1 files changed, 98 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/lib/riscv/ucall.c b/tools/testing/selftests/kvm/lib/riscv/ucall.c
new file mode 100644
index 000000000000..087b9740bc8f
--- /dev/null
+++ b/tools/testing/selftests/kvm/lib/riscv/ucall.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ucall support. A ucall is a "hypercall to userspace".
+ *
+ * Copyright (C) 2021 Western Digital Corporation or its affiliates.
+ */
+
+#include <linux/kvm.h>
+
+#include "kvm_util.h"
+#include "processor.h"
+
+void ucall_init(struct kvm_vm *vm, void *arg)
+{
+}
+
+void ucall_uninit(struct kvm_vm *vm)
+{
+}
+
+struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0,
+			unsigned long arg1, unsigned long arg2,
+			unsigned long arg3, unsigned long arg4,
+			unsigned long arg5)
+{
+	register uintptr_t a0 asm ("a0") = (uintptr_t)(arg0);
+	register uintptr_t a1 asm ("a1") = (uintptr_t)(arg1);
+	register uintptr_t a2 asm ("a2") = (uintptr_t)(arg2);
+	register uintptr_t a3 asm ("a3") = (uintptr_t)(arg3);
+	register uintptr_t a4 asm ("a4") = (uintptr_t)(arg4);
+	register uintptr_t a5 asm ("a5") = (uintptr_t)(arg5);
+	register uintptr_t a6 asm ("a6") = (uintptr_t)(fid);
+	register uintptr_t a7 asm ("a7") = (uintptr_t)(ext);
+	struct sbiret ret;
+
+	asm volatile (
+		"ecall"
+		: "+r" (a0), "+r" (a1)
+		: "r" (a2), "r" (a3), "r" (a4), "r" (a5), "r" (a6), "r" (a7)
+		: "memory");
+	ret.error = a0;
+	ret.value = a1;
+
+	return ret;
+}
+
+void ucall(uint64_t cmd, int nargs, ...)
+{
+	struct ucall uc = {
+		.cmd = cmd,
+	};
+	va_list va;
+	int i;
+
+	nargs = min(nargs, UCALL_MAX_ARGS);
+
+	va_start(va, nargs);
+	for (i = 0; i < nargs; ++i)
+		uc.args[i] = va_arg(va, uint64_t);
+	va_end(va);
+
+	sbi_ecall(KVM_RISCV_SELFTESTS_SBI_EXT,
+		  KVM_RISCV_SELFTESTS_SBI_UCALL,
+		  (vm_vaddr_t)&uc, 0, 0, 0, 0, 0);
+}
+
+uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc)
+{
+	struct kvm_run *run = vcpu->run;
+	struct ucall ucall = {};
+
+	if (uc)
+		memset(uc, 0, sizeof(*uc));
+
+	if (run->exit_reason == KVM_EXIT_RISCV_SBI &&
+	    run->riscv_sbi.extension_id == KVM_RISCV_SELFTESTS_SBI_EXT) {
+		switch (run->riscv_sbi.function_id) {
+		case KVM_RISCV_SELFTESTS_SBI_UCALL:
+			memcpy(&ucall,
+			       addr_gva2hva(vcpu->vm, run->riscv_sbi.args[0]),
+			       sizeof(ucall));
+
+			vcpu_run_complete_io(vcpu);
+			if (uc)
+				memcpy(uc, &ucall, sizeof(ucall));
+
+			break;
+		case KVM_RISCV_SELFTESTS_SBI_UNEXP:
+			vcpu_dump(stderr, vcpu, 2);
+			TEST_ASSERT(0, "Unexpected trap taken by guest");
+			break;
+		default:
+			break;
+		}
+	}
+
+	return ucall.cmd;
+}