// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE /* for program_invocation_short_name */
#include <fcntl.h>
#include <pthread.h>
#include <sched.h>
#include <semaphore.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mman.h>

#include <linux/compiler.h>

#include <test_util.h>
#include <kvm_util.h>
#include <processor.h>

#define VCPU_ID 0

/*
 * s390x needs at least 1MB alignment, and the x86_64 MOVE/DELETE tests need a
 * 2MB sized and aligned region so that the initial region corresponds to
 * exactly one large page.
 */
#define MEM_REGION_SIZE         0x200000

#ifdef __x86_64__
/*
 * Somewhat arbitrary location and slot, intended to not overlap anything.
 */
#define MEM_REGION_GPA          0xc0000000
#define MEM_REGION_SLOT         10

static const uint64_t MMIO_VAL = 0xbeefull;

extern const uint64_t final_rip_start;
extern const uint64_t final_rip_end;

static sem_t vcpu_ready;

static inline uint64_t guest_spin_on_val(uint64_t spin_val)
{
        uint64_t val;

        do {
                val = READ_ONCE(*((uint64_t *)MEM_REGION_GPA));
        } while (val == spin_val);

        GUEST_SYNC(0);
        return val;
}

static void *vcpu_worker(void *data)
{
        struct kvm_vm *vm = data;
        struct kvm_run *run;
        struct ucall uc;
        uint64_t cmd;

        /*
         * Loop until the guest is done.  Re-enter the guest on all MMIO exits,
         * which will occur if the guest attempts to access a memslot after it
         * has been deleted or while it is being moved .
         */
        run = vcpu_state(vm, VCPU_ID);

        while (1) {
                vcpu_run(vm, VCPU_ID);

                if (run->exit_reason == KVM_EXIT_IO) {
                        cmd = get_ucall(vm, VCPU_ID, &uc);
                        if (cmd != UCALL_SYNC)
                                break;

                        sem_post(&vcpu_ready);
                        continue;
                }

                if (run->exit_reason != KVM_EXIT_MMIO)
                        break;

                TEST_ASSERT(!run->mmio.is_write, "Unexpected exit mmio write");
                TEST_ASSERT(run->mmio.len == 8,
                            "Unexpected exit mmio size = %u", run->mmio.len);

                TEST_ASSERT(run->mmio.phys_addr == MEM_REGION_GPA,
                            "Unexpected exit mmio address = 0x%llx",
                            run->mmio.phys_addr);
                memcpy(run->mmio.data, &MMIO_VAL, 8);
        }

        if (run->exit_reason == KVM_EXIT_IO && cmd == UCALL_ABORT)
                TEST_FAIL("%s at %s:%ld, val = %lu", (const char *)uc.args[0],
                          __FILE__, uc.args[1], uc.args[2]);

        return NULL;
}

static void wait_for_vcpu(void)
{
        struct timespec ts;

        TEST_ASSERT(!clock_gettime(CLOCK_REALTIME, &ts),
                    "clock_gettime() failed: %d\n", errno);

        ts.tv_sec += 2;
        TEST_ASSERT(!sem_timedwait(&vcpu_ready, &ts),
                    "sem_timedwait() failed: %d\n", errno);

        /* Wait for the vCPU thread to reenter the guest. */
        usleep(100000);
}

static struct kvm_vm *spawn_vm(pthread_t *vcpu_thread, void *guest_code)
{
        struct kvm_vm *vm;
        uint64_t *hva;
        uint64_t gpa;

        vm = vm_create_default(VCPU_ID, 0, guest_code);

        vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());

        vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS_THP,
                                    MEM_REGION_GPA, MEM_REGION_SLOT,
                                    MEM_REGION_SIZE / getpagesize(), 0);

        /*
         * Allocate and map two pages so that the GPA accessed by guest_code()
         * stays valid across the memslot move.
         */
        gpa = vm_phy_pages_alloc(vm, 2, MEM_REGION_GPA, MEM_REGION_SLOT);
        TEST_ASSERT(gpa == MEM_REGION_GPA, "Failed vm_phy_pages_alloc\n");

        virt_map(vm, MEM_REGION_GPA, MEM_REGION_GPA, 2, 0);

        /* Ditto for the host mapping so that both pages can be zeroed. */
        hva = addr_gpa2hva(vm, MEM_REGION_GPA);
        memset(hva, 0, 2 * 4096);

        pthread_create(vcpu_thread, NULL, vcpu_worker, vm);

