// SPDX-License-Identifier: GPL-2.0-only
/*
 * KVM selftest s390x library code - CPU-related functions (page tables...)
 *
 * Copyright (C) 2019, Red Hat, Inc.
 */

#define _GNU_SOURCE /* for program_invocation_name */

#include "processor.h"
#include "kvm_util.h"
#include "../kvm_util_internal.h"

#define KVM_GUEST_PAGE_TABLE_MIN_PADDR          0x180000

#define PAGES_PER_REGION 4

void virt_pgd_alloc(struct kvm_vm *vm, uint32_t memslot)
{
        vm_paddr_t paddr;

        TEST_ASSERT(vm->page_size == 4096, "Unsupported page size: 0x%x",
                    vm->page_size);

        if (vm->pgd_created)
                return;

        paddr = vm_phy_pages_alloc(vm, PAGES_PER_REGION,
                                   KVM_GUEST_PAGE_TABLE_MIN_PADDR, memslot);
        memset(addr_gpa2hva(vm, paddr), 0xff, PAGES_PER_REGION * vm->page_size);

        vm->pgd = paddr;
        vm->pgd_created = true;
}

/*
 * Allocate 4 pages for a region/segment table (ri < 4), or one page for
 * a page table (ri == 4). Returns a suitable region/segment table entry
 * which points to the freshly allocated pages.
 */
static uint64_t virt_alloc_region(struct kvm_vm *vm, int ri, uint32_t memslot)
{
        uint64_t taddr;

        taddr = vm_phy_pages_alloc(vm,  ri < 4 ? PAGES_PER_REGION : 1,
                                   KVM_GUEST_PAGE_TABLE_MIN_PADDR, memslot);
        memset(addr_gpa2hva(vm, taddr), 0xff, PAGES_PER_REGION * vm->page_size);

        return (taddr & REGION_ENTRY_ORIGIN)
                | (((4 - ri) << 2) & REGION_ENTRY_TYPE)
                | ((ri < 4 ? (PAGES_PER_REGION - 1) : 0) & REGION_ENTRY_LENGTH);
}

/*
 * VM Virtual Page Map
 *
 * Input Args:
 *   vm - Virtual Machine
 *   gva - VM Virtual Address
 *   gpa - VM Physical Address
 *   memslot - Memory region slot for new virtual translation tables
 *
 * Output Args: None
 *
 * Return: None
 *
 * Within the VM given by vm, creates a virtual translation for the page
 * starting at vaddr to the page starting at paddr.
 */
void virt_pg_map(struct kvm_vm *vm, uint64_t gva, uint64_t gpa,
                 uint32_t memslot)
{
        int ri, idx;
        uint64_t *entry;

        TEST_ASSERT((gva % vm->page_size) == 0,
                "Virtual address not on page boundary,\n"
                "  vaddr: 0x%lx vm->page_size: 0x%x",
                gva, vm->page_size);
        TEST_ASSERT(sparsebit_is_set(vm->vpages_valid,
                (gva >> vm->page_shift)),
                "Invalid virtual address, vaddr: 0x%lx",
                gva);
        TEST_ASSERT((gpa % vm->page_size) == 0,
                "Physical address not on page boundary,\n"
                "  paddr: 0x%lx vm->page_size: 0x%x",
                gva, vm->page_size);
        TEST_ASSERT((gpa >> vm->page_shift) <= vm->max_gfn,
                "Physical address beyond beyond maximum supported,\n"
                "  paddr: 0x%lx vm->max_gfn: 0x%lx vm->page_size: 0x%x",
                gva, vm->max_gfn, vm->page_size);

        /* Walk through region and segment tables */
        entry = addr_gpa2hva(vm, vm->pgd);
        for (ri = 1; ri <= 4; ri++) {
                idx = (gva >> (64 - 11 * ri)) & 0x7ffu;
                if (entry[idx] & REGION_ENTRY_INVALID)
                        entry[idx] = virt_alloc_region(vm, ri, memslot);
                entry = addr_gpa2hva(vm, entry[idx] & REGION_ENTRY_ORIGIN);
        }

        /* Fill in page table entry */
        idx = (gva >> 12) & 0x0ffu;             /* page index */
        if (!(entry[idx] & PAGE_INVALID))
                fprintf(stderr,
                        "WARNING: PTE for gpa=0x%"PRIx64" already set!\n", gpa);
        entry[idx] = gpa;
}

/*
 * Address Guest Virtual to Guest Physical
 *
 * Input Args:
 *   vm - Virtual Machine
 *   gpa - VM virtual address
 *
 * Output Args: None
 *
 * Return:
 *   Equivalent VM physical address
 *
 * Translates the VM virtual address given by gva to a VM physical
 * address and then locates the memory region containing the VM
 * physical address, within the VM given by vm.  When found, the host
 * virtual address providing the memory to the vm physical address is
 * returned.
 * A TEST_ASSERT failure occurs if no region containing translated
 * VM virtual address exists.
 */
vm_paddr_t addr_gva2gpa(struct kvm_vm *vm, vm_vaddr_t gva)
{
        int ri, idx;
        uint64_t *entry;

