From a028edeaa6f1c154f06e16440e46b0f876a64077 Mon Sep 17 00:00:00 2001 From: Alexander Bulekov Date: Wed, 19 Feb 2020 23:11:09 -0500 Subject: [PATCH] exec: keep ram block across fork when using qtest Ram blocks were marked MADV_DONTFORK breaking fuzzing-tests which execute each test-input in a forked process. Signed-off-by: Alexander Bulekov Reviewed-by: Stefan Hajnoczi Reviewed-by: Darren Kenny Message-id: 20200220041118.23264-14-alxndr@bu.edu Signed-off-by: Stefan Hajnoczi --- exec.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/exec.c b/exec.c index 8e9cc3b47c..c930040f83 100644 --- a/exec.c +++ b/exec.c @@ -35,6 +35,7 @@ #include "sysemu/kvm.h" #include "sysemu/sysemu.h" #include "sysemu/tcg.h" +#include "sysemu/qtest.h" #include "qemu/timer.h" #include "qemu/config-file.h" #include "qemu/error-report.h" @@ -2305,8 +2306,15 @@ static void ram_block_add(RAMBlock *new_block, Error **errp, bool shared) if (new_block->host) { qemu_ram_setup_dump(new_block->host, new_block->max_length); qemu_madvise(new_block->host, new_block->max_length, QEMU_MADV_HUGEPAGE); - /* MADV_DONTFORK is also needed by KVM in absence of synchronous MMU */ - qemu_madvise(new_block->host, new_block->max_length, QEMU_MADV_DONTFORK); + /* + * MADV_DONTFORK is also needed by KVM in absence of synchronous MMU + * Configure it unless the machine is a qtest server, in which case + * KVM is not used and it may be forked (eg for fuzzing purposes). + */ + if (!qtest_enabled()) { + qemu_madvise(new_block->host, new_block->max_length, + QEMU_MADV_DONTFORK); + } ram_block_notify_add(new_block->host, new_block->max_length); } } -- 2.11.4.GIT