1 // SPDX-License-Identifier: GPL-2.0-only
2 #include "test_util.h"
3 #include "kvm_util.h"
4 #include "processor.h"
5 #include "vmx.h"
6 
7 #include <string.h>
8 #include <sys/ioctl.h>
9 
10 #include "kselftest.h"
11 
12 #define ARBITRARY_IO_PORT 0x2000
13 
14 static struct kvm_vm *vm;
15 
16 static void l2_guest_code(void)
17 {
18 	/*
19 	 * Generate an exit to L0 userspace, i.e. main(), via I/O to an
20 	 * arbitrary port.
21 	 */
22 	asm volatile("inb %%dx, %%al"
23 		     : : [port] "d" (ARBITRARY_IO_PORT) : "rax");
24 }
25 
26 static void l1_guest_code(struct vmx_pages *vmx_pages)
27 {
28 #define L2_GUEST_STACK_SIZE 64
29 	unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
30 
31 	GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
32 	GUEST_ASSERT(load_vmcs(vmx_pages));
33 
34 	/* Prepare the VMCS for L2 execution. */
35 	prepare_vmcs(vmx_pages, l2_guest_code,
36 		     &l2_guest_stack[L2_GUEST_STACK_SIZE]);
37 
38 	/*
39 	 * L2 must be run without unrestricted guest, verify that the selftests
40 	 * library hasn't enabled it.  Because KVM selftests jump directly to
41 	 * 64-bit mode, unrestricted guest support isn't required.
42 	 */
43 	GUEST_ASSERT(!(vmreadz(CPU_BASED_VM_EXEC_CONTROL) & CPU_BASED_ACTIVATE_SECONDARY_CONTROLS) ||
44 		     !(vmreadz(SECONDARY_VM_EXEC_CONTROL) & SECONDARY_EXEC_UNRESTRICTED_GUEST));
45 
46 	GUEST_ASSERT(!vmlaunch());
47 
48 	/* L2 should triple fault after main() stuffs invalid guest state. */
49 	GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_TRIPLE_FAULT);
50 	GUEST_DONE();
51 }
52 
53 int main(int argc, char *argv[])
54 {
55 	vm_vaddr_t vmx_pages_gva;
56 	struct kvm_sregs sregs;
57 	struct kvm_vcpu *vcpu;
58 	struct kvm_run *run;
59 	struct ucall uc;
60 
61 	TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_VMX));
62 
63 	vm = vm_create_with_one_vcpu(&vcpu, l1_guest_code);
64 
65 	/* Allocate VMX pages and shared descriptors (vmx_pages). */
66 	vcpu_alloc_vmx(vm, &vmx_pages_gva);
67 	vcpu_args_set(vcpu, 1, vmx_pages_gva);
68 
69 	vcpu_run(vcpu);
70 
71 	run = vcpu->run;
72 
73 	/*
74 	 * The first exit to L0 userspace should be an I/O access from L2.
75 	 * Running L1 should launch L2 without triggering an exit to userspace.
76 	 */
77 	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
78 
79 	TEST_ASSERT(run->io.port == ARBITRARY_IO_PORT,
80 		    "Expected IN from port %d from L2, got port %d",
81 		    ARBITRARY_IO_PORT, run->io.port);
82 
83 	/*
84 	 * Stuff invalid guest state for L2 by making TR unusuable.  The next
85 	 * KVM_RUN should induce a TRIPLE_FAULT in L2 as KVM doesn't support
86 	 * emulating invalid guest state for L2.
87 	 */
88 	memset(&sregs, 0, sizeof(sregs));
89 	vcpu_sregs_get(vcpu, &sregs);
90 	sregs.tr.unusable = 1;
91 	vcpu_sregs_set(vcpu, &sregs);
92 
93 	vcpu_run(vcpu);
94 
95 	switch (get_ucall(vcpu, &uc)) {
96 	case UCALL_DONE:
97 		break;
98 	case UCALL_ABORT:
99 		REPORT_GUEST_ASSERT(uc);
100 	default:
101 		TEST_FAIL("Unexpected ucall: %lu", uc.cmd);
102 	}
103 }
104