/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2008, 2013 Citrix Systems, Inc.
 * Copyright (c) 2012 Spectra Logic Corporation
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/linker.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/smp.h>
#include <sys/systm.h>

#include <vm/vm.h>
#include <vm/pmap.h>
#include <vm/vm_param.h>

#include <dev/pci/pcivar.h>

#include <machine/_inttypes.h>
#include <machine/cpufunc.h>
#include <machine/cpu.h>
#include <machine/md_var.h>
#include <machine/metadata.h>
#include <machine/pc/bios.h>
#include <machine/smp.h>

#include <x86/apicreg.h>

#include <xen/xen-os.h>
#include <xen/error.h>
#include <xen/features.h>
#include <xen/gnttab.h>
#include <xen/hypervisor.h>
#include <xen/hvm.h>
#include <xen/xen_intr.h>

#include <contrib/xen/arch-x86/cpuid.h>
#include <contrib/xen/hvm/params.h>
#include <contrib/xen/vcpu.h>

/*--------------------------- Forward Declarations ---------------------------*/
static void xen_hvm_cpu_init(void);

/*-------------------------------- Global Data -------------------------------*/
#ifdef SMP
struct cpu_ops xen_hvm_cpu_ops = {
        .cpu_init       = xen_hvm_cpu_init,
        .cpu_resume     = xen_hvm_cpu_init
};
#endif

static MALLOC_DEFINE(M_XENHVM, "xen_hvm", "Xen HVM PV Support");

/**
 * If non-zero, the hypervisor has been configured to use a direct
 * IDT event callback for interrupt injection.
 */
int xen_vector_callback_enabled;

/**
 * Signal whether the vector injected for the event channel upcall requires to
 * be EOI'ed on the local APIC.
 */
bool xen_evtchn_needs_ack;

/*------------------------------- Per-CPU Data -------------------------------*/
DPCPU_DECLARE(struct vcpu_info *, vcpu_info);

/*------------------------------ Sysctl tunables -----------------------------*/
int xen_disable_pv_disks = 0;
int xen_disable_pv_nics = 0;
TUNABLE_INT("hw.xen.disable_pv_disks", &xen_disable_pv_disks);
TUNABLE_INT("hw.xen.disable_pv_nics", &xen_disable_pv_nics);

/*---------------------- XEN Hypervisor Probe and Setup ----------------------*/

void xen_emergency_print(const char *str, size_t size)
{
        outsb(XEN_HVM_DEBUGCONS_IOPORT, str, size);
}

static void
hypervisor_quirks(unsigned int major, unsigned int minor)
{
#ifdef SMP
        if (((major < 4) || (major == 4 && minor <= 5)) &&
            msix_disable_migration == -1) {
                /*
                 * Xen hypervisors prior to 4.6.0 do not properly
                 * handle updates to enabled MSI-X table entries,
                 * so disable MSI-X interrupt migration in that
                 * case.
                 */
                if (bootverbose)
                        printf(
"Disabling MSI-X interrupt migration due to Xen hypervisor bug.\n"
"Set machdep.msix_disable_migration=0 to forcefully enable it.\n");
                msix_disable_migration = 1;
        }
#endif
}

static void
hypervisor_version(void)
{
        uint32_t regs[4];
        int major, minor;

        do_cpuid(hv_base + 1, regs);

        major = regs[0] >> 16;
        minor = regs[0] & 0xffff;
        printf("XEN: Hypervisor version %d.%d detected.\n", major, minor);

        hypervisor_quirks(major, minor);
}

/*
 * Translate linear to physical address when still running on the bootloader
 * created page-tables.
 */
static vm_paddr_t
early_init_vtop(void *addr)
{

        /*
         * Using a KASSERT won't print anything, as this is before console
         * initialization.
         */
        if (__predict_false((uintptr_t)addr < KERNBASE)) {
                xc_printf("invalid linear address: %p\n", addr);
                halt();
        }

        return ((uintptr_t)addr - KERNBASE
#ifdef __amd64__
            + kernphys - KERNLOAD
#endif
            );
}

static int
map_shared_info(void)
{
        /*
         * TODO shared info page should be mapped in an unpopulated (IOW:
         * non-RAM) address.  But finding one at this point in boot is
         * complicated, hence re-use a RAM address for the time being.  This
         * sadly causes super-page shattering in the second stage translation
         * page tables.
         */
        static union {
                shared_info_t shared_info;
                uint8_t raw[PAGE_SIZE];
        } shared_page __attribute__((aligned(PAGE_SIZE)));
        static struct xen_add_to_physmap xatp = {
            .domid = DOMID_SELF,
            .space = XENMAPSPACE_shared_info,
        };
        int rc;