        /* Ensure the guest thread is spun up. */
        wait_for_vcpu();

        return vm;
}


static void guest_code_move_memory_region(void)
{
        uint64_t val;

        GUEST_SYNC(0);

        /*
         * Spin until the memory region is moved to a misaligned address.  This
         * may or may not trigger MMIO, as the window where the memslot is
         * invalid is quite small.
         */
        val = guest_spin_on_val(0);
        GUEST_ASSERT_1(val == 1 || val == MMIO_VAL, val);

        /* Spin until the memory region is realigned. */
        val = guest_spin_on_val(MMIO_VAL);
        GUEST_ASSERT_1(val == 1, val);

        GUEST_DONE();
}

static void test_move_memory_region(void)
{
        pthread_t vcpu_thread;
        struct kvm_vm *vm;
        uint64_t *hva;

        vm = spawn_vm(&vcpu_thread, guest_code_move_memory_region);

        hva = addr_gpa2hva(vm, MEM_REGION_GPA);

        /*
         * Shift the region's base GPA.  The guest should not see "2" as the
         * hva->gpa translation is misaligned, i.e. the guest is accessing a
         * different host pfn.
         */
        vm_mem_region_move(vm, MEM_REGION_SLOT, MEM_REGION_GPA - 4096);
        WRITE_ONCE(*hva, 2);

        /*
         * The guest _might_ see an invalid memslot and trigger MMIO, but it's
         * a tiny window.  Spin and defer the sync until the memslot is
         * restored and guest behavior is once again deterministic.
         */
        usleep(100000);

        /*
         * Note, value in memory needs to be changed *before* restoring the
         * memslot, else the guest could race the update and see "2".
         */
        WRITE_ONCE(*hva, 1);

        /* Restore the original base, the guest should see "1". */
        vm_mem_region_move(vm, MEM_REGION_SLOT, MEM_REGION_GPA);
        wait_for_vcpu();
        /* Defered sync from when the memslot was misaligned (above). */
        wait_for_vcpu();

        pthread_join(vcpu_thread, NULL);

        kvm_vm_free(vm);
}

static void guest_code_delete_memory_region(void)
{
        uint64_t val;

        GUEST_SYNC(0);

        /* Spin until the memory region is deleted. */
        val = guest_spin_on_val(0);
        GUEST_ASSERT_1(val == MMIO_VAL, val);

        /* Spin until the memory region is recreated. */
        val = guest_spin_on_val(MMIO_VAL);
        GUEST_ASSERT_1(val == 0, val);

        /* Spin until the memory region is deleted. */
        val = guest_spin_on_val(0);
        GUEST_ASSERT_1(val == MMIO_VAL, val);

        asm("1:\n\t"
            ".pushsection .rodata\n\t"
            ".global final_rip_start\n\t"
            "final_rip_start: .quad 1b\n\t"
            ".popsection");

        /* Spin indefinitely (until the code memslot is deleted). */
        guest_spin_on_val(MMIO_VAL);

        asm("1:\n\t"
            ".pushsection .rodata\n\t"
            ".global final_rip_end\n\t"
            "final_rip_end: .quad 1b\n\t"
            ".popsection");

        GUEST_ASSERT_1(0, 0);
}

static void test_delete_memory_region(void)
{
        pthread_t vcpu_thread;
        struct kvm_regs regs;
        struct kvm_run *run;
        struct kvm_vm *vm;

        vm = spawn_vm(&vcpu_thread, guest_code_delete_memory_region);

        /* Delete the memory region, the guest should not die. */
        vm_mem_region_delete(vm, MEM_REGION_SLOT);
        wait_for_vcpu();

        /* Recreate the memory region.  The guest should see "0". */
        vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS_THP,
                                    MEM_REGION_GPA, MEM_REGION_SLOT,
                                    MEM_REGION_SIZE / getpagesize(), 0);
        wait_for_vcpu();

        /* Delete the region again so that there's only one memslot left. */
        vm_mem_region_delete(vm, MEM_REGION_SLOT);
        wait_for_vcpu();

        /*
         * Delete the primary memslot.  This should cause an emulation error or
         * shutdown due to the page tables getting nuked.
         */
        vm_mem_region_delete(vm, 0);

        pthread_join(vcpu_thread, NULL);

        run = vcpu_state(vm, VCPU_ID);

        TEST_ASSERT(run->exit_reason == KVM_EXIT_SHUTDOWN ||
                    run->exit_reason == KVM_EXIT_INTERNAL_ERROR,
                    "Unexpected exit reason = %d", run->exit_reason);

        vcpu_regs_get(vm, VCPU_ID, &regs);

