xref: /openbmc/linux/arch/riscv/kvm/main.c (revision 94d964e5)
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_check_processor_compat(void *opaque)
24 {
25 	return 0;
26 }
27 
28 int kvm_arch_hardware_setup(void *opaque)
29 {
30 	return 0;
31 }
32 
33 int kvm_arch_hardware_enable(void)
34 {
35 	unsigned long hideleg, hedeleg;
36 
37 	hedeleg = 0;
38 	hedeleg |= (1UL << EXC_INST_MISALIGNED);
39 	hedeleg |= (1UL << EXC_BREAKPOINT);
40 	hedeleg |= (1UL << EXC_SYSCALL);
41 	hedeleg |= (1UL << EXC_INST_PAGE_FAULT);
42 	hedeleg |= (1UL << EXC_LOAD_PAGE_FAULT);
43 	hedeleg |= (1UL << EXC_STORE_PAGE_FAULT);
44 	csr_write(CSR_HEDELEG, hedeleg);
45 
46 	hideleg = 0;
47 	hideleg |= (1UL << IRQ_VS_SOFT);
48 	hideleg |= (1UL << IRQ_VS_TIMER);
49 	hideleg |= (1UL << IRQ_VS_EXT);
50 	csr_write(CSR_HIDELEG, hideleg);
51 
52 	csr_write(CSR_HCOUNTEREN, -1UL);
53 
54 	csr_write(CSR_HVIP, 0);
55 
56 	return 0;
57 }
58 
59 void kvm_arch_hardware_disable(void)
60 {
61 	/*
62 	 * After clearing the hideleg CSR, the host kernel will receive
63 	 * spurious interrupts if hvip CSR has pending interrupts and the
64 	 * corresponding enable bits in vsie CSR are asserted. To avoid it,
65 	 * hvip CSR and vsie CSR must be cleared before clearing hideleg CSR.
66 	 */
67 	csr_write(CSR_VSIE, 0);
68 	csr_write(CSR_HVIP, 0);
69 	csr_write(CSR_HEDELEG, 0);
70 	csr_write(CSR_HIDELEG, 0);
71 }
72 
73 int kvm_arch_init(void *opaque)
74 {
75 	const char *str;
76 
77 	if (!riscv_isa_extension_available(NULL, h)) {
78 		kvm_info("hypervisor extension not available\n");
79 		return -ENODEV;
80 	}
81 
82 	if (sbi_spec_is_0_1()) {
83 		kvm_info("require SBI v0.2 or higher\n");
84 		return -ENODEV;
85 	}
86 
87 	if (sbi_probe_extension(SBI_EXT_RFENCE) <= 0) {
88 		kvm_info("require SBI RFENCE extension\n");
89 		return -ENODEV;
90 	}
91 
92 	kvm_riscv_stage2_mode_detect();
93 
94 	kvm_riscv_stage2_vmid_detect();
95 
96 	kvm_info("hypervisor extension available\n");
97 
98 	switch (kvm_riscv_stage2_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 	default:
109 		return -ENODEV;
110 	}
111 	kvm_info("using %s G-stage page table format\n", str);
112 
113 	kvm_info("VMID %ld bits available\n", kvm_riscv_stage2_vmid_bits());
114 
115 	return 0;
116 }
117 
118 void kvm_arch_exit(void)
119 {
120 }
121 
122 static int riscv_kvm_init(void)
123 {
124 	return kvm_init(NULL, sizeof(struct kvm_vcpu), 0, THIS_MODULE);
125 }
126 module_init(riscv_kvm_init);
127