/*
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms of version
 * 1.0 of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source.  A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 */
/* This file is dual-licensed; see usr/src/contrib/bhyve/LICENSE */

/*
 * Copyright 2019 Joyent, Inc.
 * Copyright 2025 Oxide Computer Company
 */

#include <sys/vmm_gpt_impl.h>
#include <sys/debug.h>

#define EPT_R           (1 << 0)
#define EPT_W           (1 << 1)
#define EPT_X           (1 << 2)
#define EPT_RWX         (EPT_R | EPT_W | EPT_X)
#define EPT_LGPG        (1 << 7)
#define EPT_ACCESSED    (1 << 8)
#define EPT_DIRTY       (1 << 9)

#define EPT_PA_MASK     (0x000ffffffffff000ull)

#define EPT_MAX_LEVELS  4

#define EPTP_FLAG_ACCESSED_DIRTY        (1 << 6)

CTASSERT(EPT_R == PROT_READ);
CTASSERT(EPT_W == PROT_WRITE);
CTASSERT(EPT_X == PROT_EXEC);

static inline uint64_t
ept_attr_to_pat(uint8_t attr)
{
        uint64_t bits = attr & 0x7;
        return (bits << 3);
}

static uint64_t
ept_map_table(uint64_t pfn)
{
        const uint64_t paddr = pfn_to_pa(pfn) & EPT_PA_MASK;
        return (paddr | EPT_RWX);
}

static uint64_t
ept_map_page(uint64_t pfn, uint_t prot, uint8_t attr)
{
        const uint64_t paddr = pfn_to_pa(pfn) & EPT_PA_MASK;
        const uint64_t pat = ept_attr_to_pat(attr);
        const uint64_t rprot = prot & EPT_RWX;
        return (paddr | pat | rprot);
}

static bool
ept_pte_parse(uint64_t pte, pfn_t *pfnp, uint_t *protp)
{
        const uint_t prot = pte & EPT_RWX;

        if (prot == 0) {
                return (false);
        }

        if (pfnp != NULL) {
                *pfnp = (pte & PT_PADDR) >> PAGESHIFT;
        }
        if (protp != NULL) {
                *protp = prot;
        }
        return (true);
}

static uint64_t
ept_get_pmtp(pfn_t root_pfn, bool track_dirty)
{
        const uint64_t ad_flag = track_dirty ? EPTP_FLAG_ACCESSED_DIRTY : 0;
        return ((root_pfn << PAGESHIFT | ad_flag |
            (EPT_MAX_LEVELS - 1) << 3 | MTRR_TYPE_WB));
}

static bool
ept_hw_ad_supported(void)
{
        uint64_t ept_caps = rdmsr(MSR_IA32_VMX_EPT_VPID_CAP);
        return ((ept_caps & IA32_VMX_EPT_VPID_HW_AD) != 0);
}

const struct vmm_pte_impl ept_pte_impl = {
        .vpi_map_table          = ept_map_table,
        .vpi_map_page           = ept_map_page,
        .vpi_pte_parse          = ept_pte_parse,
        .vpi_bit_accessed       = EPT_ACCESSED,
        .vpi_bit_dirty          = EPT_DIRTY,

        .vpi_get_pmtp           = ept_get_pmtp,
        .vpi_hw_ad_supported    = ept_hw_ad_supported,
};