/*
 * VMware Detection code.
 *
 * Copyright (C) 2008, VMware, Inc.
 * Author : Alok N Kataria <akataria@vmware.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 * NON INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */

#include <linux/dmi.h>
#include <linux/init.h>
#include <linux/export.h>
#include <linux/clocksource.h>
#include <linux/cpu.h>
#include <linux/efi.h>
#include <linux/reboot.h>
#include <linux/static_call.h>
#include <linux/sched/cputime.h>
#include <asm/div64.h>
#include <asm/x86_init.h>
#include <asm/hypervisor.h>
#include <asm/timer.h>
#include <asm/apic.h>
#include <asm/vmware.h>
#include <asm/svm.h>

#undef pr_fmt
#define pr_fmt(fmt)     "vmware: " fmt

#define CPUID_VMWARE_INFO_LEAF               0x40000000
#define CPUID_VMWARE_FEATURES_LEAF           0x40000010

#define GETVCPU_INFO_LEGACY_X2APIC           BIT(3)
#define GETVCPU_INFO_VCPU_RESERVED           BIT(31)

#define STEALCLOCK_NOT_AVAILABLE (-1)
#define STEALCLOCK_DISABLED        0
#define STEALCLOCK_ENABLED         1

struct vmware_steal_time {
        union {
                u64 clock;      /* stolen time counter in units of vtsc */
                struct {
                        /* only for little-endian */
                        u32 clock_low;
                        u32 clock_high;
                };
        };
        u64 reserved[7];
};

static unsigned long vmware_tsc_khz __ro_after_init;
static u8 vmware_hypercall_mode     __ro_after_init;

unsigned long vmware_hypercall_slow(unsigned long cmd,
                                    unsigned long in1, unsigned long in3,
                                    unsigned long in4, unsigned long in5,
                                    u32 *out1, u32 *out2, u32 *out3,
                                    u32 *out4, u32 *out5)
{
        unsigned long out0, rbx, rcx, rdx, rsi, rdi;

        switch (vmware_hypercall_mode) {
        case CPUID_VMWARE_FEATURES_ECX_VMCALL:
                asm_inline volatile ("vmcall"
                                : "=a" (out0), "=b" (rbx), "=c" (rcx),
                                "=d" (rdx), "=S" (rsi), "=D" (rdi)
                                : "a" (VMWARE_HYPERVISOR_MAGIC),
                                "b" (in1),
                                "c" (cmd),
                                "d" (in3),
                                "S" (in4),
                                "D" (in5)
                                : "cc", "memory");
                break;
        case CPUID_VMWARE_FEATURES_ECX_VMMCALL:
                asm_inline volatile ("vmmcall"
                                : "=a" (out0), "=b" (rbx), "=c" (rcx),
                                "=d" (rdx), "=S" (rsi), "=D" (rdi)
                                : "a" (VMWARE_HYPERVISOR_MAGIC),
                                "b" (in1),
                                "c" (cmd),
                                "d" (in3),
                                "S" (in4),
                                "D" (in5)
                                : "cc", "memory");
                break;
        default:
                asm_inline volatile ("movw %[port], %%dx; inl (%%dx), %%eax"
                                : "=a" (out0), "=b" (rbx), "=c" (rcx),
                                "=d" (rdx), "=S" (rsi), "=D" (rdi)
                                : [port] "i" (VMWARE_HYPERVISOR_PORT),
                                "a" (VMWARE_HYPERVISOR_MAGIC),
                                "b" (in1),
                                "c" (cmd),
                                "d" (in3),
                                "S" (in4),
                                "D" (in5)
                                : "cc", "memory");
                break;
        }

        if (out1)
                *out1 = rbx;
        if (out2)
                *out2 = rcx;
        if (out3)
                *out3 = rdx;
        if (out4)
                *out4 = rsi;
        if (out5)
                *out5 = rdi;

        return out0;
}

static inline int __vmware_platform(void)
{
        u32 eax, ebx, ecx;

