xref: /linux/tools/testing/selftests/kvm/x86/smm_test.c (revision 67f8bc848ee31831336bd478e57d2f993551902e)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2018, Red Hat, Inc.
4  *
5  * Tests for SMM.
6  */
7 #include <fcntl.h>
8 #include <stdio.h>
9 #include <stdlib.h>
10 #include <stdint.h>
11 #include <string.h>
12 #include <sys/ioctl.h>
13 
14 #include "test_util.h"
15 
16 #include "kvm_util.h"
17 #include "smm.h"
18 
19 #include "vmx.h"
20 #include "svm_util.h"
21 
22 #define SMRAM_GPA 0x1000000
23 #define SMRAM_STAGE 0xfe
24 
25 #define SYNC_PORT 0xe
26 #define DONE 0xff
27 
28 /*
29  * This is compiled as normal 64-bit code, however, SMI handler is executed
30  * in real-address mode. To stay simple we're limiting ourselves to a mode
31  * independent subset of asm here.
32  * SMI handler always report back fixed stage SMRAM_STAGE.
33  */
34 u8 smi_handler[] = {
35 	0xb0, SMRAM_STAGE,    /* mov $SMRAM_STAGE, %al */
36 	0xe4, SYNC_PORT,      /* in $SYNC_PORT, %al */
37 	0x0f, 0xaa,           /* rsm */
38 };
39 
40 static inline void sync_with_host(u64 phase)
41 {
42 	asm volatile("in $" __stringify(SYNC_PORT)", %%al \n"
43 		     : "+a" (phase));
44 }
45 
46 static void self_smi(void)
47 {
48 	x2apic_write_reg(APIC_ICR,
49 			 APIC_DEST_SELF | APIC_INT_ASSERT | APIC_DM_SMI);
50 }
51 
52 static void l2_guest_code(void)
53 {
54 	sync_with_host(8);
55 
56 	sync_with_host(10);
57 
58 	vmcall();
59 }
60 
61 static void guest_code(void *arg)
62 {
63 	u64 apicbase = rdmsr(MSR_IA32_APICBASE);
64 	struct svm_test_data *svm = arg;
65 	struct vmx_pages *vmx_pages = arg;
66 
67 	sync_with_host(1);
68 
69 	wrmsr(MSR_IA32_APICBASE, apicbase | X2APIC_ENABLE);
70 
71 	sync_with_host(2);
72 
73 	self_smi();
74 
75 	sync_with_host(4);
76 
77 	if (arg) {
78 		if (this_cpu_has(X86_FEATURE_SVM)) {
79 			generic_svm_setup(svm, l2_guest_code);
80 		} else {
81 			GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
82 			GUEST_ASSERT(load_vmcs(vmx_pages));
83 			prepare_vmcs(vmx_pages, l2_guest_code);
84 		}
85 
86 		sync_with_host(5);
87 
88 		self_smi();
89 
90 		sync_with_host(7);
91 
92 		if (this_cpu_has(X86_FEATURE_SVM)) {
93 			run_guest(svm->vmcb, svm->vmcb_gpa);
94 			run_guest(svm->vmcb, svm->vmcb_gpa);
95 		} else {
96 			vmlaunch();
97 			vmresume();
98 		}
99 
100 		/* Stages 8-11 are eaten by SMM (SMRAM_STAGE reported instead) */
101 		sync_with_host(12);
102 	}
103 
104 	sync_with_host(DONE);
105 }
106 
107 int main(int argc, char *argv[])
108 {
109 	gva_t nested_gva = 0;
110 
111 	struct kvm_vcpu *vcpu;
112 	struct kvm_regs regs;
113 	struct kvm_vm *vm;
114 	struct kvm_x86_state *state;
115 	int stage, stage_reported;
116 
117 	TEST_REQUIRE(kvm_has_cap(KVM_CAP_X86_SMM));
118 
119 	/* Create VM */
120 	vm = vm_create_with_one_vcpu(&vcpu, guest_code);
121 
122 	setup_smram(vm, vcpu, SMRAM_GPA, smi_handler, sizeof(smi_handler));
123 
124 	if (kvm_has_cap(KVM_CAP_NESTED_STATE)) {
125 		if (kvm_cpu_has(X86_FEATURE_SVM))
126 			vcpu_alloc_svm(vm, &nested_gva);
127 		else if (kvm_cpu_has(X86_FEATURE_VMX))
128 			vcpu_alloc_vmx(vm, &nested_gva);
129 	}
130 
131 	if (!nested_gva)
132 		pr_info("will skip SMM test with VMX enabled\n");
133 
134 	vcpu_args_set(vcpu, 1, nested_gva);
135 
136 	for (stage = 1;; stage++) {
137 		vcpu_run(vcpu);
138 		TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
139 
140 		memset(&regs, 0, sizeof(regs));
141 		vcpu_regs_get(vcpu, &regs);
142 
143 		stage_reported = regs.rax & 0xff;
144 
145 		if (stage_reported == DONE)
146 			goto done;
147 
148 		TEST_ASSERT(stage_reported == stage ||
149 			    stage_reported == SMRAM_STAGE,
150 			    "Unexpected stage: #%x, got %x",
151 			    stage, stage_reported);
152 
153 		/*
154 		 * Enter SMM during L2 execution and check that we correctly
155 		 * return from it. Do not perform save/restore while in SMM yet.
156 		 */
157 		if (stage == 8) {
158 			inject_smi(vcpu);
159 			continue;
160 		}
161 
162 		/*
163 		 * Perform save/restore while the guest is in SMM triggered
164 		 * during L2 execution.
165 		 */
166 		if (stage == 10)
167 			inject_smi(vcpu);
168 
169 		state = vcpu_save_state(vcpu);
170 		kvm_vm_release(vm);
171 
172 		vcpu = vm_recreate_with_one_vcpu(vm);
173 		vcpu_load_state(vcpu, state);
174 		kvm_x86_state_cleanup(state);
175 	}
176 
177 done:
178 	kvm_vm_free(vm);
179 }
180