p, %p)\n",
                       hva, hva + len);

        return 0;
}

static void run_test(enum vm_guest_mode mode, bool use_uffd,
                     useconds_t uffd_delay, int vcpus,
                     uint64_t vcpu_memory_bytes)
{
        pthread_t *vcpu_threads;
        pthread_t *uffd_handler_threads = NULL;
        struct uffd_handler_args *uffd_args = NULL;
        struct timespec start, end, ts_diff;
        int *pipefds = NULL;
        struct kvm_vm *vm;
        uint64_t guest_num_pages;
        int vcpu_id;
        int r;

        vm = create_vm(mode, vcpus, vcpu_memory_bytes);

        guest_page_size = vm_get_page_size(vm);

        TEST_ASSERT(vcpu_memory_bytes % guest_page_size == 0,
                    "Guest memory size is not guest page size aligned.");

        guest_num_pages = (vcpus * vcpu_memory_bytes) / guest_page_size;
        guest_num_pages = vm_adjust_num_guest_pages(mode, guest_num_pages);

        /*
         * If there should be more memory in the guest test region than there
         * can be pages in the guest, it will definitely cause problems.
         */
        TEST_ASSERT(guest_num_pages < vm_get_max_gfn(vm),
                    "Requested more guest memory than address space allows.\n"
                    "    guest pages: %lx max gfn: %x vcpus: %d wss: %lx]\n",
                    guest_num_pages, vm_get_max_gfn(vm), vcpus,
                    vcpu_memory_bytes);

        host_page_size = getpagesize();
        TEST_ASSERT(vcpu_memory_bytes % host_page_size == 0,
                    "Guest memory size is not host page size aligned.");

        guest_test_phys_mem = (vm_get_max_gfn(vm) - guest_num_pages) *
                              guest_page_size;
        guest_test_phys_mem &= ~(host_page_size - 1);

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

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

        /* Add an extra memory slot for testing demand paging */
        vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
                                    guest_test_phys_mem,
                                    TEST_MEM_SLOT_INDEX,
                                    guest_num_pages, 0);

        /* Do mapping for the demand paging memory slot */
        virt_map(vm, guest_test_virt_mem, guest_test_phys_mem, guest_num_pages, 0);

        ucall_init(vm, NULL);

        guest_data_prototype = malloc(host_page_size);
        TEST_ASSERT(guest_data_prototype,
                    "Failed to allocate buffer for guest data pattern");
        memset(guest_data_prototype, 0xAB, host_page_size);

        vcpu_threads = malloc(vcpus * sizeof(*vcpu_threads));
        TEST_ASSERT(vcpu_threads, "Memory allocation failed");

        if (use_uffd) {
                uffd_handler_threads =
                        malloc(vcpus * sizeof(*uffd_handler_threads));
                TEST_ASSERT(uffd_handler_threads, "Memory allocation failed");

                uffd_args = malloc(vcpus * sizeof(*uffd_args));
                TEST_ASSERT(uffd_args, "Memory allocation failed");

                pipefds = malloc(sizeof(int) * vcpus * 2);
                TEST_ASSERT(pipefds, "Unable to allocate memory for pipefd");
        }

        for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {
                vm_paddr_t vcpu_gpa;
                void *vcpu_hva;

                vm_vcpu_add_default(vm, vcpu_id, guest_code);

                vcpu_gpa = guest_test_phys_mem + (vcpu_id * vcpu_memory_bytes);
                PER_VCPU_DEBUG("Added VCPU %d with test mem gpa [%lx, %lx)\n",
                               vcpu_id, vcpu_gpa, vcpu_gpa + vcpu_memory_bytes);

                /* Cache the HVA pointer of the region */
                vcpu_hva = addr_gpa2hva(vm, vcpu_gpa);

                if (use_uffd) {
                        /*
                         * Set up user fault fd to handle demand paging
                         * requests.
                         */
                        r = pipe2(&pipefds[vcpu_id * 2],
                                  O_CLOEXEC | O_NONBLOCK);
                        TEST_ASSERT(!r, "Failed to set up pipefd");

                        r = setup_demand_paging(vm,
                                                &uffd_handler_threads[vcpu_id],
                                                pipefds[vcpu_id * 2],
                                                uffd_delay, &uffd_args[vcpu_id],
                                                vcpu_hva, vcpu_memory_bytes);
                        if (r < 0)
                                exit(-r);
                }

#ifdef __x86_64__
                vcpu_set_cpuid(vm, vcpu_id, kvm_get_supported_cpuid());
#endif

                vcpu_args[vcpu_id].vm = vm;
                vcpu_args[vcpu_id].vcpu_id = vcpu_id;
                vcpu_args[vcpu_id].gva = guest_test_virt_mem +
                                         (vcpu_id * vcpu_memory_bytes);
                vcpu_args[vcpu_id].pages = vcpu_memory_bytes / guest_page_size;
        }

        /* 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, vcpu_args);

        pr_info("Finished creating vCPUs and starting uffd threads\n");

        clock_gettime(CLOCK_MONOTONIC, &start);

        for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {
                pthread_create(&vcpu_threads[vcpu_id], NULL, vcpu_worker,
                               &vcpu_args[vcpu_id]);
        }

        pr_info("Started all vCPUs\n");

