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

[Liam Merwick]

On 03/11/2022 14:28, Maxim Levitsky wrote:
> 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@xxxxxxxxxx>


Reviewed-by: Liam Merwick <liam.merwick@xxxxxxxxxx>


> > ---
> >   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);
> > +}