1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * CR4 and CPUID sync test
4  *
5  * Copyright 2018, Red Hat, Inc. and/or its affiliates.
6  *
7  * Author:
8  *   Wei Huang <wei@redhat.com>
9  */
10 
11 #include <fcntl.h>
12 #include <stdio.h>
13 #include <stdlib.h>
14 #include <string.h>
15 #include <sys/ioctl.h>
16 
17 #include "test_util.h"
18 
19 #include "kvm_util.h"
20 #include "processor.h"
21 
22 #define X86_FEATURE_XSAVE	(1<<26)
23 #define X86_FEATURE_OSXSAVE	(1<<27)
24 #define VCPU_ID			1
25 
26 static inline bool cr4_cpuid_is_sync(void)
27 {
28 	int func, subfunc;
29 	uint32_t eax, ebx, ecx, edx;
30 	uint64_t cr4;
31 
32 	func = 0x1;
33 	subfunc = 0x0;
34 	__asm__ __volatile__("cpuid"
35 			     : "=a"(eax), "=b"(ebx), "=c"(ecx), "=d"(edx)
36 			     : "a"(func), "c"(subfunc));
37 
38 	cr4 = get_cr4();
39 
40 	return (!!(ecx & X86_FEATURE_OSXSAVE)) == (!!(cr4 & X86_CR4_OSXSAVE));
41 }
42 
43 static void guest_code(void)
44 {
45 	uint64_t cr4;
46 
47 	/* turn on CR4.OSXSAVE */
48 	cr4 = get_cr4();
49 	cr4 |= X86_CR4_OSXSAVE;
50 	set_cr4(cr4);
51 
52 	/* verify CR4.OSXSAVE == CPUID.OSXSAVE */
53 	GUEST_ASSERT(cr4_cpuid_is_sync());
54 
55 	/* notify hypervisor to change CR4 */
56 	GUEST_SYNC(0);
57 
58 	/* check again */
59 	GUEST_ASSERT(cr4_cpuid_is_sync());
60 
61 	GUEST_DONE();
62 }
63 
64 int main(int argc, char *argv[])
65 {
66 	struct kvm_run *run;
67 	struct kvm_vm *vm;
68 	struct kvm_sregs sregs;
69 	struct kvm_cpuid_entry2 *entry;
70 	struct ucall uc;
71 	int rc;
72 
73 	entry = kvm_get_supported_cpuid_entry(1);
74 	if (!(entry->ecx & X86_FEATURE_XSAVE)) {
75 		print_skip("XSAVE feature not supported");
76 		return 0;
77 	}
78 
79 	/* Tell stdout not to buffer its content */
80 	setbuf(stdout, NULL);
81 
82 	/* Create VM */
83 	vm = vm_create_default(VCPU_ID, 0, guest_code);
84 	run = vcpu_state(vm, VCPU_ID);
85 
86 	while (1) {
87 		rc = _vcpu_run(vm, VCPU_ID);
88 
89 		TEST_ASSERT(rc == 0, "vcpu_run failed: %d\n", rc);
90 		TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
91 			    "Unexpected exit reason: %u (%s),\n",
92 			    run->exit_reason,
93 			    exit_reason_str(run->exit_reason));
94 
95 		switch (get_ucall(vm, VCPU_ID, &uc)) {
96 		case UCALL_SYNC:
97 			/* emulate hypervisor clearing CR4.OSXSAVE */
98 			vcpu_sregs_get(vm, VCPU_ID, &sregs);
99 			sregs.cr4 &= ~X86_CR4_OSXSAVE;
100 			vcpu_sregs_set(vm, VCPU_ID, &sregs);
101 			break;
102 		case UCALL_ABORT:
103 			TEST_FAIL("Guest CR4 bit (OSXSAVE) unsynchronized with CPUID bit.");
104 			break;
105 		case UCALL_DONE:
106 			goto done;
107 		default:
108 			TEST_FAIL("Unknown ucall %lu", uc.cmd);
109 		}
110 	}
111 
112 done:
113 	kvm_vm_free(vm);
114 	return 0;
115 }
116