Re: [PATCH 2/2] qemu: Provide sane default for dump_guest_core

QEMU uses Linux extensions to madvise() to include/exclue guest

memory from core dump. These are obviously not available everywhere. Currently, users have two options: 1) configure <memory dumpCore=''/> in domain XML, or 2) configure dump_guest_core in qemu.conf While these work, they may harm user experience as "things just don't work" out of the box. Provide sane default in virQEMUDriverConfigNew() so neither of two options is required. To have predictable results in tests, explicitly set cfg->dumpGuestCore to false in qemuTestDriverInit() (which creates cfg object for tests). Resolves: https://gitlab.com/libvirt/libvirt/-/issues/679 Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- meson.build | 1 + src/qemu/qemu_conf.c | 11 +++++++++++ tests/testutilsqemu.c | 2 ++ 3 files changed, 14 insertions(+) diff --git a/meson.build b/meson.build index 4c6e5a088e..aa6b8ce5aa 100644 --- a/meson.build +++ b/meson.build @@ -676,6 +676,7 @@ headers = [ 'sched.h', 'sys/auxv.h', 'sys/ioctl.h', + 'sys/mman.h', 'sys/mount.h', 'sys/syscall.h', 'sys/ucred.h', diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c index b36bede6c3..2c4e6a74cb 100644 --- a/src/qemu/qemu_conf.c +++ b/src/qemu/qemu_conf.c @@ -26,6 +26,10 @@ #include <unistd.h> #include <fcntl.h> +#ifdef WITH_SYS_MMAN_H +# include <sys/mman.h> +#endif + #include "virerror.h" #include "qemu_conf.h" #include "qemu_capabilities.h" @@ -287,6 +291,13 @@ virQEMUDriverConfig *virQEMUDriverConfigNew(bool privileged, cfg->deprecationBehavior = g_strdup("none"); cfg->storageUseNbdkit = USE_NBDKIT_DEFAULT; +#ifndef MADV_DONTDUMP + /* QEMU uses Linux extensions to madvise() (MADV_DODUMP/MADV_DONTDUMP) to + * include/exclude guest memory from core dump. These might be unavailable + * on some systems. Provide sane default. */ + cfg->dumpGuestCore = true; +#endif +

return g_steal_pointer(&cfg); } diff --git a/tests/testutilsqemu.c b/tests/testutilsqemu.c index ee6cae218a..4daee432e5 100644 --- a/tests/testutilsqemu.c +++ b/tests/testutilsqemu.c @@ -407,6 +407,8 @@ int qemuTestDriverInit(virQEMUDriver *driver) cfg->hugetlbfs[0].deflt = true; cfg->hugetlbfs[1].size = 1048576; + cfg->dumpGuestCore = false; + driver->privileged = true; return 0; -- 2.44.2