        _Static_assert(sizeof(shared_page) == PAGE_SIZE,
            "invalid Xen shared_info struct size");

        if (xatp.gpfn == 0)
                xatp.gpfn = atop(early_init_vtop(&shared_page.shared_info));

        rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
        if (rc != 0) {
                xc_printf("cannot map shared info page: %d\n", rc);
                HYPERVISOR_shared_info = NULL;
        } else if (HYPERVISOR_shared_info == NULL)
                HYPERVISOR_shared_info = &shared_page.shared_info;

        return (rc);
}

static void
fixup_console(void)
{
        struct xen_platform_op op = {
                .cmd = XENPF_get_dom0_console,
        };
        xenpf_dom0_console_t *console = &op.u.dom0_console;
        union {
                struct efi_fb efi;
                struct vbe_fb vbe;
        } *fb = NULL;
        int size;

        size = HYPERVISOR_platform_op(&op);
        if (size < 0) {
                xc_printf("Failed to get video console info: %d\n", size);
                return;
        }

        switch (console->video_type) {
        case XEN_VGATYPE_VESA_LFB:
                fb = (__typeof__ (fb))preload_search_info(preload_kmdp,
                    MODINFO_METADATA | MODINFOMD_VBE_FB);

                if (fb == NULL) {
                        xc_printf("No VBE FB in kernel metadata\n");
                        return;
                }

                _Static_assert(offsetof(struct vbe_fb, fb_bpp) ==
                    offsetof(struct efi_fb, fb_mask_reserved) +
                    sizeof(fb->efi.fb_mask_reserved),
                    "Bad structure overlay\n");
                fb->vbe.fb_bpp = console->u.vesa_lfb.bits_per_pixel;
                /* FALLTHROUGH */
        case XEN_VGATYPE_EFI_LFB:
                if (fb == NULL) {
                        fb = (__typeof__ (fb))preload_search_info(preload_kmdp,
                            MODINFO_METADATA | MODINFOMD_EFI_FB);
                        if (fb == NULL) {
                                xc_printf("No EFI FB in kernel metadata\n");
                                return;
                        }
                }

                fb->efi.fb_addr = console->u.vesa_lfb.lfb_base;
                if (size >
                    offsetof(xenpf_dom0_console_t, u.vesa_lfb.ext_lfb_base))
                        fb->efi.fb_addr |=
                            (uint64_t)console->u.vesa_lfb.ext_lfb_base << 32;
                fb->efi.fb_size = console->u.vesa_lfb.lfb_size << 16;
                fb->efi.fb_height = console->u.vesa_lfb.height;
                fb->efi.fb_width = console->u.vesa_lfb.width;
                fb->efi.fb_stride = (console->u.vesa_lfb.bytes_per_line << 3) /
                    console->u.vesa_lfb.bits_per_pixel;
#define FBMASK(c) \
    ((~0u << console->u.vesa_lfb.c ## _pos) & \
    (~0u >> (32 - console->u.vesa_lfb.c ## _pos - \
    console->u.vesa_lfb.c ## _size)))
                fb->efi.fb_mask_red = FBMASK(red);
                fb->efi.fb_mask_green = FBMASK(green);
                fb->efi.fb_mask_blue = FBMASK(blue);
                fb->efi.fb_mask_reserved = FBMASK(rsvd);
#undef FBMASK
                break;

        default:
                xc_printf("Video console type unsupported\n");
                return;
        }
}

/* Early initialization when running as a Xen guest. */
void
xen_early_init(void)
{
        uint32_t regs[4];
        int rc;

        if (hv_high < hv_base + 2) {
                xc_printf("Invalid maximum leaves for hv_base\n");
                vm_guest = VM_GUEST_VM;
                return;
        }

