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 13 void ucall_init(struct kvm_vm *vm, void *arg) 14 { 15 } 16 17 void ucall_uninit(struct kvm_vm *vm) 18 { 19 } 20 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 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 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