xref: /linux/tools/testing/selftests/kvm/riscv/ebreak_test.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * RISC-V KVM ebreak test.
4  *
5  * Copyright 2024 Beijing ESWIN Computing Technology Co., Ltd.
6  *
7  */
8 #include "kvm_util.h"
9 #include "ucall_common.h"
10 
11 #define LABEL_ADDRESS(v) ((uint64_t)&(v))
12 
13 extern unsigned char sw_bp_1, sw_bp_2;
14 static uint64_t sw_bp_addr;
15 
16 static void guest_code(void)
17 {
18 	asm volatile(
19 		".option push\n"
20 		".option norvc\n"
21 		"sw_bp_1: ebreak\n"
22 		"sw_bp_2: ebreak\n"
23 		".option pop\n"
24 	);
25 	GUEST_ASSERT_EQ(READ_ONCE(sw_bp_addr), LABEL_ADDRESS(sw_bp_2));
26 
27 	GUEST_DONE();
28 }
29 
30 static void guest_breakpoint_handler(struct ex_regs *regs)
31 {
32 	WRITE_ONCE(sw_bp_addr, regs->epc);
33 	regs->epc += 4;
34 }
35 
36 int main(void)
37 {
38 	struct kvm_vm *vm;
39 	struct kvm_vcpu *vcpu;
40 	uint64_t pc;
41 	struct kvm_guest_debug debug = {
42 		.control = KVM_GUESTDBG_ENABLE,
43 	};
44 
45 	TEST_REQUIRE(kvm_has_cap(KVM_CAP_SET_GUEST_DEBUG));
46 
47 	vm = vm_create_with_one_vcpu(&vcpu, guest_code);
48 
49 	vm_init_vector_tables(vm);
50 	vcpu_init_vector_tables(vcpu);
51 	vm_install_exception_handler(vm, EXC_BREAKPOINT,
52 					guest_breakpoint_handler);
53 
54 	/*
55 	 * Enable the guest debug.
56 	 * ebreak should exit to the VMM with KVM_EXIT_DEBUG reason.
57 	 */
58 	vcpu_guest_debug_set(vcpu, &debug);
59 	vcpu_run(vcpu);
60 
61 	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_DEBUG);
62 
63 	vcpu_get_reg(vcpu, RISCV_CORE_REG(regs.pc), &pc);
64 	TEST_ASSERT_EQ(pc, LABEL_ADDRESS(sw_bp_1));
65 
66 	/* skip sw_bp_1 */
67 	vcpu_set_reg(vcpu, RISCV_CORE_REG(regs.pc), pc + 4);
68 
69 	/*
70 	 * Disable all debug controls.
71 	 * Guest should handle the ebreak without exiting to the VMM.
72 	 */
73 	memset(&debug, 0, sizeof(debug));
74 	vcpu_guest_debug_set(vcpu, &debug);
75 
76 	vcpu_run(vcpu);
77 
78 	TEST_ASSERT_EQ(get_ucall(vcpu, NULL), UCALL_DONE);
79 
80 	kvm_vm_free(vm);
81 
82 	return 0;
83 }
84