// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2022, Red Hat, Inc.
 *
 * Tests for Hyper-V extensions to SVM.
 */
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <linux/bitmap.h>

#include "test_util.h"

#include "kvm_util.h"
#include "processor.h"
#include "svm_util.h"
#include "hyperv.h"

#define L2_GUEST_STACK_SIZE 256

/* Exit to L1 from L2 with RDMSR instruction */
static inline void rdmsr_from_l2(uint32_t msr)
{
        /* Currently, L1 doesn't preserve GPRs during vmexits. */
        __asm__ __volatile__ ("rdmsr" : : "c"(msr) :
                              "rax", "rbx", "rdx", "rsi", "rdi", "r8", "r9",
                              "r10", "r11", "r12", "r13", "r14", "r15");
}

void l2_guest_code(void)
{
        u64 unused;

        GUEST_SYNC(3);
        /* Exit to L1 */
        vmmcall();

        /* MSR-Bitmap tests */
        rdmsr_from_l2(MSR_FS_BASE); /* intercepted */
        rdmsr_from_l2(MSR_FS_BASE); /* intercepted */
        rdmsr_from_l2(MSR_GS_BASE); /* not intercepted */
        vmmcall();
        rdmsr_from_l2(MSR_GS_BASE); /* intercepted */

        GUEST_SYNC(5);

        /* L2 TLB flush tests */
        hyperv_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE |
                         HV_HYPERCALL_FAST_BIT, 0x0,
                         HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES |
                         HV_FLUSH_ALL_PROCESSORS);
        rdmsr_from_l2(MSR_FS_BASE);
        /*
         * Note: hypercall status (RAX) is not preserved correctly by L1 after
         * synthetic vmexit, use unchecked version.
         */
        __hyperv_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE |
                           HV_HYPERCALL_FAST_BIT, 0x0,
                           HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES |
                           HV_FLUSH_ALL_PROCESSORS, &unused);

        /* Done, exit to L1 and never come back.  */
        vmmcall();
}

static void __attribute__((__flatten__)) guest_code(struct svm_test_data *svm,
                                                    struct hyperv_test_pages *hv_pages,
                                                    vm_vaddr_t pgs_gpa)
{
        unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
        struct vmcb *vmcb = svm->vmcb;
        struct hv_vmcb_enlightenments *hve = &vmcb->control.hv_enlightenments;

        GUEST_SYNC(1);

        wrmsr(HV_X64_MSR_GUEST_OS_ID, HYPERV_LINUX_OS_ID);
        wrmsr(HV_X64_MSR_HYPERCALL, pgs_gpa);
        enable_vp_assist(hv_pages->vp_assist_gpa, hv_pages->vp_assist);

        GUEST_ASSERT(svm->vmcb_gpa);
        /* Prepare for L2 execution. */
        generic_svm_setup(svm, l2_guest_code,
                          &l2_guest_stack[L2_GUEST_STACK_SIZE]);

        /* L2 TLB flush setup */
        hve->partition_assist_page = hv_pages->partition_assist_gpa;
        hve->hv_enlightenments_control.nested_flush_hypercall = 1;
        hve->hv_vm_id = 1;
        hve->hv_vp_id = 1;
        current_vp_assist->nested_control.features.directhypercall = 1;
        *(u32 *)(hv_pages->partition_assist) = 0;

        GUEST_SYNC(2);
        run_guest(vmcb, svm->vmcb_gpa);
        GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
        GUEST_SYNC(4);
        vmcb->save.rip += 3;

        /* Intercept RDMSR 0xc0000100 */
        vmcb->control.intercept |= 1ULL << INTERCEPT_MSR_PROT;
        __set_bit(2 * (MSR_FS_BASE & 0x1fff), svm->msr + 0x800);
        run_guest(vmcb, svm->vmcb_gpa);
        GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_MSR);
        vmcb->save.rip += 2; /* rdmsr */

