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Diffstat (limited to 'tools/testing/selftests/kvm/lib/s390x/ucall.c')
-rw-r--r--tools/testing/selftests/kvm/lib/s390x/ucall.c56
1 files changed, 56 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/lib/s390x/ucall.c b/tools/testing/selftests/kvm/lib/s390x/ucall.c
new file mode 100644
index 000000000000..fd589dc9bfab
--- /dev/null
+++ b/tools/testing/selftests/kvm/lib/s390x/ucall.c
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ucall support. A ucall is a "hypercall to userspace".
+ *
+ * Copyright (C) 2019 Red Hat, Inc.
+ */
+#include "kvm_util.h"
+
+void ucall_init(struct kvm_vm *vm, void *arg)
+{
+}
+
+void ucall_uninit(struct kvm_vm *vm)
+{
+}
+
+void ucall(uint64_t cmd, int nargs, ...)
+{
+ struct ucall uc = {
+ .cmd = cmd,
+ };
+ va_list va;
+ int i;
+
+ nargs = nargs <= UCALL_MAX_ARGS ? 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);
+
+ /* Exit via DIAGNOSE 0x501 (normally used for breakpoints) */
+ asm volatile ("diag 0,%0,0x501" : : "a"(&uc) : "memory");
+}
+
+uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, struct ucall *uc)
+{
+ struct kvm_run *run = vcpu_state(vm, vcpu_id);
+ struct ucall ucall = {};
+
+ if (run->exit_reason == KVM_EXIT_S390_SIEIC &&
+ run->s390_sieic.icptcode == 4 &&
+ (run->s390_sieic.ipa >> 8) == 0x83 && /* 0x83 means DIAGNOSE */
+ (run->s390_sieic.ipb >> 16) == 0x501) {
+ int reg = run->s390_sieic.ipa & 0xf;
+
+ memcpy(&ucall, addr_gva2hva(vm, run->s.regs.gprs[reg]),
+ sizeof(ucall));
+
+ vcpu_run_complete_io(vm, vcpu_id);
+ if (uc)
+ memcpy(uc, &ucall, sizeof(ucall));
+ }
+
+ return ucall.cmd;
+}