1 // SPDX-License-Identifier: GPL-2.0
2 #include <fcntl.h>
3 #include <stdio.h>
4 #include <stdlib.h>
5 #include <string.h>
6 #include <sys/ioctl.h>
7
8 #include "test_util.h"
9
10 #include "kvm_util.h"
11 #include "processor.h"
12
guest_ins_port80(uint8_t * buffer,unsigned int count)13 static void guest_ins_port80(uint8_t *buffer, unsigned int count)
14 {
15 unsigned long end;
16
17 if (count == 2)
18 end = (unsigned long)buffer + 1;
19 else
20 end = (unsigned long)buffer + 8192;
21
22 asm volatile("cld; rep; insb" : "+D"(buffer), "+c"(count) : "d"(0x80) : "memory");
23 GUEST_ASSERT_1(count == 0, count);
24 GUEST_ASSERT_2((unsigned long)buffer == end, buffer, end);
25 }
26
guest_code(void)27 static void guest_code(void)
28 {
29 uint8_t buffer[8192];
30 int i;
31
32 /*
33 * Special case tests. main() will adjust RCX 2 => 1 and 3 => 8192 to
34 * test that KVM doesn't explode when userspace modifies the "count" on
35 * a userspace I/O exit. KVM isn't required to play nice with the I/O
36 * itself as KVM doesn't support manipulating the count, it just needs
37 * to not explode or overflow a buffer.
38 */
39 guest_ins_port80(buffer, 2);
40 guest_ins_port80(buffer, 3);
41
42 /* Verify KVM fills the buffer correctly when not stuffing RCX. */
43 memset(buffer, 0, sizeof(buffer));
44 guest_ins_port80(buffer, 8192);
45 for (i = 0; i < 8192; i++)
46 GUEST_ASSERT_2(buffer[i] == 0xaa, i, buffer[i]);
47
48 GUEST_DONE();
49 }
50
main(int argc,char * argv[])51 int main(int argc, char *argv[])
52 {
53 struct kvm_vcpu *vcpu;
54 struct kvm_regs regs;
55 struct kvm_run *run;
56 struct kvm_vm *vm;
57 struct ucall uc;
58
59 /* Tell stdout not to buffer its content */
60 setbuf(stdout, NULL);
61
62 vm = vm_create_with_one_vcpu(&vcpu, guest_code);
63 run = vcpu->run;
64
65 memset(®s, 0, sizeof(regs));
66
67 while (1) {
68 vcpu_run(vcpu);
69
70 TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
71 "Unexpected exit reason: %u (%s),\n",
72 run->exit_reason,
73 exit_reason_str(run->exit_reason));
74
75 if (get_ucall(vcpu, &uc))
76 break;
77
78 TEST_ASSERT(run->io.port == 0x80,
79 "Expected I/O at port 0x80, got port 0x%x\n", run->io.port);
80
81 /*
82 * Modify the rep string count in RCX: 2 => 1 and 3 => 8192.
83 * Note, this abuses KVM's batching of rep string I/O to avoid
84 * getting stuck in an infinite loop. That behavior isn't in
85 * scope from a testing perspective as it's not ABI in any way,
86 * i.e. it really is abusing internal KVM knowledge.
87 */
88 vcpu_regs_get(vcpu, ®s);
89 if (regs.rcx == 2)
90 regs.rcx = 1;
91 if (regs.rcx == 3)
92 regs.rcx = 8192;
93 memset((void *)run + run->io.data_offset, 0xaa, 4096);
94 vcpu_regs_set(vcpu, ®s);
95 }
96
97 switch (uc.cmd) {
98 case UCALL_DONE:
99 break;
100 case UCALL_ABORT:
101 REPORT_GUEST_ASSERT_2(uc, "argN+1 = 0x%lx, argN+2 = 0x%lx");
102 default:
103 TEST_FAIL("Unknown ucall %lu", uc.cmd);
104 }
105
106 kvm_vm_free(vm);
107 return 0;
108 }
109