        TEST_ASSERT(vm->page_size == 4096, "Unsupported page size: 0x%x",
                    vm->page_size);

        entry = addr_gpa2hva(vm, vm->pgd);
        for (ri = 1; ri <= 4; ri++) {
                idx = (gva >> (64 - 11 * ri)) & 0x7ffu;
                TEST_ASSERT(!(entry[idx] & REGION_ENTRY_INVALID),
                            "No region mapping for vm virtual address 0x%lx",
                            gva);
                entry = addr_gpa2hva(vm, entry[idx] & REGION_ENTRY_ORIGIN);
        }

        idx = (gva >> 12) & 0x0ffu;             /* page index */

        TEST_ASSERT(!(entry[idx] & PAGE_INVALID),
                    "No page mapping for vm virtual address 0x%lx", gva);

        return (entry[idx] & ~0xffful) + (gva & 0xffful);
}

static void virt_dump_ptes(FILE *stream, struct kvm_vm *vm, uint8_t indent,
                           uint64_t ptea_start)
{
        uint64_t *pte, ptea;

        for (ptea = ptea_start; ptea < ptea_start + 0x100 * 8; ptea += 8) {
                pte = addr_gpa2hva(vm, ptea);
                if (*pte & PAGE_INVALID)
                        continue;
                fprintf(stream, "%*spte @ 0x%lx: 0x%016lx\n",
                        indent, "", ptea, *pte);
        }
}

static void virt_dump_region(FILE *stream, struct kvm_vm *vm, uint8_t indent,
                             uint64_t reg_tab_addr)
{
        uint64_t addr, *entry;

        for (addr = reg_tab_addr; addr < reg_tab_addr + 0x400 * 8; addr += 8) {
                entry = addr_gpa2hva(vm, addr);
                if (*entry & REGION_ENTRY_INVALID)
                        continue;
                fprintf(stream, "%*srt%lde @ 0x%lx: 0x%016lx\n",
                        indent, "", 4 - ((*entry & REGION_ENTRY_TYPE) >> 2),
                        addr, *entry);
                if (*entry & REGION_ENTRY_TYPE) {
                        virt_dump_region(stream, vm, indent + 2,
                                         *entry & REGION_ENTRY_ORIGIN);
                } else {
                        virt_dump_ptes(stream, vm, indent + 2,
                                       *entry & REGION_ENTRY_ORIGIN);
                }
        }
}

void virt_dump(FILE *stream, struct kvm_vm *vm, uint8_t indent)
{
        if (!vm->pgd_created)
                return;

        virt_dump_region(stream, vm, indent, vm->pgd);
}

/*
 * Create a VM with reasonable defaults
 *
 * Input Args:
 *   vcpuid - The id of the single VCPU to add to the VM.
 *   extra_mem_pages - The size of extra memories to add (this will
 *                     decide how much extra space we will need to
 *                     setup the page tables using mem slot 0)
 *   guest_code - The vCPU's entry point
 *
 * Output Args: None
 *
 * Return:
 *   Pointer to opaque structure that describes the created VM.
 */
struct kvm_vm *vm_create_default(uint32_t vcpuid, uint64_t extra_mem_pages,
                                 void *guest_code)
{
        /*
         * The additional amount of pages required for the page tables is:
         * 1 * n / 256 + 4 * (n / 256) / 2048 + 4 * (n / 256) / 2048^2 + ...
         * which is definitely smaller than (n / 256) * 2.
         */
        uint64_t extra_pg_pages = extra_mem_pages / 256 * 2;
        struct kvm_vm *vm;

        vm = vm_create(VM_MODE_DEFAULT,
                       DEFAULT_GUEST_PHY_PAGES + extra_pg_pages, O_RDWR);

        kvm_vm_elf_load(vm, program_invocation_name, 0, 0);
        vm_vcpu_add_default(vm, vcpuid, guest_code);

        return vm;
}

/*
 * Adds a vCPU with reasonable defaults (i.e. a stack and initial PSW)
 *
 * Input Args:
 *   vcpuid - The id of the VCPU to add to the VM.
 *   guest_code - The vCPU's entry point
 */
void vm_vcpu_add_default(struct kvm_vm *vm, uint32_t vcpuid, void *guest_code)
{
        size_t stack_size =  DEFAULT_STACK_PGS * getpagesize();
        uint64_t stack_vaddr;
        struct kvm_regs regs;
        struct kvm_sregs sregs;
        struct kvm_run *run;

        TEST_ASSERT(vm->page_size == 4096, "Unsupported page size: 0x%x",
                    vm->page_size);

        stack_vaddr = vm_vaddr_alloc(vm, stack_size,
                                     DEFAULT_GUEST_STACK_VADDR_MIN, 0, 0);

        vm_vcpu_add(vm, vcpuid);

        /* Setup guest registers */
        vcpu_regs_get(vm, vcpuid, &regs);
        regs.gprs[15] = stack_vaddr + (DEFAULT_STACK_PGS * getpagesize()) - 160;
        vcpu_regs_set(vm, vcpuid, &regs);

        vcpu_sregs_get(vm, vcpuid, &sregs);
        sregs.crs[0] |= 0x00040000;             /* Enable floating point regs */
        sregs.crs[1] = vm->pgd | 0xf;           /* Primary region table */
        vcpu_sregs_set(vm, vcpuid, &sregs);

        run = vcpu_state(vm, vcpuid);
        run->psw_mask = 0x0400000180000000ULL;  /* DAT enabled + 64 bit mode */
        run->psw_addr = (uintptr_t)guest_code;
}

void vcpu_dump(FILE *stream, struct kvm_vm *vm, uint32_t vcpuid, uint8_t indent)
{
        struct vcpu *vcpu = vm->vcpu_head;

        fprintf(stream, "%*spstate: psw: 0x%.16llx:0x%.16llx\n",
                indent, "", vcpu->state->psw_mask, vcpu->state->psw_addr);
}