On 1/11/22 14:08, Claudio Imbrenda wrote:
On Mon, 10 Jan 2022 14:37:53 +0100
Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote:
We need in several tests to check if the VM we are running in
is KVM.
Let's add the test.
To check the VM type we use the STSI 3.2.2 instruction, let's
define it's response structure in a central header.
Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
---
lib/s390x/stsi.h | 32 ++++++++++++++++++++++++++++++++
lib/s390x/vm.c | 39 +++++++++++++++++++++++++++++++++++++++
lib/s390x/vm.h | 1 +
s390x/stsi.c | 23 ++---------------------
4 files changed, 74 insertions(+), 21 deletions(-)
create mode 100644 lib/s390x/stsi.h
diff --git a/lib/s390x/stsi.h b/lib/s390x/stsi.h
new file mode 100644
index 00000000..02cc94a6
--- /dev/null
+++ b/lib/s390x/stsi.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Structures used to Store System Information
+ *
+ * Copyright (c) 2021 IBM Inc
Copyright IBM Corp. 2021
OK
+ */
+
+#ifndef _S390X_STSI_H_
+#define _S390X_STSI_H_
[...]
+
+/**
+ * Detect whether we are running with KVM
+ */
+
+bool vm_is_kvm(void)
+{
+ /* EBCDIC for "KVM/" */
+ const uint8_t kvm_ebcdic[] = { 0xd2, 0xe5, 0xd4, 0x61 };
+ static bool initialized;
+ static bool is_kvm;
+ struct sysinfo_3_2_2 *stsi_322;
+
+ if (initialized)
+ return is_kvm;
+
+ if (stsi_get_fc() < 3) {
+ initialized = true;
+ return is_kvm;
+ }
+
+ stsi_322 = alloc_page();
+ if (!stsi_322)
+ return false;
I don't like returning false if the allocation fails.
The allocation should not fail: assert(stsi_322);
OK, right.
+
+ if (stsi(stsi_322, 3, 2, 2))
+ goto out;
+
Thanks for the review,
Pierre
--
Pierre Morel
IBM Lab Boeblingen
