// SPDX-License-Identifier: GPL-2.0
/*
 * Jailhouse paravirt_ops implementation
 *
 * Copyright (c) Siemens AG, 2015-2017
 *
 * Authors:
 *  Jan Kiszka <jan.kiszka@siemens.com>
 */

#include <linux/acpi_pmtmr.h>
#include <linux/kernel.h>
#include <linux/reboot.h>
#include <linux/serial_8250.h>
#include <asm/apic.h>
#include <asm/io_apic.h>
#include <asm/acpi.h>
#include <asm/cpu.h>
#include <asm/hypervisor.h>
#include <asm/i8259.h>
#include <asm/irqdomain.h>
#include <asm/pci_x86.h>
#include <asm/reboot.h>
#include <asm/setup.h>
#include <asm/jailhouse_para.h>

static struct jailhouse_setup_data setup_data;
#define SETUP_DATA_V1_LEN       (sizeof(setup_data.hdr) + sizeof(setup_data.v1))
#define SETUP_DATA_V2_LEN       (SETUP_DATA_V1_LEN + sizeof(setup_data.v2))

static unsigned int precalibrated_tsc_khz;

static void jailhouse_setup_irq(unsigned int irq)
{
        struct mpc_intsrc mp_irq = {
                .type           = MP_INTSRC,
                .irqtype        = mp_INT,
                .irqflag        = MP_IRQPOL_ACTIVE_HIGH | MP_IRQTRIG_EDGE,
                .srcbusirq      = irq,
                .dstirq         = irq,
        };
        mp_save_irq(&mp_irq);
}

static uint32_t jailhouse_cpuid_base(void)
{
        if (boot_cpu_data.cpuid_level < 0 ||
            !boot_cpu_has(X86_FEATURE_HYPERVISOR))
                return 0;

        return hypervisor_cpuid_base("Jailhouse\0\0\0", 0);
}

static uint32_t __init jailhouse_detect(void)
{
        return jailhouse_cpuid_base();
}

static void jailhouse_get_wallclock(struct timespec64 *now)
{
        memset(now, 0, sizeof(*now));
}

static void __init jailhouse_timer_init(void)
{
        lapic_timer_period = setup_data.v1.apic_khz * (1000 / HZ);
}

static unsigned long jailhouse_get_tsc(void)
{
        return precalibrated_tsc_khz;
}

static void __init jailhouse_x2apic_init(void)
{
#ifdef CONFIG_X86_X2APIC
        if (!x2apic_enabled())
                return;
        /*
         * We do not have access to IR inside Jailhouse non-root cells.  So
         * we have to run in physical mode.
         */
        x2apic_phys = 1;
        /*
         * This will trigger the switch to apic_x2apic_phys.  Empty OEM IDs
         * ensure that only this APIC driver picks up the call.
         */
        default_acpi_madt_oem_check("", "");
#endif
}

static void __init jailhouse_get_smp_config(unsigned int early)
{
        struct ioapic_domain_cfg ioapic_cfg = {
                .type = IOAPIC_DOMAIN_STRICT,
                .ops = &mp_ioapic_irqdomain_ops,
        };
        unsigned int cpu;

        jailhouse_x2apic_init();

        register_lapic_address(0xfee00000);

        for (cpu = 0; cpu < setup_data.v1.num_cpus; cpu++) {
                generic_processor_info(setup_data.v1.cpu_ids[cpu],
                                       boot_cpu_apic_version);
        }

        smp_found_config = 1;

        if (setup_data.v1.standard_ioapic) {
                mp_register_ioapic(0, 0xfec00000, gsi_top, &ioapic_cfg);

                if (IS_ENABLED(CONFIG_SERIAL_8250) &&
                    setup_data.hdr.version < 2) {
                        /* Register 1:1 mapping for legacy UART IRQs 3 and 4 */
                        jailhouse_setup_irq(3);
                        jailhouse_setup_irq(4);
                }
        }
}

static void jailhouse_no_restart(void)
{
        pr_notice("Jailhouse: Restart not supported, halting\n");
        machine_halt();
}

static int __init jailhouse_pci_arch_init(void)
{
        pci_direct_init(1);

        /*
         * There are no bridges on the virtual PCI root bus under Jailhouse,
         * thus no other way to discover all devices than a full scan.
         * Respect any overrides via the command line, though.
         */
        if (pcibios_last_bus < 0)
                pcibios_last_bus = 0xff;

