1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * KVM_GET/SET_* tests
4  *
5  * Copyright (C) 2022, Red Hat, Inc.
6  *
7  * Tests for Hyper-V extensions to SVM.
8  */
9 #define _GNU_SOURCE /* for program_invocation_short_name */
10 #include <fcntl.h>
11 #include <stdio.h>
12 #include <stdlib.h>
13 #include <string.h>
14 #include <sys/ioctl.h>
15 #include <linux/bitmap.h>
16 
17 #include "test_util.h"
18 
19 #include "kvm_util.h"
20 #include "processor.h"
21 #include "svm_util.h"
22 #include "hyperv.h"
23 
24 #define L2_GUEST_STACK_SIZE 256
25 
26 /* Exit to L1 from L2 with RDMSR instruction */
27 static inline void rdmsr_from_l2(uint32_t msr)
28 {
29 	/* Currently, L1 doesn't preserve GPRs during vmexits. */
30 	__asm__ __volatile__ ("rdmsr" : : "c"(msr) :
31 			      "rax", "rbx", "rdx", "rsi", "rdi", "r8", "r9",
32 			      "r10", "r11", "r12", "r13", "r14", "r15");
33 }
34 
35 void l2_guest_code(void)
36 {
37 	u64 unused;
38 
39 	GUEST_SYNC(3);
40 	/* Exit to L1 */
41 	vmmcall();
42 
43 	/* MSR-Bitmap tests */
44 	rdmsr_from_l2(MSR_FS_BASE); /* intercepted */
45 	rdmsr_from_l2(MSR_FS_BASE); /* intercepted */
46 	rdmsr_from_l2(MSR_GS_BASE); /* not intercepted */
47 	vmmcall();
48 	rdmsr_from_l2(MSR_GS_BASE); /* intercepted */
49 
50 	GUEST_SYNC(5);
51 
52 	/* L2 TLB flush tests */
53 	hyperv_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE |
54 			 HV_HYPERCALL_FAST_BIT, 0x0,
55 			 HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES |
56 			 HV_FLUSH_ALL_PROCESSORS);
57 	rdmsr_from_l2(MSR_FS_BASE);
58 	/*
59 	 * Note: hypercall status (RAX) is not preserved correctly by L1 after
60 	 * synthetic vmexit, use unchecked version.
61 	 */
62 	__hyperv_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE |
63 			   HV_HYPERCALL_FAST_BIT, 0x0,
64 			   HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES |
65 			   HV_FLUSH_ALL_PROCESSORS, &unused);
66 
67 	/* Done, exit to L1 and never come back.  */
68 	vmmcall();
69 }
70 
71 static void __attribute__((__flatten__)) guest_code(struct svm_test_data *svm,
72 						    struct hyperv_test_pages *hv_pages,
73 						    vm_vaddr_t pgs_gpa)
74 {
75 	unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
76 	struct vmcb *vmcb = svm->vmcb;
77 	struct hv_vmcb_enlightenments *hve = &vmcb->control.hv_enlightenments;
78 
79 	GUEST_SYNC(1);
80 
81 	wrmsr(HV_X64_MSR_GUEST_OS_ID, HYPERV_LINUX_OS_ID);
82 	wrmsr(HV_X64_MSR_HYPERCALL, pgs_gpa);
83 	enable_vp_assist(hv_pages->vp_assist_gpa, hv_pages->vp_assist);
84 
85 	GUEST_ASSERT(svm->vmcb_gpa);
86 	/* Prepare for L2 execution. */
87 	generic_svm_setup(svm, l2_guest_code,
88 			  &l2_guest_stack[L2_GUEST_STACK_SIZE]);
89 
90 	/* L2 TLB flush setup */
91 	hve->partition_assist_page = hv_pages->partition_assist_gpa;
92 	hve->hv_enlightenments_control.nested_flush_hypercall = 1;
93 	hve->hv_vm_id = 1;
94 	hve->hv_vp_id = 1;
95 	current_vp_assist->nested_control.features.directhypercall = 1;
96 	*(u32 *)(hv_pages->partition_assist) = 0;
97 
98 	GUEST_SYNC(2);
99 	run_guest(vmcb, svm->vmcb_gpa);
100 	GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
101 	GUEST_SYNC(4);
102 	vmcb->save.rip += 3;
103 
104 	/* Intercept RDMSR 0xc0000100 */
105 	vmcb->control.intercept |= 1ULL << INTERCEPT_MSR_PROT;
106 	__set_bit(2 * (MSR_FS_BASE & 0x1fff), svm->msr + 0x800);
107 	run_guest(vmcb, svm->vmcb_gpa);
