xref: /linux/tools/testing/selftests/kvm/riscv/arch_timer.c (revision 249ebf3f65f8530beb2cbfb91bff1d83ba88d23c)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * arch_timer.c - Tests the riscv64 sstc timer IRQ functionality
4  *
5  * The test validates the sstc timer IRQs using vstimecmp registers.
6  * It's ported from the aarch64 arch_timer test.
7  *
8  * Copyright (c) 2024, Intel Corporation.
9  */
10 #include "arch_timer.h"
11 #include "kvm_util.h"
12 #include "processor.h"
13 #include "timer_test.h"
14 #include "ucall_common.h"
15 
16 static int timer_irq = IRQ_S_TIMER;
17 
18 static void guest_irq_handler(struct ex_regs *regs)
19 {
20 	uint64_t xcnt, xcnt_diff_us, cmp;
21 	unsigned int intid = regs->cause & ~CAUSE_IRQ_FLAG;
22 	uint32_t cpu = guest_get_vcpuid();
23 	struct test_vcpu_shared_data *shared_data = &vcpu_shared_data[cpu];
24 
25 	timer_irq_disable();
26 
27 	xcnt = timer_get_cycles();
28 	cmp = timer_get_cmp();
29 	xcnt_diff_us = cycles_to_usec(xcnt - shared_data->xcnt);
30 
31 	/* Make sure we are dealing with the correct timer IRQ */
32 	GUEST_ASSERT_EQ(intid, timer_irq);
33 
34 	__GUEST_ASSERT(xcnt >= cmp,
35 			"xcnt = 0x%"PRIx64", cmp = 0x%"PRIx64", xcnt_diff_us = 0x%" PRIx64,
36 			xcnt, cmp, xcnt_diff_us);
37 
38 	WRITE_ONCE(shared_data->nr_iter, shared_data->nr_iter + 1);
39 }
40 
41 static void guest_run(struct test_vcpu_shared_data *shared_data)
42 {
43 	uint32_t irq_iter, config_iter;
44 
45 	shared_data->nr_iter = 0;
46 	shared_data->guest_stage = 0;
47 
48 	for (config_iter = 0; config_iter < test_args.nr_iter; config_iter++) {
49 		/* Setup the next interrupt */
50 		timer_set_next_cmp_ms(test_args.timer_period_ms);
51 		shared_data->xcnt = timer_get_cycles();
52 		timer_irq_enable();
53 
54 		/* Setup a timeout for the interrupt to arrive */
55 		udelay(msecs_to_usecs(test_args.timer_period_ms) +
56 			test_args.timer_err_margin_us);
57 
58 		irq_iter = READ_ONCE(shared_data->nr_iter);
59 		__GUEST_ASSERT(config_iter + 1 == irq_iter,
60 				"config_iter + 1 = 0x%x, irq_iter = 0x%x.\n"
61 				"  Guest timer interrupt was not triggered within the specified\n"
62 				"  interval, try to increase the error margin by [-e] option.\n",
63 				config_iter + 1, irq_iter);
64 	}
65 }
66 
67 static void guest_code(void)
68 {
69 	uint32_t cpu = guest_get_vcpuid();
70 	struct test_vcpu_shared_data *shared_data = &vcpu_shared_data[cpu];
71 
72 	timer_irq_disable();
73 	local_irq_enable();
74 
75 	guest_run(shared_data);
76 
77 	GUEST_DONE();
78 }
79 
80 struct kvm_vm *test_vm_create(void)
81 {
82 	struct kvm_vm *vm;
83 	int nr_vcpus = test_args.nr_vcpus;
84 
85 	vm = vm_create_with_vcpus(nr_vcpus, guest_code, vcpus);
86 	__TEST_REQUIRE(__vcpu_has_isa_ext(vcpus[0], KVM_RISCV_ISA_EXT_SSTC),
87 				   "SSTC not available, skipping test\n");
88 
89 	vm_init_vector_tables(vm);
90 	vm_install_interrupt_handler(vm, guest_irq_handler);
91 
92 	for (int i = 0; i < nr_vcpus; i++)
93 		vcpu_init_vector_tables(vcpus[i]);
94 
95 	/* Initialize guest timer frequency. */
96 	vcpu_get_reg(vcpus[0], RISCV_TIMER_REG(frequency), &timer_freq);
97 	sync_global_to_guest(vm, timer_freq);
98 	pr_debug("timer_freq: %lu\n", timer_freq);
99 
100 	/* Make all the test's cmdline args visible to the guest */
101 	sync_global_to_guest(vm, test_args);
102 
103 	return vm;
104 }
105 
106 void test_vm_cleanup(struct kvm_vm *vm)
107 {
108 	kvm_vm_free(vm);
109 }
110