        eax = vmware_hypercall3(VMWARE_CMD_GETVERSION, 0, &ebx, &ecx);
        return eax != UINT_MAX && ebx == VMWARE_HYPERVISOR_MAGIC;
}

static unsigned long vmware_get_tsc_khz(void)
{
        return vmware_tsc_khz;
}

#ifdef CONFIG_PARAVIRT
static struct cyc2ns_data vmware_cyc2ns __ro_after_init;
static bool vmw_sched_clock __initdata = true;
static DEFINE_PER_CPU_DECRYPTED(struct vmware_steal_time, vmw_steal_time) __aligned(64);
static bool has_steal_clock;
static bool steal_acc __initdata = true; /* steal time accounting */

static __init int setup_vmw_sched_clock(char *s)
{
        vmw_sched_clock = false;
        return 0;
}
early_param("no-vmw-sched-clock", setup_vmw_sched_clock);

static __init int parse_no_stealacc(char *arg)
{
        steal_acc = false;
        return 0;
}
early_param("no-steal-acc", parse_no_stealacc);

static noinstr u64 vmware_sched_clock(void)
{
        unsigned long long ns;

        ns = mul_u64_u32_shr(rdtsc(), vmware_cyc2ns.cyc2ns_mul,
                             vmware_cyc2ns.cyc2ns_shift);
        ns -= vmware_cyc2ns.cyc2ns_offset;
        return ns;
}

static void __init vmware_cyc2ns_setup(void)
{
        struct cyc2ns_data *d = &vmware_cyc2ns;
        unsigned long long tsc_now = rdtsc();

        clocks_calc_mult_shift(&d->cyc2ns_mul, &d->cyc2ns_shift,
                               vmware_tsc_khz, NSEC_PER_MSEC, 0);
        d->cyc2ns_offset = mul_u64_u32_shr(tsc_now, d->cyc2ns_mul,
                                           d->cyc2ns_shift);

        pr_info("using clock offset of %llu ns\n", d->cyc2ns_offset);
}

static int vmware_cmd_stealclock(u32 addr_hi, u32 addr_lo)
{
        u32 info;

        return vmware_hypercall5(VMWARE_CMD_STEALCLOCK, 0, 0, addr_hi, addr_lo,
                                 &info);
}

static bool stealclock_enable(phys_addr_t pa)
{
        return vmware_cmd_stealclock(upper_32_bits(pa),
                                     lower_32_bits(pa)) == STEALCLOCK_ENABLED;
}

static int __stealclock_disable(void)
{
        return vmware_cmd_stealclock(0, 1);
}

static void stealclock_disable(void)
{
        __stealclock_disable();
}

static bool vmware_is_stealclock_available(void)
{
        return __stealclock_disable() != STEALCLOCK_NOT_AVAILABLE;
}

/**
 * vmware_steal_clock() - read the per-cpu steal clock
 * @cpu:            the cpu number whose steal clock we want to read
 *
 * The function reads the steal clock if we are on a 64-bit system, otherwise
 * reads it in parts, checking that the high part didn't change in the
 * meantime.
 *
 * Return:
 *      The steal clock reading in ns.
 */
static u64 vmware_steal_clock(int cpu)
{
        struct vmware_steal_time *steal = &per_cpu(vmw_steal_time, cpu);
        u64 clock;

        if (IS_ENABLED(CONFIG_64BIT))
                clock = READ_ONCE(steal->clock);
        else {
                u32 initial_high, low, high;

                do {
                        initial_high = READ_ONCE(steal->clock_high);
                        /* Do not reorder initial_high and high readings */
                        virt_rmb();
                        low = READ_ONCE(steal->clock_low);
                        /* Keep low reading in between */
                        virt_rmb();
                        high = READ_ONCE(steal->clock_high);
                } while (initial_high != high);

                clock = ((u64)high << 32) | low;
        }

        return mul_u64_u32_shr(clock, vmware_cyc2ns.cyc2ns_mul,
                             vmware_cyc2ns.cyc2ns_shift);
}

