Commit c2a8238a authored by Stefan Weil's avatar Stefan Weil Committed by Anthony Liguori

Support running QEMU on Valgrind

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

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: default avatarStefan Weil <>
Signed-off-by: default avatarAnthony Liguori <>
parent ec38d398
......@@ -36,8 +36,11 @@ extern int daemon(int, int);
#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 QEMU_VMALLOC_ALIGN getpagesize()
......@@ -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;
# define running_on_valgrind 0
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"));
if (size < align || running_on_valgrind) {
align = getpagesize();
ptr = qemu_memalign(align, size);
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