linux-kernel - Re: [PATCH v2 6/9] kvm: selftests: add svm nested shutdown test

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Message-ID: <2dccbbaa2d9e9aa7895fc03488c503c544aa0399.camel@redhat.com>
Date:   Thu, 03 Nov 2022 16:28:41 +0200
From:   Maxim Levitsky <mlevitsk@...hat.com>
To:     kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-kernel@...r.kernel.org,
        Chenyi Qiang <chenyi.qiang@...el.com>,
        Yang Zhong <yang.zhong@...el.com>, x86@...nel.org,
        Shuah Khan <shuah@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Colton Lewis <coltonlewis@...gle.com>,
        Borislav Petkov <bp@...en8.de>, Peter Xu <peterx@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Jim Mattson <jmattson@...gle.com>,
        linux-kselftest@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
        Wei Wang <wei.w.wang@...el.com>,
        David Matlack <dmatlack@...gle.com>
Subject: Re: [PATCH v2 6/9] kvm: selftests: add svm nested shutdown test

On Thu, 2022-11-03 at 16:13 +0200, Maxim Levitsky wrote:
> Add test that tests that on SVM if L1 doesn't intercept SHUTDOWN,
> then L2 crashes L1 and doesn't crash L2
I mean doesn't crash L0, sorry for typo.

Best regards,
	Maxim Levitsky
> 
> Signed-off-by: Maxim Levitsky <mlevitsk@...hat.com>
> ---
>  tools/testing/selftests/kvm/.gitignore        |  1 +
>  tools/testing/selftests/kvm/Makefile          |  1 +
>  .../kvm/x86_64/svm_nested_shutdown_test.c     | 67 +++++++++++++++++++
>  3 files changed, 69 insertions(+)
>  create mode 100644 tools/testing/selftests/kvm/x86_64/svm_nested_shutdown_test.c
> 
> diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
> index 2f0d705db9dba5..05d980fb083d17 100644
> --- a/tools/testing/selftests/kvm/.gitignore
> +++ b/tools/testing/selftests/kvm/.gitignore
> @@ -41,6 +41,7 @@
>  /x86_64/svm_vmcall_test
>  /x86_64/svm_int_ctl_test
>  /x86_64/svm_nested_soft_inject_test
> +/x86_64/svm_nested_shutdown_test
>  /x86_64/sync_regs_test
>  /x86_64/tsc_msrs_test
>  /x86_64/tsc_scaling_sync
> diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
> index 0172eb6cb6eee2..4a2caef2c9396f 100644
> --- a/tools/testing/selftests/kvm/Makefile
> +++ b/tools/testing/selftests/kvm/Makefile
> @@ -101,6 +101,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/state_test
>  TEST_GEN_PROGS_x86_64 += x86_64/vmx_preemption_timer_test
>  TEST_GEN_PROGS_x86_64 += x86_64/svm_vmcall_test
>  TEST_GEN_PROGS_x86_64 += x86_64/svm_int_ctl_test
> +TEST_GEN_PROGS_x86_64 += x86_64/svm_nested_shutdown_test
>  TEST_GEN_PROGS_x86_64 += x86_64/svm_nested_soft_inject_test
>  TEST_GEN_PROGS_x86_64 += x86_64/tsc_scaling_sync
>  TEST_GEN_PROGS_x86_64 += x86_64/sync_regs_test
> diff --git a/tools/testing/selftests/kvm/x86_64/svm_nested_shutdown_test.c b/tools/testing/selftests/kvm/x86_64/svm_nested_shutdown_test.c
> new file mode 100644
> index 00000000000000..e73fcdef47bbe9
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/x86_64/svm_nested_shutdown_test.c
> @@ -0,0 +1,67 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * svm_nested_shutdown_test
> + *
> + * Copyright (C) 2022, Red Hat, Inc.
> + *
> + * Nested SVM testing: test that unintercepted shutdown in L2 doesn't crash the host
> + */
> +
> +#include "test_util.h"
> +#include "kvm_util.h"
> +#include "processor.h"
> +#include "svm_util.h"
> +
> +static void l2_guest_code(struct svm_test_data *svm)
> +{
> +       __asm__ __volatile__("ud2");
> +}
> +
> +static void l1_guest_code(struct svm_test_data *svm, struct idt_entry *idt)
> +{
> +       #define L2_GUEST_STACK_SIZE 64
> +       unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
> +       struct vmcb *vmcb = svm->vmcb;
> +
> +       generic_svm_setup(svm, l2_guest_code,
> +                         &l2_guest_stack[L2_GUEST_STACK_SIZE]);
> +
> +       vmcb->control.intercept &= ~(BIT(INTERCEPT_SHUTDOWN));
> +
> +       idt[6].p   = 0; // #UD is intercepted but its injection will cause #NP
> +       idt[11].p  = 0; // #NP is not intercepted and will cause another
> +                       // #NP that will be converted to #DF
> +       idt[8].p   = 0; // #DF will cause #NP which will cause SHUTDOWN
> +
> +       run_guest(vmcb, svm->vmcb_gpa);
> +
> +       /* should not reach here */
> +       GUEST_ASSERT(0);
> +}
> +
> +int main(int argc, char *argv[])
> +{
> +       struct kvm_vcpu *vcpu;
> +       struct kvm_run *run;
> +       vm_vaddr_t svm_gva;
> +       struct kvm_vm *vm;
> +
> +       TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_SVM));
> +
> +       vm = vm_create_with_one_vcpu(&vcpu, l1_guest_code);
> +       vm_init_descriptor_tables(vm);
> +       vcpu_init_descriptor_tables(vcpu);
> +
> +       vcpu_alloc_svm(vm, &svm_gva);
> +
> +       vcpu_args_set(vcpu, 2, svm_gva, vm->idt);
> +       run = vcpu->run;
> +
> +       vcpu_run(vcpu);
> +       TEST_ASSERT(run->exit_reason == KVM_EXIT_SHUTDOWN,
> +                   "Got exit_reason other than KVM_EXIT_SHUTDOWN: %u (%s)\n",
> +                   run->exit_reason,
> +                   exit_reason_str(run->exit_reason));
> +
> +       kvm_vm_free(vm);
> +}