1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * ucall support. A ucall is a "hypercall to userspace".
4 *
5 * Copyright (C) 2021 Western Digital Corporation or its affiliates.
6 */
7
8 #include <linux/kvm.h>
9
10 #include "kvm_util.h"
11 #include "processor.h"
12
ucall_init(struct kvm_vm * vm,void * arg)13 void ucall_init(struct kvm_vm *vm, void *arg)
14 {
15 }
16
ucall_uninit(struct kvm_vm * vm)17 void ucall_uninit(struct kvm_vm *vm)
18 {
19 }
20
sbi_ecall(int ext,int fid,unsigned long arg0,unsigned long arg1,unsigned long arg2,unsigned long arg3,unsigned long arg4,unsigned long arg5)21 struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0,
22 unsigned long arg1, unsigned long arg2,
23 unsigned long arg3, unsigned long arg4,
24 unsigned long arg5)
25 {
26 register uintptr_t a0 asm ("a0") = (uintptr_t)(arg0);
27 register uintptr_t a1 asm ("a1") = (uintptr_t)(arg1);
28 register uintptr_t a2 asm ("a2") = (uintptr_t)(arg2);
29 register uintptr_t a3 asm ("a3") = (uintptr_t)(arg3);
30 register uintptr_t a4 asm ("a4") = (uintptr_t)(arg4);
31 register uintptr_t a5 asm ("a5") = (uintptr_t)(arg5);
32 register uintptr_t a6 asm ("a6") = (uintptr_t)(fid);
33 register uintptr_t a7 asm ("a7") = (uintptr_t)(ext);
34 struct sbiret ret;
35
36 asm volatile (
37 "ecall"
38 : "+r" (a0), "+r" (a1)
39 : "r" (a2), "r" (a3), "r" (a4), "r" (a5), "r" (a6), "r" (a7)
40 : "memory");
41 ret.error = a0;
42 ret.value = a1;
43
44 return ret;
45 }
46
ucall(uint64_t cmd,int nargs,...)47 void ucall(uint64_t cmd, int nargs, ...)
48 {
49 struct ucall uc = {
50 .cmd = cmd,
51 };
52 va_list va;
53 int i;
54
55 nargs = min(nargs, UCALL_MAX_ARGS);
56
57 va_start(va, nargs);
58 for (i = 0; i < nargs; ++i)
59 uc.args[i] = va_arg(va, uint64_t);
60 va_end(va);
61
62 sbi_ecall(KVM_RISCV_SELFTESTS_SBI_EXT,
63 KVM_RISCV_SELFTESTS_SBI_UCALL,
64 (vm_vaddr_t)&uc, 0, 0, 0, 0, 0);
65 }
66
get_ucall(struct kvm_vcpu * vcpu,struct ucall * uc)67 uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc)
68 {
69 struct kvm_run *run = vcpu->run;
70 struct ucall ucall = {};
71
72 if (uc)
73 memset(uc, 0, sizeof(*uc));
74
75 if (run->exit_reason == KVM_EXIT_RISCV_SBI &&
76 run->riscv_sbi.extension_id == KVM_RISCV_SELFTESTS_SBI_EXT) {
77 switch (run->riscv_sbi.function_id) {
78 case KVM_RISCV_SELFTESTS_SBI_UCALL:
79 memcpy(&ucall,
80 addr_gva2hva(vcpu->vm, run->riscv_sbi.args[0]),
81 sizeof(ucall));
82
83 vcpu_run_complete_io(vcpu);
84 if (uc)
85 memcpy(uc, &ucall, sizeof(ucall));
86
87 break;
88 case KVM_RISCV_SELFTESTS_SBI_UNEXP:
89 vcpu_dump(stderr, vcpu, 2);
90 TEST_ASSERT(0, "Unexpected trap taken by guest");
91 break;
92 default:
93 break;
94 }
95 }
96
97 return ucall.cmd;
98 }
99