1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2019, Google LLC.
4 *
5 * Tests for the IA32_XSS MSR.
6 */
7
8#define _GNU_SOURCE /* for program_invocation_short_name */
9#include <sys/ioctl.h>
10
11#include "test_util.h"
12#include "kvm_util.h"
13#include "vmx.h"
14
15#define MSR_BITS      64
16
17int main(int argc, char *argv[])
18{
19	bool xss_in_msr_list;
20	struct kvm_vm *vm;
21	struct kvm_vcpu *vcpu;
22	uint64_t xss_val;
23	int i, r;
24
25	/* Create VM */
26	vm = vm_create_with_one_vcpu(&vcpu, NULL);
27
28	TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_XSAVES));
29
30	xss_val = vcpu_get_msr(vcpu, MSR_IA32_XSS);
31	TEST_ASSERT(xss_val == 0,
32		    "MSR_IA32_XSS should be initialized to zero");
33
34	vcpu_set_msr(vcpu, MSR_IA32_XSS, xss_val);
35
36	/*
37	 * At present, KVM only supports a guest IA32_XSS value of 0. Verify
38	 * that trying to set the guest IA32_XSS to an unsupported value fails.
39	 * Also, in the future when a non-zero value succeeds check that
40	 * IA32_XSS is in the list of MSRs to save/restore.
41	 */
42	xss_in_msr_list = kvm_msr_is_in_save_restore_list(MSR_IA32_XSS);
43	for (i = 0; i < MSR_BITS; ++i) {
44		r = _vcpu_set_msr(vcpu, MSR_IA32_XSS, 1ull << i);
45
46		/*
47		 * Setting a list of MSRs returns the entry that "faulted", or
48		 * the last entry +1 if all MSRs were successfully written.
49		 */
50		TEST_ASSERT(!r || r == 1, KVM_IOCTL_ERROR(KVM_SET_MSRS, r));
51		TEST_ASSERT(r != 1 || xss_in_msr_list,
52			    "IA32_XSS was able to be set, but was not in save/restore list");
53	}
54
55	kvm_vm_free(vm);
56}
57