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 "../kvm_util_internal.h"
12 #include "processor.h"
13
ucall_init(struct kvm_vm * vm,void * arg)14 void ucall_init(struct kvm_vm *vm, void *arg)
15 {
16 }
17
ucall_uninit(struct kvm_vm * vm)18 void ucall_uninit(struct kvm_vm *vm)
19 {
20 }
21
sbi_ecall(int ext,int fid,unsigned long arg0,unsigned long arg1,unsigned long arg2,unsigned long arg3,unsigned long arg4,unsigned long arg5)22 struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0,
23 unsigned long arg1, unsigned long arg2,
24 unsigned long arg3, unsigned long arg4,
25 unsigned long arg5)
26 {
27 register uintptr_t a0 asm ("a0") = (uintptr_t)(arg0);
28 register uintptr_t a1 asm ("a1") = (uintptr_t)(arg1);
29 register uintptr_t a2 asm ("a2") = (uintptr_t)(arg2);
30 register uintptr_t a3 asm ("a3") = (uintptr_t)(arg3);
31 register uintptr_t a4 asm ("a4") = (uintptr_t)(arg4);
32 register uintptr_t a5 asm ("a5") = (uintptr_t)(arg5);
33 register uintptr_t a6 asm ("a6") = (uintptr_t)(fid);
34 register uintptr_t a7 asm ("a7") = (uintptr_t)(ext);
35 struct sbiret ret;
36
37 asm volatile (
38 "ecall"
39 : "+r" (a0), "+r" (a1)
40 : "r" (a2), "r" (a3), "r" (a4), "r" (a5), "r" (a6), "r" (a7)
41 : "memory");
42 ret.error = a0;
43 ret.value = a1;
44
45 return ret;
46 }
47
ucall(uint64_t cmd,int nargs,...)48 void ucall(uint64_t cmd, int nargs, ...)
49 {
50 struct ucall uc = {
51 .cmd = cmd,
52 };
53 va_list va;
54 int i;
55
56 nargs = nargs <= UCALL_MAX_ARGS ? nargs : UCALL_MAX_ARGS;
57
58 va_start(va, nargs);
59 for (i = 0; i < nargs; ++i)
60 uc.args[i] = va_arg(va, uint64_t);
61 va_end(va);
62
63 sbi_ecall(KVM_RISCV_SELFTESTS_SBI_EXT, 0, (vm_vaddr_t)&uc,
64 0, 0, 0, 0, 0);
65 }
66
get_ucall(struct kvm_vm * vm,uint32_t vcpu_id,struct ucall * uc)67 uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, struct ucall *uc)
68 {
69 struct kvm_run *run = vcpu_state(vm, vcpu_id);
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 run->riscv_sbi.function_id == 0) {
78 memcpy(&ucall, addr_gva2hva(vm, run->riscv_sbi.args[0]),
79 sizeof(ucall));
80
81 vcpu_run_complete_io(vm, vcpu_id);
82 if (uc)
83 memcpy(uc, &ucall, sizeof(ucall));
84 }
85
86 return ucall.cmd;
87 }
88