#ifdef CONFIG_PCI_MMCONFIG
        if (setup_data.v1.pci_mmconfig_base) {
                pci_mmconfig_add(0, 0, pcibios_last_bus,
                                 setup_data.v1.pci_mmconfig_base);
                pci_mmcfg_arch_init();
        }
#endif

        return 0;
}

#ifdef CONFIG_SERIAL_8250
static inline bool jailhouse_uart_enabled(unsigned int uart_nr)
{
        return setup_data.v2.flags & BIT(uart_nr);
}

static void jailhouse_serial_fixup(int port, struct uart_port *up,
                                   u32 *capabilities)
{
        static const u16 pcuart_base[] = {0x3f8, 0x2f8, 0x3e8, 0x2e8};
        unsigned int n;

        for (n = 0; n < ARRAY_SIZE(pcuart_base); n++) {
                if (pcuart_base[n] != up->iobase)
                        continue;

                if (jailhouse_uart_enabled(n)) {
                        pr_info("Enabling UART%u (port 0x%lx)\n", n,
                                up->iobase);
                        jailhouse_setup_irq(up->irq);
                } else {
                        /* Deactivate UART if access isn't allowed */
                        up->iobase = 0;
                }
                break;
        }
}

static void __init jailhouse_serial_workaround(void)
{
        /*
         * There are flags inside setup_data that indicate availability of
         * platform UARTs since setup data version 2.
         *
         * In case of version 1, we don't know which UARTs belong Linux. In
         * this case, unconditionally register 1:1 mapping for legacy UART IRQs
         * 3 and 4.
         */
        if (setup_data.hdr.version > 1)
                serial8250_set_isa_configurator(jailhouse_serial_fixup);
}
#else /* !CONFIG_SERIAL_8250 */
static inline void jailhouse_serial_workaround(void)
{
}
#endif /* CONFIG_SERIAL_8250 */

static void __init jailhouse_init_platform(void)
{
        u64 pa_data = boot_params.hdr.setup_data;
        unsigned long setup_data_len;
        struct setup_data header;
        void *mapping;

        x86_init.irqs.pre_vector_init   = x86_init_noop;
        x86_init.timers.timer_init      = jailhouse_timer_init;
        x86_init.mpparse.get_smp_config = jailhouse_get_smp_config;
        x86_init.pci.arch_init          = jailhouse_pci_arch_init;

        x86_platform.calibrate_cpu      = jailhouse_get_tsc;
        x86_platform.calibrate_tsc      = jailhouse_get_tsc;
        x86_platform.get_wallclock      = jailhouse_get_wallclock;
        x86_platform.legacy.rtc         = 0;
        x86_platform.legacy.warm_reset  = 0;
        x86_platform.legacy.i8042       = X86_LEGACY_I8042_PLATFORM_ABSENT;

        legacy_pic                      = &null_legacy_pic;

        machine_ops.emergency_restart   = jailhouse_no_restart;

        while (pa_data) {
                mapping = early_memremap(pa_data, sizeof(header));
                memcpy(&header, mapping, sizeof(header));
                early_memunmap(mapping, sizeof(header));

                if (header.type == SETUP_JAILHOUSE)
                        break;

                pa_data = header.next;
        }

        if (!pa_data)
                panic("Jailhouse: No valid setup data found");

        /* setup data must at least contain the header */
        if (header.len < sizeof(setup_data.hdr))
                goto unsupported;

        pa_data += offsetof(struct setup_data, data);
        setup_data_len = min_t(unsigned long, sizeof(setup_data),
                               (unsigned long)header.len);
        mapping = early_memremap(pa_data, setup_data_len);
        memcpy(&setup_data, mapping, setup_data_len);
        early_memunmap(mapping, setup_data_len);

        if (setup_data.hdr.version == 0 ||
            setup_data.hdr.compatible_version !=
                JAILHOUSE_SETUP_REQUIRED_VERSION ||
            (setup_data.hdr.version == 1 && header.len < SETUP_DATA_V1_LEN) ||
            (setup_data.hdr.version >= 2 && header.len < SETUP_DATA_V2_LEN))
                goto unsupported;

        pmtmr_ioport = setup_data.v1.pm_timer_address;
        pr_debug("Jailhouse: PM-Timer IO Port: %#x\n", pmtmr_ioport);

        precalibrated_tsc_khz = setup_data.v1.tsc_khz;
        setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ);

        pci_probe = 0;

        /*
         * Avoid that the kernel complains about missing ACPI tables - there
         * are none in a non-root cell.
         */
        disable_acpi();

        jailhouse_serial_workaround();
        return;

unsupported:
        panic("Jailhouse: Unsupported setup data structure");
}

bool jailhouse_paravirt(void)
{
        return jailhouse_cpuid_base() != 0;
}

static bool __init jailhouse_x2apic_available(void)
{
        /*
         * The x2APIC is only available if the root cell enabled it. Jailhouse
         * does not support switching between xAPIC and x2APIC.
         */
        return x2apic_enabled();
}

const struct hypervisor_x86 x86_hyper_jailhouse __refconst = {
        .name                   = "Jailhouse",
        .detect                 = jailhouse_detect,
        .init.init_platform     = jailhouse_init_platform,
        .init.x2apic_available  = jailhouse_x2apic_available,
        .ignore_nopv            = true,
};