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