xref: /openbmc/linux/arch/riscv/kvm/main.c (revision 829c6524)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2019 Western Digital Corporation or its affiliates.
4  *
5  * Authors:
6  *     Anup Patel <anup.patel@wdc.com>
7  */
8 
9 #include <linux/errno.h>
10 #include <linux/err.h>
11 #include <linux/module.h>
12 #include <linux/kvm_host.h>
13 #include <asm/csr.h>
14 #include <asm/hwcap.h>
15 #include <asm/sbi.h>
16 
17 long kvm_arch_dev_ioctl(struct file *filp,
18 			unsigned int ioctl, unsigned long arg)
19 {
20 	return -EINVAL;
21 }
22 
23 int kvm_arch_hardware_enable(void)
24 {
25 	unsigned long hideleg, hedeleg;
26 
27 	hedeleg = 0;
28 	hedeleg |= (1UL << EXC_INST_MISALIGNED);
29 	hedeleg |= (1UL << EXC_BREAKPOINT);
30 	hedeleg |= (1UL << EXC_SYSCALL);
31 	hedeleg |= (1UL << EXC_INST_PAGE_FAULT);
32 	hedeleg |= (1UL << EXC_LOAD_PAGE_FAULT);
33 	hedeleg |= (1UL << EXC_STORE_PAGE_FAULT);
34 	csr_write(CSR_HEDELEG, hedeleg);
35 
36 	hideleg = 0;
37 	hideleg |= (1UL << IRQ_VS_SOFT);
38 	hideleg |= (1UL << IRQ_VS_TIMER);
39 	hideleg |= (1UL << IRQ_VS_EXT);
40 	csr_write(CSR_HIDELEG, hideleg);
41 
42 	/* VS should access only the time counter directly. Everything else should trap */
43 	csr_write(CSR_HCOUNTEREN, 0x02);
44 
45 	csr_write(CSR_HVIP, 0);
46 
47 	kvm_riscv_aia_enable();
48 
49 	return 0;
50 }
51 
52 void kvm_arch_hardware_disable(void)
53 {
54 	kvm_riscv_aia_disable();
55 
56 	/*
57 	 * After clearing the hideleg CSR, the host kernel will receive
58 	 * spurious interrupts if hvip CSR has pending interrupts and the
59 	 * corresponding enable bits in vsie CSR are asserted. To avoid it,
60 	 * hvip CSR and vsie CSR must be cleared before clearing hideleg CSR.
61 	 */
62 	csr_write(CSR_VSIE, 0);
63 	csr_write(CSR_HVIP, 0);
64 	csr_write(CSR_HEDELEG, 0);
65 	csr_write(CSR_HIDELEG, 0);
66 }
67 
68 static int __init riscv_kvm_init(void)
69 {
70 	int rc;
71 	const char *str;
72 
73 	if (!riscv_isa_extension_available(NULL, h)) {
74 		kvm_info("hypervisor extension not available\n");
75 		return -ENODEV;
76 	}
77 
78 	if (sbi_spec_is_0_1()) {
79 		kvm_info("require SBI v0.2 or higher\n");
80 		return -ENODEV;
81 	}
82 
83 	if (!sbi_probe_extension(SBI_EXT_RFENCE)) {
84 		kvm_info("require SBI RFENCE extension\n");
85 		return -ENODEV;
86 	}
87 
88 	kvm_riscv_gstage_mode_detect();
89 
90 	kvm_riscv_gstage_vmid_detect();
91 
92 	rc = kvm_riscv_aia_init();
93 	if (rc && rc != -ENODEV)
94 		return rc;
95 
96 	kvm_info("hypervisor extension available\n");
97 
98 	switch (kvm_riscv_gstage_mode()) {
99 	case HGATP_MODE_SV32X4:
100 		str = "Sv32x4";
101 		break;
102 	case HGATP_MODE_SV39X4:
103 		str = "Sv39x4";
104 		break;
105 	case HGATP_MODE_SV48X4:
106 		str = "Sv48x4";
107 		break;
108 	case HGATP_MODE_SV57X4:
109 		str = "Sv57x4";
110 		break;
111 	default:
112 		return -ENODEV;
113 	}
114 	kvm_info("using %s G-stage page table format\n", str);
115 
116 	kvm_info("VMID %ld bits available\n", kvm_riscv_gstage_vmid_bits());
117 
118 	if (kvm_riscv_aia_available())
119 		kvm_info("AIA available with %d guest external interrupts\n",
120 			 kvm_riscv_aia_nr_hgei);
121 
122 	rc = kvm_init(sizeof(struct kvm_vcpu), 0, THIS_MODULE);
123 	if (rc) {
124 		kvm_riscv_aia_exit();
125 		return rc;
126 	}
127 
128 	return 0;
129 }
130 module_init(riscv_kvm_init);
131 
132 static void __exit riscv_kvm_exit(void)
133 {
134 	kvm_riscv_aia_exit();
135 
136 	kvm_exit();
137 }
138 module_exit(riscv_kvm_exit);
139