        /* Wait for the vcpu threads to quit */
        for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {
                pthread_join(vcpu_threads[vcpu_id], NULL);
                PER_VCPU_DEBUG("Joined thread for vCPU %d\n", vcpu_id);
        }

        pr_info("All vCPU threads joined\n");

        clock_gettime(CLOCK_MONOTONIC, &end);

        if (use_uffd) {
                char c;

                /* Tell the user fault fd handler threads to quit */
                for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {
                        r = write(pipefds[vcpu_id * 2 + 1], &c, 1);
                        TEST_ASSERT(r == 1, "Unable to write to pipefd");

                        pthread_join(uffd_handler_threads[vcpu_id], NULL);
                }
        }

        ts_diff = timespec_sub(end, start);
        pr_info("Total guest execution time: %ld.%.9lds\n",
                ts_diff.tv_sec, ts_diff.tv_nsec);
        pr_info("Overall demand paging rate: %f pgs/sec\n",
                guest_num_pages / ((double)ts_diff.tv_sec + (double)ts_diff.tv_nsec / 100000000.0));

        ucall_uninit(vm);
        kvm_vm_free(vm);

        free(guest_data_prototype);
        free(vcpu_threads);
        if (use_uffd) {
                free(uffd_handler_threads);
                free(uffd_args);
                free(pipefds);
        }
}

struct guest_mode {
        bool supported;
        bool enabled;
};
static struct guest_mode guest_modes[NUM_VM_MODES];

#define guest_mode_init(mode, supported, enabled) ({ \
        guest_modes[mode] = (struct guest_mode){ supported, enabled }; \
})

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

        puts("");
        printf("usage: %s [-h] [-m mode] [-u] [-d uffd_delay_usec]\n"
               "          [-b memory] [-v vcpus]\n", name);
        printf(" -m: specify the guest mode ID to test\n"
               "     (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),
                       guest_modes[i].supported ? " (supported)" : "");
        }
        printf(" -u: use User Fault FD to handle vCPU page\n"
               "     faults.\n");
        printf(" -d: add a delay in usec to the User Fault\n"
               "     FD handler to simulate demand paging\n"
               "     overheads. Ignored without -u.\n");
        printf(" -b: specify the size of the memory region which should be\n"
               "     demand paged by each vCPU. e.g. 10M or 3G.\n"
               "     Default: 1G\n");
        printf(" -v: specify the number of vCPUs to run.\n");
        puts("");
        exit(0);
}

int main(int argc, char *argv[])
{
        bool mode_selected = false;
        uint64_t vcpu_memory_bytes = DEFAULT_GUEST_TEST_MEM_SIZE;
        int vcpus = 1;
        unsigned int mode;
        int opt, i;
        bool use_uffd = false;
        useconds_t uffd_delay = 0;

#ifdef __x86_64__
        guest_mode_init(VM_MODE_PXXV48_4K, true, true);
#endif
#ifdef __aarch64__
        guest_mode_init(VM_MODE_P40V48_4K, true, true);
        guest_mode_init(VM_MODE_P40V48_64K, true, true);
        {
                unsigned int limit = kvm_check_cap(KVM_CAP_ARM_VM_IPA_SIZE);

                if (limit >= 52)
                        guest_mode_init(VM_MODE_P52V48_64K, true, true);
                if (limit >= 48) {
                        guest_mode_init(VM_MODE_P48V48_4K, true, true);
                        guest_mode_init(VM_MODE_P48V48_64K, true, true);
                }
        }
#endif
#ifdef __s390x__
        guest_mode_init(VM_MODE_P40V48_4K, true, true);
#endif

        while ((opt = getopt(argc, argv, "hm:ud:b:v:")) != -1) {
                switch (opt) {
                case 'm':
                        if (!mode_selected) {
                                for (i = 0; i < NUM_VM_MODES; ++i)
                                        guest_modes[i].enabled = false;
                                mode_selected = true;
                        }
                        mode = strtoul(optarg, NULL, 10);
                        TEST_ASSERT(mode < NUM_VM_MODES,
                                    "Guest mode ID %d too big", mode);
                        guest_modes[mode].enabled = true;
                        break;
                case 'u':
                        use_uffd = true;
                        break;
                case 'd':
                        uffd_delay = strtoul(optarg, NULL, 0);
                        TEST_ASSERT(uffd_delay >= 0,
                                    "A negative UFFD delay is not supported.");
                        break;
                case 'b':
                        vcpu_memory_bytes = parse_size(optarg);
                        break;
                case 'v':
                        vcpus = atoi(optarg);
                        TEST_ASSERT(vcpus > 0,
                                    "Must have a positive number of vCPUs");
                        TEST_ASSERT(vcpus <= MAX_VCPUS,
                                    "This test does not currently support\n"
                                    "more than %d vCPUs.", MAX_VCPUS);
                        break;
                case 'h':
                default:
                        help(argv[0]);
                        break;
                }
        }

        for (i = 0; i < NUM_VM_MODES; ++i) {
                if (!guest_modes[i].enabled)
                        continue;
                TEST_ASSERT(guest_modes[i].supported,
                            "Guest mode ID %d (%s) not supported.",
                            i, vm_guest_mode_string(i));
                run_test(i, use_uffd, uffd_delay, vcpus, vcpu_memory_bytes);
        }

        return 0;
}

#else /* __NR_userfaultfd */

#warning "missing __NR_userfaultfd definition"

int main(void)
{
        print_skip("__NR_userfaultfd must be present for userfaultfd test");
        return KSFT_SKIP;
}

#endif /* __NR_userfaultfd */