108 	GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_MSR);
109 	vmcb->save.rip += 2; /* rdmsr */
110 
111 	/* Enable enlightened MSR bitmap */
112 	hve->hv_enlightenments_control.msr_bitmap = 1;
113 	run_guest(vmcb, svm->vmcb_gpa);
114 	GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_MSR);
115 	vmcb->save.rip += 2; /* rdmsr */
116 
117 	/* Intercept RDMSR 0xc0000101 without telling KVM about it */
118 	__set_bit(2 * (MSR_GS_BASE & 0x1fff), svm->msr + 0x800);
119 	/* Make sure HV_VMX_ENLIGHTENED_CLEAN_FIELD_MSR_BITMAP is set */
120 	vmcb->control.clean |= HV_VMCB_NESTED_ENLIGHTENMENTS;
121 	run_guest(vmcb, svm->vmcb_gpa);
122 	/* Make sure we don't see SVM_EXIT_MSR here so eMSR bitmap works */
123 	GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
124 	vmcb->save.rip += 3; /* vmcall */
125 
126 	/* Now tell KVM we've changed MSR-Bitmap */
127 	vmcb->control.clean &= ~HV_VMCB_NESTED_ENLIGHTENMENTS;
128 	run_guest(vmcb, svm->vmcb_gpa);
129 	GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_MSR);
130 	vmcb->save.rip += 2; /* rdmsr */
131 
132 
133 	/*
134 	 * L2 TLB flush test. First VMCALL should be handled directly by L0,
135 	 * no VMCALL exit expected.
136 	 */
137 	run_guest(vmcb, svm->vmcb_gpa);
138 	GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_MSR);
139 	vmcb->save.rip += 2; /* rdmsr */
140 	/* Enable synthetic vmexit */
141 	*(u32 *)(hv_pages->partition_assist) = 1;
142 	run_guest(vmcb, svm->vmcb_gpa);
143 	GUEST_ASSERT(vmcb->control.exit_code == HV_SVM_EXITCODE_ENL);
144 	GUEST_ASSERT(vmcb->control.exit_info_1 == HV_SVM_ENL_EXITCODE_TRAP_AFTER_FLUSH);
145 
146 	run_guest(vmcb, svm->vmcb_gpa);
147 	GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
148 	GUEST_SYNC(6);
149 
150 	GUEST_DONE();
151 }
152 
153 int main(int argc, char *argv[])
154 {
155 	vm_vaddr_t nested_gva = 0, hv_pages_gva = 0;
156 	vm_vaddr_t hcall_page;
157 	struct kvm_vcpu *vcpu;
158 	struct kvm_vm *vm;
159 	struct kvm_run *run;
160 	struct ucall uc;
161 	int stage;
162 
163 	TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_SVM));
164 
165 	/* Create VM */
166 	vm = vm_create_with_one_vcpu(&vcpu, guest_code);
167 	vcpu_set_hv_cpuid(vcpu);
168 	run = vcpu->run;
169 	vcpu_alloc_svm(vm, &nested_gva);
170 	vcpu_alloc_hyperv_test_pages(vm, &hv_pages_gva);
171 
172 	hcall_page = vm_vaddr_alloc_pages(vm, 1);
173 	memset(addr_gva2hva(vm, hcall_page), 0x0,  getpagesize());
174 
175 	vcpu_args_set(vcpu, 3, nested_gva, hv_pages_gva, addr_gva2gpa(vm, hcall_page));
176 	vcpu_set_msr(vcpu, HV_X64_MSR_VP_INDEX, vcpu->id);
177 
178 	for (stage = 1;; stage++) {
179 		vcpu_run(vcpu);
180 		TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
181 			    "Stage %d: unexpected exit reason: %u (%s),\n",
182 			    stage, run->exit_reason,
183 			    exit_reason_str(run->exit_reason));
184 
185 		switch (get_ucall(vcpu, &uc)) {
186 		case UCALL_ABORT:
187 			REPORT_GUEST_ASSERT(uc);
188 			/* NOT REACHED */
189 		case UCALL_SYNC:
190 			break;
191 		case UCALL_DONE:
192 			goto done;
193 		default:
194 			TEST_FAIL("Unknown ucall %lu", uc.cmd);
195 		}
196 
197 		/* UCALL_SYNC is handled here.  */
198 		TEST_ASSERT(!strcmp((const char *)uc.args[0], "hello") &&
199 			    uc.args[1] == stage, "Stage %d: Unexpected register values vmexit, got %lx",
200 			    stage, (ulong)uc.args[1]);
201 
202 	}
203 
204 done:
205 	kvm_vm_free(vm);
206 }
207