static void vmware_register_steal_time(void)
{
        int cpu = smp_processor_id();
        struct vmware_steal_time *st = &per_cpu(vmw_steal_time, cpu);

        if (!has_steal_clock)
                return;

        if (!stealclock_enable(slow_virt_to_phys(st))) {
                has_steal_clock = false;
                return;
        }

        pr_info("vmware-stealtime: cpu %d, pa %llx\n",
                cpu, (unsigned long long) slow_virt_to_phys(st));
}

static void vmware_disable_steal_time(void)
{
        if (!has_steal_clock)
                return;

        stealclock_disable();
}

static void vmware_guest_cpu_init(void)
{
        if (has_steal_clock)
                vmware_register_steal_time();
}

static void vmware_pv_guest_cpu_reboot(void *unused)
{
        vmware_disable_steal_time();
}

static int vmware_pv_reboot_notify(struct notifier_block *nb,
                                unsigned long code, void *unused)
{
        if (code == SYS_RESTART)
                on_each_cpu(vmware_pv_guest_cpu_reboot, NULL, 1);
        return NOTIFY_DONE;
}

static struct notifier_block vmware_pv_reboot_nb = {
        .notifier_call = vmware_pv_reboot_notify,
};

#ifdef CONFIG_SMP
static void __init vmware_smp_prepare_boot_cpu(void)
{
        vmware_guest_cpu_init();
        native_smp_prepare_boot_cpu();
}

static int vmware_cpu_online(unsigned int cpu)
{
        local_irq_disable();
        vmware_guest_cpu_init();
        local_irq_enable();
        return 0;
}

static int vmware_cpu_down_prepare(unsigned int cpu)
{
        local_irq_disable();
        vmware_disable_steal_time();
        local_irq_enable();
        return 0;
}
#endif

static __init int activate_jump_labels(void)
{
        if (has_steal_clock) {
                static_key_slow_inc(&paravirt_steal_enabled);
                if (steal_acc)
                        static_key_slow_inc(&paravirt_steal_rq_enabled);
        }

        return 0;
}
arch_initcall(activate_jump_labels);

static void __init vmware_paravirt_ops_setup(void)
{
        pv_info.name = "VMware hypervisor";
        pv_ops.cpu.io_delay = paravirt_nop;

        if (vmware_tsc_khz == 0)
                return;

        vmware_cyc2ns_setup();

        if (vmw_sched_clock)
                paravirt_set_sched_clock(vmware_sched_clock);

        if (vmware_is_stealclock_available()) {
                has_steal_clock = true;
                static_call_update(pv_steal_clock, vmware_steal_clock);

                /* We use reboot notifier only to disable steal clock */
                register_reboot_notifier(&vmware_pv_reboot_nb);

#ifdef CONFIG_SMP
                smp_ops.smp_prepare_boot_cpu =
                        vmware_smp_prepare_boot_cpu;
                if (cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
                                              "x86/vmware:online",
                                              vmware_cpu_online,
                                              vmware_cpu_down_prepare) < 0)
                        pr_err("vmware_guest: Failed to install cpu hotplug callbacks\n");
#else
                vmware_guest_cpu_init();
#endif
        }
}
#else
#define vmware_paravirt_ops_setup() do {} while (0)
#endif

/*
 * VMware hypervisor takes care of exporting a reliable TSC to the guest.
 * Still, due to timing difference when running on virtual cpus, the TSC can
 * be marked as unstable in some cases. For example, the TSC sync check at
 * bootup can fail due to a marginal offset between vcpus' TSCs (though the
 * TSCs do not drift from each other).  Also, the ACPI PM timer clocksource
 * is not suitable as a watchdog when running on a hypervisor because the
 * kernel may miss a wrap of the counter if the vcpu is descheduled for a
 * long time. To skip these checks at runtime we set these capability bits,
 * so that the kernel could just trust the hypervisor with providing a
 * reliable virtual TSC that is suitable for timekeeping.
 */
static void __init vmware_set_capabilities(void)
{
        setup_force_cpu_cap(X86_FEATURE_CONSTANT_TSC);
        setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);
        if (vmware_tsc_khz)
                setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ);
        if (vmware_hypercall_mode == CPUID_VMWARE_FEATURES_ECX_VMCALL)
                setup_force_cpu_cap(X86_FEATURE_VMCALL);
        else if (vmware_hypercall_mode == CPUID_VMWARE_FEATURES_ECX_VMMCALL)
                setup_force_cpu_cap(X86_FEATURE_VMW_VMMCALL);
}