        /*
         * On AMD, after KVM_EXIT_SHUTDOWN the VMCB has been reinitialized already,
         * so the instruction pointer would point to the reset vector.
         */
        if (run->exit_reason == KVM_EXIT_INTERNAL_ERROR)
                TEST_ASSERT(regs.rip >= final_rip_start &&
                            regs.rip < final_rip_end,
                            "Bad rip, expected 0x%lx - 0x%lx, got 0x%llx\n",
                            final_rip_start, final_rip_end, regs.rip);

        kvm_vm_free(vm);
}

static void test_zero_memory_regions(void)
{
        struct kvm_run *run;
        struct kvm_vm *vm;

        pr_info("Testing KVM_RUN with zero added memory regions\n");

        vm = vm_create(VM_MODE_DEFAULT, 0, O_RDWR);
        vm_vcpu_add(vm, VCPU_ID);

        TEST_ASSERT(!ioctl(vm_get_fd(vm), KVM_SET_NR_MMU_PAGES, 64),
                    "KVM_SET_NR_MMU_PAGES failed, errno = %d\n", errno);
        vcpu_run(vm, VCPU_ID);

        run = vcpu_state(vm, VCPU_ID);
        TEST_ASSERT(run->exit_reason == KVM_EXIT_INTERNAL_ERROR,
                    "Unexpected exit_reason = %u\n", run->exit_reason);

        kvm_vm_free(vm);
}
#endif /* __x86_64__ */

/*
 * Test it can be added memory slots up to KVM_CAP_NR_MEMSLOTS, then any
 * tentative to add further slots should fail.
 */
static void test_add_max_memory_regions(void)
{
        int ret;
        struct kvm_vm *vm;
        uint32_t max_mem_slots;
        uint32_t slot;
        uint64_t guest_addr = 0x0;
        uint64_t mem_reg_npages;
        void *mem;

        max_mem_slots = kvm_check_cap(KVM_CAP_NR_MEMSLOTS);
        TEST_ASSERT(max_mem_slots > 0,
                    "KVM_CAP_NR_MEMSLOTS should be greater than 0");
        pr_info("Allowed number of memory slots: %i\n", max_mem_slots);

        vm = vm_create(VM_MODE_DEFAULT, 0, O_RDWR);

        mem_reg_npages = vm_calc_num_guest_pages(VM_MODE_DEFAULT, MEM_REGION_SIZE);

        /* Check it can be added memory slots up to the maximum allowed */
        pr_info("Adding slots 0..%i, each memory region with %dK size\n",
                (max_mem_slots - 1), MEM_REGION_SIZE >> 10);
        for (slot = 0; slot < max_mem_slots; slot++) {
                vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
                                            guest_addr, slot, mem_reg_npages,
                                            0);
                guest_addr += MEM_REGION_SIZE;
        }

        /* Check it cannot be added memory slots beyond the limit */
        mem = mmap(NULL, MEM_REGION_SIZE, PROT_READ | PROT_WRITE,
                   MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
        TEST_ASSERT(mem != MAP_FAILED, "Failed to mmap() host");

        ret = ioctl(vm_get_fd(vm), KVM_SET_USER_MEMORY_REGION,
                    &(struct kvm_userspace_memory_region) {slot, 0, guest_addr,
                    MEM_REGION_SIZE, (uint64_t) mem});
        TEST_ASSERT(ret == -1 && errno == EINVAL,
                    "Adding one more memory slot should fail with EINVAL");

        munmap(mem, MEM_REGION_SIZE);
        kvm_vm_free(vm);
}

int main(int argc, char *argv[])
{
#ifdef __x86_64__
        int i, loops;
#endif

        /* Tell stdout not to buffer its content */
        setbuf(stdout, NULL);

#ifdef __x86_64__
        /*
         * FIXME: the zero-memslot test fails on aarch64 and s390x because
         * KVM_RUN fails with ENOEXEC or EFAULT.
         */
        test_zero_memory_regions();
#endif

        test_add_max_memory_regions();

#ifdef __x86_64__
        if (argc > 1)
                loops = atoi(argv[1]);
        else
                loops = 10;

        pr_info("Testing MOVE of in-use region, %d loops\n", loops);
        for (i = 0; i < loops; i++)
                test_move_memory_region();

        pr_info("Testing DELETE of in-use region, %d loops\n", loops);
        for (i = 0; i < loops; i++)
                test_delete_memory_region();
#endif

        return 0;
}