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

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
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: default avatarStefan Weil <sw@weilnetz.de>
Signed-off-by: default avatarAnthony Liguori <aliguori@us.ibm.com>
parent ec38d398

oslib-posix.c

+19 −3
Original line number Diff line number Diff line
@@ -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);