        /* Find the hypercall pages. */
        do_cpuid(hv_base + 2, regs);
        if (regs[0] != 1) {
                xc_printf("Invalid number of hypercall pages %u\n",
                    regs[0]);
                vm_guest = VM_GUEST_VM;
                return;
        }

        wrmsr(regs[1], early_init_vtop(&hypercall_page));

        rc = map_shared_info();
        if (rc != 0) {
                vm_guest = VM_GUEST_VM;
                return;
        }

        if (xen_initial_domain())
            /* Fixup video console information in case Xen changed the mode. */
            fixup_console();
}

static int
set_percpu_callback(unsigned int vcpu)
{
        struct xen_hvm_evtchn_upcall_vector vec;
        int error;

        vec.vcpu = vcpu;
        vec.vector = IDT_EVTCHN;
        error = HYPERVISOR_hvm_op(HVMOP_set_evtchn_upcall_vector, &vec);

        return (error != 0 ? xen_translate_error(error) : 0);
}

/*
 * Tell the hypervisor how to contact us for event channel callbacks.
 */
void
xen_hvm_set_callback(device_t dev)
{
        struct xen_hvm_param xhp;
        int irq;

        if (xen_vector_callback_enabled)
                return;

        xhp.domid = DOMID_SELF;
        xhp.index = HVM_PARAM_CALLBACK_IRQ;
        if (xen_feature(XENFEAT_hvm_callback_vector) != 0) {
                int error;

                error = set_percpu_callback(0);
                if (error == 0) {
                        xen_evtchn_needs_ack = true;
                        /* Trick toolstack to think we are enlightened */
                        xhp.value = 1;
                } else
                        xhp.value = HVM_CALLBACK_VECTOR(IDT_EVTCHN);
                error = HYPERVISOR_hvm_op(HVMOP_set_param, &xhp);
                if (error == 0) {
                        xen_vector_callback_enabled = 1;
                        return;
                } else if (xen_evtchn_needs_ack)
                        panic("Unable to setup fake HVM param: %d", error);

                printf("Xen HVM callback vector registration failed (%d). "
                    "Falling back to emulated device interrupt\n", error);
        }
        xen_vector_callback_enabled = 0;
        if (dev == NULL) {
                /*
                 * Called from early boot or resume.
                 * xenpci will invoke us again later.
                 */
                return;
        }

        irq = pci_get_irq(dev);
        if (irq < 16) {
                xhp.value = HVM_CALLBACK_GSI(irq);
        } else {
                u_int slot;
                u_int pin;

                slot = pci_get_slot(dev);
                pin = pci_get_intpin(dev) - 1;
                xhp.value = HVM_CALLBACK_PCI_INTX(slot, pin);
        }

        if (HYPERVISOR_hvm_op(HVMOP_set_param, &xhp) != 0)
                panic("Can't set evtchn callback");
}

#define XEN_MAGIC_IOPORT 0x10
enum {
        XMI_MAGIC                        = 0x49d2,
        XMI_UNPLUG_IDE_DISKS             = 0x01,
        XMI_UNPLUG_NICS                  = 0x02,
        XMI_UNPLUG_IDE_EXCEPT_PRI_MASTER = 0x04
};

static void
xen_hvm_disable_emulated_devices(void)
{
        u_short disable_devs = 0;

        if (xen_pv_domain()) {
                /*
                 * No emulated devices in the PV case, so no need to unplug
                 * anything.
                 */
                if (xen_disable_pv_disks != 0 || xen_disable_pv_nics != 0)
                        printf("PV devices cannot be disabled in PV guests\n");
                return;
        }

        if (inw(XEN_MAGIC_IOPORT) != XMI_MAGIC)
                return;

        if (xen_disable_pv_disks == 0) {
                if (bootverbose)
                        printf("XEN: disabling emulated disks\n");
                disable_devs |= XMI_UNPLUG_IDE_DISKS;
        }
        if (xen_disable_pv_nics == 0) {
                if (bootverbose)
                        printf("XEN: disabling emulated nics\n");
                disable_devs |= XMI_UNPLUG_NICS;
        }

        if (disable_devs != 0)
                outw(XEN_MAGIC_IOPORT, disable_devs);
}

static void
xen_hvm_init(enum xen_hvm_init_type init_type)
{
        unsigned int i;

        if (!xen_domain() ||
            init_type == XEN_HVM_INIT_CANCELLED_SUSPEND)
                return;

        hypervisor_version();

        switch (init_type) {
        case XEN_HVM_INIT_LATE:
                setup_xen_features();
#ifdef SMP
                cpu_ops = xen_hvm_cpu_ops;
#endif
                break;
        case XEN_HVM_INIT_RESUME:
                /* Clear stale vcpu_info. */
                CPU_FOREACH(i)
                        DPCPU_ID_SET(i, vcpu_info, NULL);

                if (map_shared_info() != 0)
                        panic("cannot map Xen shared info page");

                break;
        default:
                panic("Unsupported HVM initialization type");
        }

        xen_vector_callback_enabled = 0;
        xen_evtchn_needs_ack = false;
        xen_hvm_set_callback(NULL);

        xen_hvm_disable_emulated_devices();
} 

void
xen_hvm_suspend(void)
{
}

void
xen_hvm_resume(bool suspend_cancelled)
{

        xen_hvm_init(suspend_cancelled ?
            XEN_HVM_INIT_CANCELLED_SUSPEND : XEN_HVM_INIT_RESUME);

