xref: /linux/tools/testing/selftests/kvm/x86_64/xen_vmcall_test.c (revision f858cc9eed5b05cbe38d7ffd2787c21e3718eb7d)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * xen_vmcall_test
4  *
5  * Copyright © 2020 Amazon.com, Inc. or its affiliates.
6  *
7  * Userspace hypercall testing
8  */
9 
10 #include "test_util.h"
11 #include "kvm_util.h"
12 #include "processor.h"
13 #include "hyperv.h"
14 
15 #define HCALL_REGION_GPA	0xc0000000ULL
16 #define HCALL_REGION_SLOT	10
17 
18 #define INPUTVALUE 17
19 #define ARGVALUE(x) (0xdeadbeef5a5a0000UL + x)
20 #define RETVALUE 0xcafef00dfbfbffffUL
21 
22 #define XEN_HYPERCALL_MSR	0x40000200
23 #define HV_GUEST_OS_ID_MSR	0x40000000
24 #define HV_HYPERCALL_MSR	0x40000001
25 
26 #define HVCALL_SIGNAL_EVENT		0x005d
27 #define HV_STATUS_INVALID_ALIGNMENT	4
28 
29 static void guest_code(void)
30 {
31 	unsigned long rax = INPUTVALUE;
32 	unsigned long rdi = ARGVALUE(1);
33 	unsigned long rsi = ARGVALUE(2);
34 	unsigned long rdx = ARGVALUE(3);
35 	unsigned long rcx;
36 	register unsigned long r10 __asm__("r10") = ARGVALUE(4);
37 	register unsigned long r8 __asm__("r8") = ARGVALUE(5);
38 	register unsigned long r9 __asm__("r9") = ARGVALUE(6);
39 
40 	/* First a direct invocation of 'vmcall' */
41 	__asm__ __volatile__("vmcall" :
42 			     "=a"(rax) :
43 			     "a"(rax), "D"(rdi), "S"(rsi), "d"(rdx),
44 			     "r"(r10), "r"(r8), "r"(r9));
45 	GUEST_ASSERT(rax == RETVALUE);
46 
47 	/* Fill in the Xen hypercall page */
48 	__asm__ __volatile__("wrmsr" : : "c" (XEN_HYPERCALL_MSR),
49 			     "a" (HCALL_REGION_GPA & 0xffffffff),
50 			     "d" (HCALL_REGION_GPA >> 32));
51 
52 	/* Set Hyper-V Guest OS ID */
53 	__asm__ __volatile__("wrmsr" : : "c" (HV_GUEST_OS_ID_MSR),
54 			     "a" (0x5a), "d" (0));
55 
56 	/* Hyper-V hypercall page */
57 	u64 msrval = HCALL_REGION_GPA + PAGE_SIZE + 1;
58 	__asm__ __volatile__("wrmsr" : : "c" (HV_HYPERCALL_MSR),
59 			     "a" (msrval & 0xffffffff),
60 			     "d" (msrval >> 32));
61 
62 	/* Invoke a Xen hypercall */
63 	__asm__ __volatile__("call *%1" : "=a"(rax) :
64 			     "r"(HCALL_REGION_GPA + INPUTVALUE * 32),
65 			     "a"(rax), "D"(rdi), "S"(rsi), "d"(rdx),
66 			     "r"(r10), "r"(r8), "r"(r9));
67 	GUEST_ASSERT(rax == RETVALUE);
68 
69 	/* Invoke a Hyper-V hypercall */
70 	rax = 0;
71 	rcx = HVCALL_SIGNAL_EVENT;	/* code */
72 	rdx = 0x5a5a5a5a;		/* ingpa (badly aligned) */
73 	__asm__ __volatile__("call *%1" : "=a"(rax) :
74 			     "r"(HCALL_REGION_GPA + PAGE_SIZE),
75 			     "a"(rax), "c"(rcx), "d"(rdx),
76 			     "r"(r8));
77 	GUEST_ASSERT(rax == HV_STATUS_INVALID_ALIGNMENT);
78 
79 	GUEST_DONE();
80 }
81 
82 int main(int argc, char *argv[])
83 {
84 	unsigned int xen_caps;
85 	struct kvm_vcpu *vcpu;
86 	struct kvm_vm *vm;
87 
88 	xen_caps = kvm_check_cap(KVM_CAP_XEN_HVM);
89 	TEST_REQUIRE(xen_caps & KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL);
90 
91 	vm = vm_create_with_one_vcpu(&vcpu, guest_code);
92 	vcpu_set_hv_cpuid(vcpu);
93 
94 	struct kvm_xen_hvm_config hvmc = {
95 		.flags = KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL,
96 		.msr = XEN_HYPERCALL_MSR,
97 	};
98 	vm_ioctl(vm, KVM_XEN_HVM_CONFIG, &hvmc);
99 
100 	/* Map a region for the hypercall pages */
101 	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
102 				    HCALL_REGION_GPA, HCALL_REGION_SLOT, 2, 0);
103 	virt_map(vm, HCALL_REGION_GPA, HCALL_REGION_GPA, 2);
104 
105 	for (;;) {
106 		volatile struct kvm_run *run = vcpu->run;
107 		struct ucall uc;
108 
109 		vcpu_run(vcpu);
110 
111 		if (run->exit_reason == KVM_EXIT_XEN) {
112 			TEST_ASSERT_EQ(run->xen.type, KVM_EXIT_XEN_HCALL);
113 			TEST_ASSERT_EQ(run->xen.u.hcall.cpl, 0);
114 			TEST_ASSERT_EQ(run->xen.u.hcall.longmode, 1);
115 			TEST_ASSERT_EQ(run->xen.u.hcall.input, INPUTVALUE);
116 			TEST_ASSERT_EQ(run->xen.u.hcall.params[0], ARGVALUE(1));
117 			TEST_ASSERT_EQ(run->xen.u.hcall.params[1], ARGVALUE(2));
118 			TEST_ASSERT_EQ(run->xen.u.hcall.params[2], ARGVALUE(3));
119 			TEST_ASSERT_EQ(run->xen.u.hcall.params[3], ARGVALUE(4));
120 			TEST_ASSERT_EQ(run->xen.u.hcall.params[4], ARGVALUE(5));
121 			TEST_ASSERT_EQ(run->xen.u.hcall.params[5], ARGVALUE(6));
122 			run->xen.u.hcall.result = RETVALUE;
123 			continue;
124 		}
125 
126 		TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
127 
128 		switch (get_ucall(vcpu, &uc)) {
129 		case UCALL_ABORT:
130 			REPORT_GUEST_ASSERT(uc);
131 			/* NOT REACHED */
132 		case UCALL_SYNC:
133 			break;
134 		case UCALL_DONE:
135 			goto done;
136 		default:
137 			TEST_FAIL("Unknown ucall 0x%lx.", uc.cmd);
138 		}
139 	}
140 done:
141 	kvm_vm_free(vm);
142 	return 0;
143 }
144