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 VCPU_ID 0
13 #define ARBITRARY_IO_PORT 0x2000
14
15 static struct kvm_vm *vm;
16
l2_guest_code(void)17 static void l2_guest_code(void)
18 {
19 /*
20 * Generate an exit to L0 userspace, i.e. main(), via I/O to an
21 * arbitrary port.
22 */
23 asm volatile("inb %%dx, %%al"
24 : : [port] "d" (ARBITRARY_IO_PORT) : "rax");
25 }
26
l1_guest_code(struct vmx_pages * vmx_pages)27 static void l1_guest_code(struct vmx_pages *vmx_pages)
28 {
29 #define L2_GUEST_STACK_SIZE 64
30 unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
31
32 GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
33 GUEST_ASSERT(load_vmcs(vmx_pages));
34
35 /* Prepare the VMCS for L2 execution. */
36 prepare_vmcs(vmx_pages, l2_guest_code,
37 &l2_guest_stack[L2_GUEST_STACK_SIZE]);
38
39 /*
40 * L2 must be run without unrestricted guest, verify that the selftests
41 * library hasn't enabled it. Because KVM selftests jump directly to
42 * 64-bit mode, unrestricted guest support isn't required.
43 */
44 GUEST_ASSERT(!(vmreadz(CPU_BASED_VM_EXEC_CONTROL) & CPU_BASED_ACTIVATE_SECONDARY_CONTROLS) ||
45 !(vmreadz(SECONDARY_VM_EXEC_CONTROL) & SECONDARY_EXEC_UNRESTRICTED_GUEST));
46
47 GUEST_ASSERT(!vmlaunch());
48
49 /* L2 should triple fault after main() stuffs invalid guest state. */
50 GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_TRIPLE_FAULT);
51 GUEST_DONE();
52 }
53
main(int argc,char * argv[])54 int main(int argc, char *argv[])
55 {
56 vm_vaddr_t vmx_pages_gva;
57 struct kvm_sregs sregs;
58 struct kvm_run *run;
59 struct ucall uc;
60
61 nested_vmx_check_supported();
62
63 vm = vm_create_default(VCPU_ID, 0, (void *) 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(vm, VCPU_ID, 1, vmx_pages_gva);
68
69 vcpu_run(vm, VCPU_ID);
70
71 run = vcpu_state(vm, VCPU_ID);
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(run->exit_reason == KVM_EXIT_IO,
78 "Expected KVM_EXIT_IO, got: %u (%s)\n",
79 run->exit_reason, exit_reason_str(run->exit_reason));
80
81 TEST_ASSERT(run->io.port == ARBITRARY_IO_PORT,
82 "Expected IN from port %d from L2, got port %d",
83 ARBITRARY_IO_PORT, run->io.port);
84
85 /*
86 * Stuff invalid guest state for L2 by making TR unusuable. The next
87 * KVM_RUN should induce a TRIPLE_FAULT in L2 as KVM doesn't support
88 * emulating invalid guest state for L2.
89 */
90 memset(&sregs, 0, sizeof(sregs));
91 vcpu_sregs_get(vm, VCPU_ID, &sregs);
92 sregs.tr.unusable = 1;
93 vcpu_sregs_set(vm, VCPU_ID, &sregs);
94
95 vcpu_run(vm, VCPU_ID);
96
97 switch (get_ucall(vm, VCPU_ID, &uc)) {
98 case UCALL_DONE:
99 break;
100 case UCALL_ABORT:
101 TEST_FAIL("%s", (const char *)uc.args[0]);
102 default:
103 TEST_FAIL("Unexpected ucall: %lu", uc.cmd);
104 }
105 }
106