        /* Register vcpu_info area for CPU#0. */
        xen_hvm_cpu_init();
}

static void
xen_hvm_sysinit(void *arg __unused)
{
        xen_hvm_init(XEN_HVM_INIT_LATE);
}
SYSINIT(xen_hvm_init, SI_SUB_HYPERVISOR, SI_ORDER_FIRST, xen_hvm_sysinit, NULL);

static void
xen_hvm_cpu_init(void)
{
        uint32_t regs[4];
        int rc;

        if (!xen_domain())
                return;

        if (DPCPU_GET(vcpu_info) != NULL) {
                /*
                 * vcpu_info is already set.  We're resuming
                 * from a failed migration and our pre-suspend
                 * configuration is still valid.
                 */
                return;
        }

        /*
         * Set vCPU ID. If available fetch the ID from CPUID, if not just use
         * the ACPI ID.
         */
        KASSERT(hv_base != 0, ("Invalid base Xen CPUID leaf"));
        cpuid_count(hv_base + 4, 0, regs);
        KASSERT((regs[0] & XEN_HVM_CPUID_VCPU_ID_PRESENT) ||
            !xen_pv_domain(),
            ("Xen PV domain without vcpu_id in cpuid"));
        PCPU_SET(vcpu_id, (regs[0] & XEN_HVM_CPUID_VCPU_ID_PRESENT) ?
            regs[1] : PCPU_GET(acpi_id));

        if (xen_evtchn_needs_ack && !IS_BSP()) {
                /*
                 * Setup the per-vpcu event channel upcall vector. This is only
                 * required when using the new HVMOP_set_evtchn_upcall_vector
                 * hypercall, which allows using a different vector for each
                 * vCPU. Note that FreeBSD uses the same vector for all vCPUs
                 * because it's not dynamically allocated.
                 */
                rc = set_percpu_callback(PCPU_GET(vcpu_id));
                if (rc != 0)
                        panic("Event channel upcall vector setup failed: %d",
                            rc);
        }

        xen_setup_vcpu_info();
}
SYSINIT(xen_hvm_cpu_init, SI_SUB_INTR, SI_ORDER_FIRST, xen_hvm_cpu_init, NULL);

bool
xen_has_iommu_maps(void)
{
        uint32_t regs[4];

        KASSERT(hv_base != 0, ("Invalid base Xen CPUID leaf"));
        cpuid_count(hv_base + 4, 0, regs);

        return (regs[0] & XEN_HVM_CPUID_IOMMU_MAPPINGS);
}

int
xen_arch_init_physmem(device_t dev, struct rman *mem)
{
        static struct bios_smap smap[128];
        struct xen_memory_map memmap = {
                .nr_entries = nitems(smap),
        };
        unsigned int i;
        int error;

        set_xen_guest_handle(memmap.buffer, smap);
        error = HYPERVISOR_memory_op(XENMEM_memory_map, &memmap);
        if (error != 0)
                return (0);

        /*
         * Fill with UNUSABLE regions, as it's always fine to use those for
         * foreign mappings, they will never be populated.
         */
        for (i = 0; i < memmap.nr_entries; i++) {
                const vm_paddr_t max_phys = cpu_getmaxphyaddr();
                vm_paddr_t start, end;

                if (smap[i].type != SMAP_TYPE_ACPI_ERROR)
                        continue;

                start = round_page(smap[i].base);
                /* In 32bit mode we possibly need to truncate the addresses. */
                end = MIN(trunc_page(smap[i].base + smap[i].length) - 1,
                    max_phys);

                if (start >= end)
                        continue;

                if (bootverbose != 0)
                        device_printf(dev,
                            "scratch mapping region @ [%016jx, %016jx]\n",
                            start, end);

                error = rman_manage_region(mem, start, end);
                if (error != 0)
                        device_printf(dev,
                            "unable to add scratch region [%016jx, %016jx]: %d\n",
                            start, end, error);
        }

        return (0);
}