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
13struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0,
14			unsigned long arg1, unsigned long arg2,
15			unsigned long arg3, unsigned long arg4,
16			unsigned long arg5)
17{
18	register uintptr_t a0 asm ("a0") = (uintptr_t)(arg0);
19	register uintptr_t a1 asm ("a1") = (uintptr_t)(arg1);
20	register uintptr_t a2 asm ("a2") = (uintptr_t)(arg2);
21	register uintptr_t a3 asm ("a3") = (uintptr_t)(arg3);
22	register uintptr_t a4 asm ("a4") = (uintptr_t)(arg4);
23	register uintptr_t a5 asm ("a5") = (uintptr_t)(arg5);
24	register uintptr_t a6 asm ("a6") = (uintptr_t)(fid);
25	register uintptr_t a7 asm ("a7") = (uintptr_t)(ext);
26	struct sbiret ret;
27
28	asm volatile (
29		"ecall"
30		: "+r" (a0), "+r" (a1)
31		: "r" (a2), "r" (a3), "r" (a4), "r" (a5), "r" (a6), "r" (a7)
32		: "memory");
33	ret.error = a0;
34	ret.value = a1;
35
36	return ret;
37}
38
39void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu)
40{
41	struct kvm_run *run = vcpu->run;
42
43	if (run->exit_reason == KVM_EXIT_RISCV_SBI &&
44	    run->riscv_sbi.extension_id == KVM_RISCV_SELFTESTS_SBI_EXT) {
45		switch (run->riscv_sbi.function_id) {
46		case KVM_RISCV_SELFTESTS_SBI_UCALL:
47			return (void *)run->riscv_sbi.args[0];
48		case KVM_RISCV_SELFTESTS_SBI_UNEXP:
49			vcpu_dump(stderr, vcpu, 2);
50			TEST_ASSERT(0, "Unexpected trap taken by guest");
51			break;
52		default:
53			break;
54		}
55	}
56	return NULL;
57}
58