[kvm-unit-tests GIT PULL 16/17] lib: s390x: snippet.h: Add a few constants that will make our life easier

Janosch Frank
2021-10-18T12:38:22Z

The variable names for the snippet objects are of gigantic length so
let's define a few macros to make them easier to read.

Also add a standard PSW which should be used to start the snippet.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
---
lib/s390x/snippet.h | 34 ++++++++++++++++++++++++++++++++++
s390x/mvpg-sie.c | 13 ++++++-------
2 files changed, 40 insertions(+), 7 deletions(-)
create mode 100644 lib/s390x/snippet.h

diff --git a/lib/s390x/snippet.h b/lib/s390x/snippet.h
new file mode 100644
index 00000000..8e4765f8
--- /dev/null
+++ b/lib/s390x/snippet.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Snippet definitions
+ *
+ * Copyright IBM Corp. 2021
+ * Author: Janosch Frank <frankja@linux.ibm.com>
+ */
+
+#ifndef _S390X_SNIPPET_H_
+#define _S390X_SNIPPET_H_
+
+/* This macro cuts down the length of the pointers to snippets */
+#define SNIPPET_NAME_START(type, file) \
+ _binary_s390x_snippets_##type##_##file##_gbin_start
+#define SNIPPET_NAME_END(type, file) \
+ _binary_s390x_snippets_##type##_##file##_gbin_end
+
+/* Returns the length of the snippet */
+#define SNIPPET_LEN(type, file) \
+ ((uintptr_t)SNIPPET_NAME_END(type, file) - (uintptr_t)SNIPPET_NAME_START(type, file))
+
+/*
+ * C snippet instructions start at 0x4000 due to the prefix and the
+ * stack being before that. ASM snippets don't strictly need a stack
+ * but keeping the starting address the same means less code.
+ */
+#define SNIPPET_ENTRY_ADDR 0x4000
+
+/* Standard entry PSWs for snippets which can simply be copied into the guest PSW */
+static const struct psw snippet_psw = {
+ .mask = PSW_MASK_64,
+ .addr = SNIPPET_ENTRY_ADDR,
+};
+#endif
diff --git a/s390x/mvpg-sie.c b/s390x/mvpg-sie.c
index 5adcec1e..d526069d 100644
--- a/s390x/mvpg-sie.c
+++ b/s390x/mvpg-sie.c
@@ -19,6 +19,7 @@
#include <vm.h>
#include <sclp.h>
#include <sie.h>
+#include <snippet.h>

static u8 *guest;
static struct vm vm;
@@ -27,8 +28,8 @@ static uint8_t *src;
static uint8_t *dst;
static uint8_t *cmp;

-extern const char _binary_s390x_snippets_c_mvpg_snippet_gbin_start[];
-extern const char _binary_s390x_snippets_c_mvpg_snippet_gbin_end[];
+extern const char SNIPPET_NAME_START(c, mvpg_snippet)[];
+extern const char SNIPPET_NAME_END(c, mvpg_snippet)[];
int binary_size;

static void test_mvpg_pei(void)
@@ -77,10 +78,9 @@ static void test_mvpg_pei(void)

static void test_mvpg(void)
{
- int binary_size = ((uintptr_t)_binary_s390x_snippets_c_mvpg_snippet_gbin_end -
- (uintptr_t)_binary_s390x_snippets_c_mvpg_snippet_gbin_start);
+ int binary_size = SNIPPET_LEN(c, mvpg_snippet);

- memcpy(guest, _binary_s390x_snippets_c_mvpg_snippet_gbin_start, binary_size);
+ memcpy(guest, SNIPPET_NAME_START(c, mvpg_snippet), binary_size);
memset(src, 0x42, PAGE_SIZE);
memset(dst, 0x43, PAGE_SIZE);
sie(&vm);
@@ -96,8 +96,7 @@ static void setup_guest(void)

sie_guest_create(&vm, (uint64_t)guest, HPAGE_SIZE);

- vm.sblk->gpsw.addr = PAGE_SIZE * 4;
- vm.sblk->gpsw.mask = PSW_MASK_64;
+ vm.sblk->gpsw = snippet_psw;
vm.sblk->ictl = ICTL_OPEREXC | ICTL_PINT;
/* Enable MVPG interpretation as we want to test KVM and not ourselves */
vm.sblk->eca = ECA_MVPGI;
--
2.31.1