xref: /linux/arch/riscv/kvm/vcpu_vector.c (revision 24168c5e6dfbdd5b414f048f47f75d64533296ca)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2022 SiFive
4  *
5  * Authors:
6  *     Vincent Chen <vincent.chen@sifive.com>
7  *     Greentime Hu <greentime.hu@sifive.com>
8  */
9 
10 #include <linux/errno.h>
11 #include <linux/err.h>
12 #include <linux/kvm_host.h>
13 #include <linux/uaccess.h>
14 #include <asm/cpufeature.h>
15 #include <asm/kvm_vcpu_vector.h>
16 #include <asm/vector.h>
17 
18 #ifdef CONFIG_RISCV_ISA_V
19 void kvm_riscv_vcpu_vector_reset(struct kvm_vcpu *vcpu)
20 {
21 	unsigned long *isa = vcpu->arch.isa;
22 	struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;
23 
24 	cntx->sstatus &= ~SR_VS;
25 	if (riscv_isa_extension_available(isa, v)) {
26 		cntx->sstatus |= SR_VS_INITIAL;
27 		WARN_ON(!cntx->vector.datap);
28 		memset(cntx->vector.datap, 0, riscv_v_vsize);
29 	} else {
30 		cntx->sstatus |= SR_VS_OFF;
31 	}
32 }
33 
34 static void kvm_riscv_vcpu_vector_clean(struct kvm_cpu_context *cntx)
35 {
36 	cntx->sstatus &= ~SR_VS;
37 	cntx->sstatus |= SR_VS_CLEAN;
38 }
39 
40 void kvm_riscv_vcpu_guest_vector_save(struct kvm_cpu_context *cntx,
41 				      unsigned long *isa)
42 {
43 	if ((cntx->sstatus & SR_VS) == SR_VS_DIRTY) {
44 		if (riscv_isa_extension_available(isa, v))
45 			__kvm_riscv_vector_save(cntx);
46 		kvm_riscv_vcpu_vector_clean(cntx);
47 	}
48 }
49 
50 void kvm_riscv_vcpu_guest_vector_restore(struct kvm_cpu_context *cntx,
51 					 unsigned long *isa)
52 {
53 	if ((cntx->sstatus & SR_VS) != SR_VS_OFF) {
54 		if (riscv_isa_extension_available(isa, v))
55 			__kvm_riscv_vector_restore(cntx);
56 		kvm_riscv_vcpu_vector_clean(cntx);
57 	}
58 }
59 
60 void kvm_riscv_vcpu_host_vector_save(struct kvm_cpu_context *cntx)
61 {
62 	/* No need to check host sstatus as it can be modified outside */
63 	if (riscv_isa_extension_available(NULL, v))
64 		__kvm_riscv_vector_save(cntx);
65 }
66 
67 void kvm_riscv_vcpu_host_vector_restore(struct kvm_cpu_context *cntx)
68 {
69 	if (riscv_isa_extension_available(NULL, v))
70 		__kvm_riscv_vector_restore(cntx);
71 }
72 
73 int kvm_riscv_vcpu_alloc_vector_context(struct kvm_vcpu *vcpu,
74 					struct kvm_cpu_context *cntx)
75 {
76 	cntx->vector.datap = kmalloc(riscv_v_vsize, GFP_KERNEL);
77 	if (!cntx->vector.datap)
78 		return -ENOMEM;
79 	cntx->vector.vlenb = riscv_v_vsize / 32;
80 
81 	vcpu->arch.host_context.vector.datap = kzalloc(riscv_v_vsize, GFP_KERNEL);
82 	if (!vcpu->arch.host_context.vector.datap)
83 		return -ENOMEM;
84 
85 	return 0;
86 }
87 
88 void kvm_riscv_vcpu_free_vector_context(struct kvm_vcpu *vcpu)
89 {
90 	kfree(vcpu->arch.guest_reset_context.vector.datap);
91 	kfree(vcpu->arch.host_context.vector.datap);
92 }
93 #endif
94 
95 static int kvm_riscv_vcpu_vreg_addr(struct kvm_vcpu *vcpu,
96 				    unsigned long reg_num,
97 				    size_t reg_size,
98 				    void **reg_addr)
99 {