static void __init vmware_platform_setup(void)
{
        u32 eax, ebx, ecx;
        u64 lpj, tsc_khz;

        eax = vmware_hypercall3(VMWARE_CMD_GETHZ, UINT_MAX, &ebx, &ecx);

        if (ebx != UINT_MAX) {
                lpj = tsc_khz = eax | (((u64)ebx) << 32);
                do_div(tsc_khz, 1000);
                WARN_ON(tsc_khz >> 32);
                pr_info("TSC freq read from hypervisor : %lu.%03lu MHz\n",
                        (unsigned long) tsc_khz / 1000,
                        (unsigned long) tsc_khz % 1000);

                if (!preset_lpj) {
                        do_div(lpj, HZ);
                        preset_lpj = lpj;
                }

                vmware_tsc_khz = tsc_khz;
                x86_platform.calibrate_tsc = vmware_get_tsc_khz;
                x86_platform.calibrate_cpu = vmware_get_tsc_khz;

#ifdef CONFIG_X86_LOCAL_APIC
                /* Skip lapic calibration since we know the bus frequency. */
                lapic_timer_period = ecx / HZ;
                pr_info("Host bus clock speed read from hypervisor : %u Hz\n",
                        ecx);
#endif
        } else {
                pr_warn("Failed to get TSC freq from the hypervisor\n");
        }

        if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP) && !efi_enabled(EFI_BOOT))
                x86_init.mpparse.find_mptable = mpparse_find_mptable;

        vmware_paravirt_ops_setup();

#ifdef CONFIG_X86_IO_APIC
        no_timer_check = 1;
#endif

        vmware_set_capabilities();
}

static u8 __init vmware_select_hypercall(void)
{
        int eax, ebx, ecx, edx;

        cpuid(CPUID_VMWARE_FEATURES_LEAF, &eax, &ebx, &ecx, &edx);
        return (ecx & (CPUID_VMWARE_FEATURES_ECX_VMMCALL |
                       CPUID_VMWARE_FEATURES_ECX_VMCALL));
}

/*
 * While checking the dmi string information, just checking the product
 * serial key should be enough, as this will always have a VMware
 * specific string when running under VMware hypervisor.
 * If !boot_cpu_has(X86_FEATURE_HYPERVISOR), vmware_hypercall_mode
 * intentionally defaults to 0.
 */
static u32 __init vmware_platform(void)
{
        if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
                unsigned int eax;
                unsigned int hyper_vendor_id[3];

                cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &hyper_vendor_id[0],
                      &hyper_vendor_id[1], &hyper_vendor_id[2]);
                if (!memcmp(hyper_vendor_id, "VMwareVMware", 12)) {
                        if (eax >= CPUID_VMWARE_FEATURES_LEAF)
                                vmware_hypercall_mode =
                                        vmware_select_hypercall();

                        pr_info("hypercall mode: 0x%02x\n",
                                (unsigned int) vmware_hypercall_mode);

                        return CPUID_VMWARE_INFO_LEAF;
                }
        } else if (dmi_available && dmi_name_in_serial("VMware") &&
                   __vmware_platform())
                return 1;

        return 0;
}

/* Checks if hypervisor supports x2apic without VT-D interrupt remapping. */
static bool __init vmware_legacy_x2apic_available(void)
{
        u32 eax;

        eax = vmware_hypercall1(VMWARE_CMD_GETVCPU_INFO, 0);
        return !(eax & GETVCPU_INFO_VCPU_RESERVED) &&
                (eax & GETVCPU_INFO_LEGACY_X2APIC);
}

