xref: /openbmc/linux/arch/riscv/kvm/main.c (revision 81a1cf9f89a6b71e71bfd7d43837ce9235e70b38)
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 	csr_write(CSR_HCOUNTEREN, -1UL);
43 
44 	csr_write(CSR_HVIP, 0);
45 
46 	return 0;
47 }
48 
49 void kvm_arch_hardware_disable(void)
50 {
51 	/*
52 	 * After clearing the hideleg CSR, the host kernel will receive
53 	 * spurious interrupts if hvip CSR has pending interrupts and the
54 	 * corresponding enable bits in vsie CSR are asserted. To avoid it,
55 	 * hvip CSR and vsie CSR must be cleared before clearing hideleg CSR.
56 	 */
57 	csr_write(CSR_VSIE, 0);
58 	csr_write(CSR_HVIP, 0);
59 	csr_write(CSR_HEDELEG, 0);
60 	csr_write(CSR_HIDELEG, 0);
61 }
62 
63 static int __init riscv_kvm_init(void)
64 {
65 	const char *str;
66 
67 	if (!riscv_isa_extension_available(NULL, h)) {
68 		kvm_info("hypervisor extension not available\n");
69 		return -ENODEV;
70 	}
71 
72 	if (sbi_spec_is_0_1()) {
73 		kvm_info("require SBI v0.2 or higher\n");
74 		return -ENODEV;
75 	}
76 
77 	if (sbi_probe_extension(SBI_EXT_RFENCE) <= 0) {
78 		kvm_info("require SBI RFENCE extension\n");
79 		return -ENODEV;
80 	}
81 
82 	kvm_riscv_gstage_mode_detect();
83 
84 	kvm_riscv_gstage_vmid_detect();
85 
86 	kvm_info("hypervisor extension available\n");
87 
88 	switch (kvm_riscv_gstage_mode()) {
89 	case HGATP_MODE_SV32X4:
90 		str = "Sv32x4";
91 		break;
92 	case HGATP_MODE_SV39X4:
93 		str = "Sv39x4";
94 		break;
95 	case HGATP_MODE_SV48X4:
96 		str = "Sv48x4";
97 		break;
98 	case HGATP_MODE_SV57X4:
99 		str = "Sv57x4";
100 		break;
101 	default:
102 		return -ENODEV;
103 	}
104 	kvm_info("using %s G-stage page table format\n", str);
105 
106 	kvm_info("VMID %ld bits available\n", kvm_riscv_gstage_vmid_bits());
107 
108 	return kvm_init(sizeof(struct kvm_vcpu), 0, THIS_MODULE);
109 }
110 module_init(riscv_kvm_init);
111 
112 static void __exit riscv_kvm_exit(void)
113 {
114 	kvm_exit();
115 }
116 module_exit(riscv_kvm_exit);
117