100 	struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;
101 	size_t vlenb = riscv_v_vsize / 32;
102 
103 	if (reg_num < KVM_REG_RISCV_VECTOR_REG(0)) {
104 		if (reg_size != sizeof(unsigned long))
105 			return -EINVAL;
106 		switch (reg_num) {
107 		case KVM_REG_RISCV_VECTOR_CSR_REG(vstart):
108 			*reg_addr = &cntx->vector.vstart;
109 			break;
110 		case KVM_REG_RISCV_VECTOR_CSR_REG(vl):
111 			*reg_addr = &cntx->vector.vl;
112 			break;
113 		case KVM_REG_RISCV_VECTOR_CSR_REG(vtype):
114 			*reg_addr = &cntx->vector.vtype;
115 			break;
116 		case KVM_REG_RISCV_VECTOR_CSR_REG(vcsr):
117 			*reg_addr = &cntx->vector.vcsr;
118 			break;
119 		case KVM_REG_RISCV_VECTOR_CSR_REG(vlenb):
120 			*reg_addr = &cntx->vector.vlenb;
121 			break;
122 		case KVM_REG_RISCV_VECTOR_CSR_REG(datap):
123 		default:
124 			return -ENOENT;
125 		}
126 	} else if (reg_num <= KVM_REG_RISCV_VECTOR_REG(31)) {
127 		if (reg_size != vlenb)
128 			return -EINVAL;
129 		*reg_addr = cntx->vector.datap +
130 			    (reg_num - KVM_REG_RISCV_VECTOR_REG(0)) * vlenb;
131 	} else {
132 		return -ENOENT;
133 	}
134 
135 	return 0;
136 }
137 
138 int kvm_riscv_vcpu_get_reg_vector(struct kvm_vcpu *vcpu,
139 				  const struct kvm_one_reg *reg)
140 {
141 	unsigned long *isa = vcpu->arch.isa;
142 	unsigned long __user *uaddr =
143 			(unsigned long __user *)(unsigned long)reg->addr;
144 	unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
145 					    KVM_REG_SIZE_MASK |
146 					    KVM_REG_RISCV_VECTOR);
147 	size_t reg_size = KVM_REG_SIZE(reg->id);
148 	void *reg_addr;
149 	int rc;
150 
151 	if (!riscv_isa_extension_available(isa, v))
152 		return -ENOENT;
153 
154 	rc = kvm_riscv_vcpu_vreg_addr(vcpu, reg_num, reg_size, &reg_addr);
155 	if (rc)
156 		return rc;
157 
158 	if (copy_to_user(uaddr, reg_addr, reg_size))
159 		return -EFAULT;
160 
161 	return 0;
162 }
163 
164 int kvm_riscv_vcpu_set_reg_vector(struct kvm_vcpu *vcpu,
165 				  const struct kvm_one_reg *reg)
166 {
167 	unsigned long *isa = vcpu->arch.isa;
168 	unsigned long __user *uaddr =
169 			(unsigned long __user *)(unsigned long)reg->addr;
170 	unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
171 					    KVM_REG_SIZE_MASK |
172 					    KVM_REG_RISCV_VECTOR);
173 	size_t reg_size = KVM_REG_SIZE(reg->id);
174 	void *reg_addr;
175 	int rc;
176 
177 	if (!riscv_isa_extension_available(isa, v))
178 		return -ENOENT;
179 
180 	if (reg_num == KVM_REG_RISCV_VECTOR_CSR_REG(vlenb)) {
181 		struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;
182 		unsigned long reg_val;
183 
184 		if (copy_from_user(&reg_val, uaddr, reg_size))
185 			return -EFAULT;
186 		if (reg_val != cntx->vector.vlenb)
187 			return -EINVAL;
188 
189 		return 0;
190 	}
191 
192 	rc = kvm_riscv_vcpu_vreg_addr(vcpu, reg_num, reg_size, &reg_addr);
193 	if (rc)
194 		return rc;
195 
196 	if (copy_from_user(reg_addr, uaddr, reg_size))
197 		return -EFAULT;
198 
199 	return 0;
200 }
201