// SPDX-License-Identifier: GPL-2.0-only
/*
 * Hyper-V specific functions.
 *
 * Copyright (C) 2021, Red Hat Inc.
 */
#include <stdint.h>
#include "processor.h"
#include "hyperv.h"

const struct kvm_cpuid2 *kvm_get_supported_hv_cpuid(void)
{
        static struct kvm_cpuid2 *cpuid;
        int kvm_fd;

        if (cpuid)
                return cpuid;

        cpuid = allocate_kvm_cpuid2(MAX_NR_CPUID_ENTRIES);
        kvm_fd = open_kvm_dev_path_or_exit();

        kvm_ioctl(kvm_fd, KVM_GET_SUPPORTED_HV_CPUID, cpuid);

        close(kvm_fd);
        return cpuid;
}

void vcpu_set_hv_cpuid(struct kvm_vcpu *vcpu)
{
        static struct kvm_cpuid2 *cpuid_full;
        const struct kvm_cpuid2 *cpuid_sys, *cpuid_hv;
        int i, nent = 0;

        if (!cpuid_full) {
                cpuid_sys = kvm_get_supported_cpuid();
                cpuid_hv = kvm_get_supported_hv_cpuid();

                cpuid_full = allocate_kvm_cpuid2(cpuid_sys->nent + cpuid_hv->nent);
                if (!cpuid_full) {
                        perror("malloc");
                        abort();
                }

                /* Need to skip KVM CPUID leaves 0x400000xx */
                for (i = 0; i < cpuid_sys->nent; i++) {
                        if (cpuid_sys->entries[i].function >= 0x40000000 &&
                            cpuid_sys->entries[i].function < 0x40000100)
                                continue;
                        cpuid_full->entries[nent] = cpuid_sys->entries[i];
                        nent++;
                }

                memcpy(&cpuid_full->entries[nent], cpuid_hv->entries,
                       cpuid_hv->nent * sizeof(struct kvm_cpuid_entry2));
                cpuid_full->nent = nent + cpuid_hv->nent;
        }

        vcpu_init_cpuid(vcpu, cpuid_full);
}

const struct kvm_cpuid2 *vcpu_get_supported_hv_cpuid(struct kvm_vcpu *vcpu)
{
        struct kvm_cpuid2 *cpuid = allocate_kvm_cpuid2(MAX_NR_CPUID_ENTRIES);

        vcpu_ioctl(vcpu, KVM_GET_SUPPORTED_HV_CPUID, cpuid);

        return cpuid;
}

bool kvm_hv_cpu_has(struct kvm_x86_cpu_feature feature)
{
        if (!kvm_has_cap(KVM_CAP_SYS_HYPERV_CPUID))
                return false;

        return kvm_cpuid_has(kvm_get_supported_hv_cpuid(), feature);
}

struct hyperv_test_pages *vcpu_alloc_hyperv_test_pages(struct kvm_vm *vm,
                                                       vm_vaddr_t *p_hv_pages_gva)
{
        vm_vaddr_t hv_pages_gva = vm_vaddr_alloc_page(vm);
        struct hyperv_test_pages *hv = addr_gva2hva(vm, hv_pages_gva);

        /* Setup of a region of guest memory for the VP Assist page. */
        hv->vp_assist = (void *)vm_vaddr_alloc_page(vm);
        hv->vp_assist_hva = addr_gva2hva(vm, (uintptr_t)hv->vp_assist);
        hv->vp_assist_gpa = addr_gva2gpa(vm, (uintptr_t)hv->vp_assist);

        /* Setup of a region of guest memory for the partition assist page. */
        hv->partition_assist = (void *)vm_vaddr_alloc_page(vm);
        hv->partition_assist_hva = addr_gva2hva(vm, (uintptr_t)hv->partition_assist);
        hv->partition_assist_gpa = addr_gva2gpa(vm, (uintptr_t)hv->partition_assist);

        /* Setup of a region of guest memory for the enlightened VMCS. */
        hv->enlightened_vmcs = (void *)vm_vaddr_alloc_page(vm);
        hv->enlightened_vmcs_hva = addr_gva2hva(vm, (uintptr_t)hv->enlightened_vmcs);
        hv->enlightened_vmcs_gpa = addr_gva2gpa(vm, (uintptr_t)hv->enlightened_vmcs);

        *p_hv_pages_gva = hv_pages_gva;
        return hv;
}

int enable_vp_assist(uint64_t vp_assist_pa, void *vp_assist)
{
        uint64_t val = (vp_assist_pa & HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_MASK) |
                HV_X64_MSR_VP_ASSIST_PAGE_ENABLE;

        wrmsr(HV_X64_MSR_VP_ASSIST_PAGE, val);

        current_vp_assist = vp_assist;

        return 0;
}