// SPDX-License-Identifier: GPL-2.0
/*
 * CR4 and CPUID sync test
 *
 * Copyright 2018, Red Hat, Inc. and/or its affiliates.
 *
 * Author:
 *   Wei Huang <wei@redhat.com>
 */

#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>

#include "test_util.h"

#include "kvm_util.h"
#include "processor.h"

#define MAGIC_HYPERCALL_PORT    0x80

static void guest_code(void)
{
        u32 regs[4] = {
                [KVM_CPUID_EAX] = X86_FEATURE_OSXSAVE.function,
                [KVM_CPUID_ECX] = X86_FEATURE_OSXSAVE.index,
        };

        /* CR4.OSXSAVE should be enabled by default (for selftests vCPUs). */
        GUEST_ASSERT(get_cr4() & X86_CR4_OSXSAVE);

        /* verify CR4.OSXSAVE == CPUID.OSXSAVE */
        GUEST_ASSERT(this_cpu_has(X86_FEATURE_OSXSAVE));

        /*
         * Notify hypervisor to clear CR4.0SXSAVE, do CPUID and save output,
         * and then restore CR4.  Do this all in  assembly to ensure no AVX
         * instructions are executed while OSXSAVE=0.
         */
        asm volatile (
                "out %%al, $" __stringify(MAGIC_HYPERCALL_PORT) "\n\t"
                "cpuid\n\t"
                "mov %%rdi, %%cr4\n\t"
                : "+a" (regs[KVM_CPUID_EAX]),
                  "=b" (regs[KVM_CPUID_EBX]),
                  "+c" (regs[KVM_CPUID_ECX]),
                  "=d" (regs[KVM_CPUID_EDX])
                : "D" (get_cr4())
        );

        /* Verify KVM cleared OSXSAVE in CPUID when it was cleared in CR4. */
        GUEST_ASSERT(!(regs[X86_FEATURE_OSXSAVE.reg] & BIT(X86_FEATURE_OSXSAVE.bit)));

        /* Verify restoring CR4 also restored OSXSAVE in CPUID. */
        GUEST_ASSERT(this_cpu_has(X86_FEATURE_OSXSAVE));

        GUEST_DONE();
}

int main(int argc, char *argv[])
{
        struct kvm_vcpu *vcpu;
        struct kvm_vm *vm;
        struct kvm_sregs sregs;
        struct ucall uc;

        TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_XSAVE));

        vm = vm_create_with_one_vcpu(&vcpu, guest_code);

        while (1) {
                vcpu_run(vcpu);
                TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);

                if (vcpu->run->io.port == MAGIC_HYPERCALL_PORT &&
                    vcpu->run->io.direction == KVM_EXIT_IO_OUT) {
                        /* emulate hypervisor clearing CR4.OSXSAVE */
                        vcpu_sregs_get(vcpu, &sregs);
                        sregs.cr4 &= ~X86_CR4_OSXSAVE;
                        vcpu_sregs_set(vcpu, &sregs);
                        continue;
                }

                switch (get_ucall(vcpu, &uc)) {
                case UCALL_ABORT:
                        REPORT_GUEST_ASSERT(uc);
                        break;
                case UCALL_DONE:
                        goto done;
                default:
                        TEST_FAIL("Unknown ucall %lu", uc.cmd);
                }
        }

done:
        kvm_vm_free(vm);
        return 0;
}