linux-kernel - Re: [PATCH v2 2/2] selftests: KVM: SVM: Add vmcall test

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Message-ID: <875zgoovhx.fsf@vitty.brq.redhat.com>
Date:   Mon, 03 Feb 2020 10:44:42 +0100
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     Eric Auger <eric.auger@...hat.com>
Cc:     thuth@...hat.com, drjones@...hat.com, wei.huang2@....com,
        eric.auger.pro@...il.com, eric.auger@...hat.com,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        pbonzini@...hat.com
Subject: Re: [PATCH v2 2/2] selftests: KVM: SVM: Add vmcall test

Eric Auger <eric.auger@...hat.com> writes:

> L2 guest calls vmcall and L1 checks the exit status does
> correspond.
>
> Signed-off-by: Eric Auger <eric.auger@...hat.com>
> ---
>  tools/testing/selftests/kvm/Makefile          |  1 +
>  .../selftests/kvm/x86_64/svm_vmcall_test.c    | 86 +++++++++++++++++++
>  2 files changed, 87 insertions(+)
>  create mode 100644 tools/testing/selftests/kvm/x86_64/svm_vmcall_test.c
>
> diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
> index 2e770f554cae..b529d3b42c02 100644
> --- a/tools/testing/selftests/kvm/Makefile
> +++ b/tools/testing/selftests/kvm/Makefile
> @@ -26,6 +26,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/vmx_dirty_log_test
>  TEST_GEN_PROGS_x86_64 += x86_64/vmx_set_nested_state_test
>  TEST_GEN_PROGS_x86_64 += x86_64/vmx_tsc_adjust_test
>  TEST_GEN_PROGS_x86_64 += x86_64/xss_msr_test
> +TEST_GEN_PROGS_x86_64 += x86_64/svm_vmcall_test
>  TEST_GEN_PROGS_x86_64 += clear_dirty_log_test
>  TEST_GEN_PROGS_x86_64 += dirty_log_test
>  TEST_GEN_PROGS_x86_64 += kvm_create_max_vcpus
> diff --git a/tools/testing/selftests/kvm/x86_64/svm_vmcall_test.c b/tools/testing/selftests/kvm/x86_64/svm_vmcall_test.c
> new file mode 100644
> index 000000000000..75e66f3bbbc0
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/x86_64/svm_vmcall_test.c
> @@ -0,0 +1,86 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * svm_vmcall_test
> + *
> + * Copyright (C) 2020, Red Hat, Inc.
> + *
> + * Nested SVM testing: VMCALL
> + */
> +
> +#include "test_util.h"
> +#include "kvm_util.h"
> +#include "processor.h"
> +#include "svm.h"
> +
> +#include <string.h>
> +#include <sys/ioctl.h>
> +
> +#include "kselftest.h"
> +#include <linux/kernel.h>
> +
> +#define VCPU_ID		5
> +
> +/* The virtual machine object. */

I'm not sure this comment is any helpful, the virus is probably
spreading from vmx_close_while_nested_test.c/vmx_tsc_adjust_test.c :-)

> +static struct kvm_vm *vm;
> +
> +static inline void l2_vmcall(struct svm_test_data *svm)
> +{
> +	__asm__ __volatile__("vmcall");
> +}
> +
> +static void l1_guest_code(struct svm_test_data *svm)
> +{
> +	#define L2_GUEST_STACK_SIZE 64
> +	unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
> +	struct vmcb *vmcb = svm->vmcb;
> +
> +	/* Prepare for L2 execution. */
> +	generic_svm_setup(svm, l2_vmcall,
> +			  &l2_guest_stack[L2_GUEST_STACK_SIZE]);
> +
> +	run_guest(vmcb, svm->vmcb_gpa);
> +
> +	GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
> +	GUEST_DONE();
> +}
> +
> +int main(int argc, char *argv[])
> +{
> +	vm_vaddr_t svm_gva;
> +
> +	nested_svm_check_supported();
> +
> +	vm = vm_create_default(VCPU_ID, 0, (void *) l1_guest_code);
> +	vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
> +
> +	vcpu_alloc_svm(vm, &svm_gva);
> +	vcpu_args_set(vm, VCPU_ID, 1, svm_gva);
> +
> +	for (;;) {
> +		volatile struct kvm_run *run = vcpu_state(vm, VCPU_ID);
> +		struct ucall uc;
> +
> +		vcpu_run(vm, VCPU_ID);
> +		TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
> +			    "Got exit_reason other than KVM_EXIT_IO: %u (%s)\n",
> +			    run->exit_reason,
> +			    exit_reason_str(run->exit_reason));
> +
> +		switch (get_ucall(vm, VCPU_ID, &uc)) {
> +		case UCALL_ABORT:
> +			TEST_ASSERT(false, "%s",
> +				    (const char *)uc.args[0]);
> +			/* NOT REACHED */
> +		case UCALL_SYNC:
> +			break;
> +		case UCALL_DONE:
> +			goto done;
> +		default:
> +			TEST_ASSERT(false,
> +				    "Unknown ucall 0x%x.", uc.cmd);
> +		}
> +	}
> +done:
> +	kvm_vm_free(vm);
> +	return 0;
> +}

Reviewed-by: Vitaly Kuznetsov <vkuznets@...hat.com>

Thanks!

-- 
Vitaly