#ifdef CONFIG_INTEL_TDX_GUEST
/*
 * TDCALL[TDG.VP.VMCALL] uses %rax (arg0) and %rcx (arg2). Therefore,
 * we remap those registers to %r12 and %r13, respectively.
 */
unsigned long vmware_tdx_hypercall(unsigned long cmd,
                                   unsigned long in1, unsigned long in3,
                                   unsigned long in4, unsigned long in5,
                                   u32 *out1, u32 *out2, u32 *out3,
                                   u32 *out4, u32 *out5)
{
        struct tdx_module_args args = {};

        if (!hypervisor_is_type(X86_HYPER_VMWARE)) {
                pr_warn_once("Incorrect usage\n");
                return ULONG_MAX;
        }

        if (cmd & ~VMWARE_CMD_MASK) {
                pr_warn_once("Out of range command %lx\n", cmd);
                return ULONG_MAX;
        }

        args.rbx = in1;
        args.rdx = in3;
        args.rsi = in4;
        args.rdi = in5;
        args.r10 = VMWARE_TDX_VENDOR_LEAF;
        args.r11 = VMWARE_TDX_HCALL_FUNC;
        args.r12 = VMWARE_HYPERVISOR_MAGIC;
        args.r13 = cmd;
        /* CPL */
        args.r15 = 0;

        __tdx_hypercall(&args);

        if (out1)
                *out1 = args.rbx;
        if (out2)
                *out2 = args.r13;
        if (out3)
                *out3 = args.rdx;
        if (out4)
                *out4 = args.rsi;
        if (out5)
                *out5 = args.rdi;

        return args.r12;
}
EXPORT_SYMBOL_GPL(vmware_tdx_hypercall);
#endif

#ifdef CONFIG_AMD_MEM_ENCRYPT
static void vmware_sev_es_hcall_prepare(struct ghcb *ghcb,
                                        struct pt_regs *regs)
{
        /* Copy VMWARE specific Hypercall parameters to the GHCB */
        ghcb_set_rip(ghcb, regs->ip);
        ghcb_set_rbx(ghcb, regs->bx);
        ghcb_set_rcx(ghcb, regs->cx);
        ghcb_set_rdx(ghcb, regs->dx);
        ghcb_set_rsi(ghcb, regs->si);
        ghcb_set_rdi(ghcb, regs->di);
        ghcb_set_rbp(ghcb, regs->bp);
}

static bool vmware_sev_es_hcall_finish(struct ghcb *ghcb, struct pt_regs *regs)
{
        if (!(ghcb_rbx_is_valid(ghcb) &&
              ghcb_rcx_is_valid(ghcb) &&
              ghcb_rdx_is_valid(ghcb) &&
              ghcb_rsi_is_valid(ghcb) &&
              ghcb_rdi_is_valid(ghcb) &&
              ghcb_rbp_is_valid(ghcb)))
                return false;

        regs->bx = ghcb_get_rbx(ghcb);
        regs->cx = ghcb_get_rcx(ghcb);
        regs->dx = ghcb_get_rdx(ghcb);
        regs->si = ghcb_get_rsi(ghcb);
        regs->di = ghcb_get_rdi(ghcb);
        regs->bp = ghcb_get_rbp(ghcb);

        return true;
}
#endif

const __initconst struct hypervisor_x86 x86_hyper_vmware = {
        .name                           = "VMware",
        .detect                         = vmware_platform,
        .type                           = X86_HYPER_VMWARE,
        .init.init_platform             = vmware_platform_setup,
        .init.x2apic_available          = vmware_legacy_x2apic_available,
#ifdef CONFIG_AMD_MEM_ENCRYPT
        .runtime.sev_es_hcall_prepare   = vmware_sev_es_hcall_prepare,
        .runtime.sev_es_hcall_finish    = vmware_sev_es_hcall_finish,
#endif
};