        /* Enable enlightened MSR bitmap */
        hve->hv_enlightenments_control.msr_bitmap = 1;
        run_guest(vmcb, svm->vmcb_gpa);
        GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_MSR);
        vmcb->save.rip += 2; /* rdmsr */

        /* Intercept RDMSR 0xc0000101 without telling KVM about it */
        __set_bit(2 * (MSR_GS_BASE & 0x1fff), svm->msr + 0x800);
        /* Make sure HV_VMX_ENLIGHTENED_CLEAN_FIELD_MSR_BITMAP is set */
        vmcb->control.clean |= HV_VMCB_NESTED_ENLIGHTENMENTS;
        run_guest(vmcb, svm->vmcb_gpa);
        /* Make sure we don't see SVM_EXIT_MSR here so eMSR bitmap works */
        GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
        vmcb->save.rip += 3; /* vmcall */

        /* Now tell KVM we've changed MSR-Bitmap */
        vmcb->control.clean &= ~HV_VMCB_NESTED_ENLIGHTENMENTS;
        run_guest(vmcb, svm->vmcb_gpa);
        GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_MSR);
        vmcb->save.rip += 2; /* rdmsr */


        /*
         * L2 TLB flush test. First VMCALL should be handled directly by L0,
         * no VMCALL exit expected.
         */
        run_guest(vmcb, svm->vmcb_gpa);
        GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_MSR);
        vmcb->save.rip += 2; /* rdmsr */
        /* Enable synthetic vmexit */
        *(u32 *)(hv_pages->partition_assist) = 1;
        run_guest(vmcb, svm->vmcb_gpa);
        GUEST_ASSERT(vmcb->control.exit_code == HV_SVM_EXITCODE_ENL);
        GUEST_ASSERT(vmcb->control.exit_info_1 == HV_SVM_ENL_EXITCODE_TRAP_AFTER_FLUSH);

        run_guest(vmcb, svm->vmcb_gpa);
        GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
        GUEST_SYNC(6);

        GUEST_DONE();
}

int main(int argc, char *argv[])
{
        vm_vaddr_t nested_gva = 0, hv_pages_gva = 0;
        vm_vaddr_t hcall_page;
        struct kvm_vcpu *vcpu;
        struct kvm_vm *vm;
        struct ucall uc;
        int stage;

        TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_SVM));
        TEST_REQUIRE(kvm_hv_cpu_has(HV_X64_NESTED_DIRECT_FLUSH));

        /* Create VM */
        vm = vm_create_with_one_vcpu(&vcpu, guest_code);
        vcpu_set_hv_cpuid(vcpu);
        vcpu_alloc_svm(vm, &nested_gva);
        vcpu_alloc_hyperv_test_pages(vm, &hv_pages_gva);

        hcall_page = vm_vaddr_alloc_pages(vm, 1);
        memset(addr_gva2hva(vm, hcall_page), 0x0,  getpagesize());

        vcpu_args_set(vcpu, 3, nested_gva, hv_pages_gva, addr_gva2gpa(vm, hcall_page));
        vcpu_set_msr(vcpu, HV_X64_MSR_VP_INDEX, vcpu->id);

        for (stage = 1;; stage++) {
                vcpu_run(vcpu);
                TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);

                switch (get_ucall(vcpu, &uc)) {
                case UCALL_ABORT:
                        REPORT_GUEST_ASSERT(uc);
                        /* NOT REACHED */
                case UCALL_SYNC:
                        break;
                case UCALL_DONE:
                        goto done;
                default:
                        TEST_FAIL("Unknown ucall %lu", uc.cmd);
                }

                /* UCALL_SYNC is handled here.  */
                TEST_ASSERT(!strcmp((const char *)uc.args[0], "hello") &&
                            uc.args[1] == stage, "Stage %d: Unexpected register values vmexit, got %lx",
                            stage, (ulong)uc.args[1]);

        }

done:
        kvm_vm_free(vm);
}