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[Qemu-devel] [PATCH v2] Support running QEMU on Valgrind
From: |
Stefan Weil |
Subject: |
[Qemu-devel] [PATCH v2] Support running QEMU on Valgrind |
Date: |
Mon, 31 Oct 2011 21:29:46 +0100 |
Valgrind is a tool which can automatically detect many kinds of bugs.
Running QEMU on Valgrind with x86_64 hosts was not possible because
Valgrind aborts when memalign is called with an alignment larger than
1 MiB. QEMU normally uses 2 MiB on Linux x86_64.
Now the alignment is reduced to the page size when QEMU is running on
Valgrind.
v2:
Instead of using the macro RUNNING_ON_VALGRIND from valgrind.h,
the patch now uses a hack from libvirt which tests for the pre-loaded
vgpreload_*.so shared libraries. This avoids the need for valgrind.h.
Signed-off-by: Stefan Weil <address@hidden>
---
oslib-posix.c | 22 +++++++++++++++++++---
1 files changed, 19 insertions(+), 3 deletions(-)
diff --git a/oslib-posix.c b/oslib-posix.c
index dbc8ee8..6f29762 100644
--- a/oslib-posix.c
+++ b/oslib-posix.c
@@ -36,8 +36,11 @@ extern int daemon(int, int);
#endif
#if defined(__linux__) && defined(__x86_64__)
- /* Use 2MB alignment so transparent hugepages can be used by KVM */
+ /* Use 2 MiB alignment so transparent hugepages can be used by KVM.
+ Valgrind does not support alignments larger than 1 MiB,
+ therefore we need special code which handles running on Valgrind. */
# define QEMU_VMALLOC_ALIGN (512 * 4096)
+# define CONFIG_VALGRIND
#else
# define QEMU_VMALLOC_ALIGN getpagesize()
#endif
@@ -47,7 +50,11 @@ extern int daemon(int, int);
#include "trace.h"
#include "qemu_socket.h"
-
+#if defined(CONFIG_VALGRIND)
+static int running_on_valgrind = -1;
+#else
+# define running_on_valgrind 0
+#endif
int qemu_daemon(int nochdir, int noclose)
{
@@ -89,7 +96,16 @@ void *qemu_vmalloc(size_t size)
void *ptr;
size_t align = QEMU_VMALLOC_ALIGN;
- if (size < align) {
+#if defined(CONFIG_VALGRIND)
+ if (running_on_valgrind < 0) {
+ /* First call, test whether we are running on Valgrind.
+ This is a substitute for RUNNING_ON_VALGRIND from valgrind.h. */
+ const char *ld = getenv("LD_PRELOAD");
+ running_on_valgrind = (ld != NULL && strstr(ld, "vgpreload"));
+ }
+#endif
+
+ if (size < align || running_on_valgrind) {
align = getpagesize();
}
ptr = qemu_memalign(align, size);
--
1.7.2.5
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