summaryrefslogtreecommitdiffstats
path: root/include/qom
diff options
context:
space:
mode:
authorEmilio G. Cota2018-08-19 11:13:35 +0200
committerPaolo Bonzini2018-08-23 18:46:25 +0200
commit068a5ea02f62853116788a2c42d8851a94bb7567 (patch)
tree0e7c635241a440b1aeee6dd853077fad928a40d4 /include/qom
parentspapr: do not use CPU_FOREACH_REVERSE (diff)
downloadqemu-068a5ea02f62853116788a2c42d8851a94bb7567.tar.gz
qemu-068a5ea02f62853116788a2c42d8851a94bb7567.tar.xz
qemu-068a5ea02f62853116788a2c42d8851a94bb7567.zip
qom: convert the CPU list to RCU
Iterating over the list without using atomics is undefined behaviour, since the list can be modified concurrently by other threads (e.g. every time a new thread is created in user-mode). Fix it by implementing the CPU list as an RCU QTAILQ. This requires a little bit of extra work to traverse list in reverse order (see previous patch), but other than that the conversion is trivial. Signed-off-by: Emilio G. Cota <cota@braap.org> Message-Id: <20180819091335.22863-12-cota@braap.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'include/qom')
-rw-r--r--include/qom/cpu.h11
1 files changed, 5 insertions, 6 deletions
diff --git a/include/qom/cpu.h b/include/qom/cpu.h
index ecf6ed556a..dc130cd307 100644
--- a/include/qom/cpu.h
+++ b/include/qom/cpu.h
@@ -26,6 +26,7 @@
#include "exec/memattrs.h"
#include "qapi/qapi-types-run-state.h"
#include "qemu/bitmap.h"
+#include "qemu/rcu_queue.h"
#include "qemu/queue.h"
#include "qemu/thread.h"
@@ -442,13 +443,11 @@ struct CPUState {
QTAILQ_HEAD(CPUTailQ, CPUState);
extern struct CPUTailQ cpus;
-#define CPU_NEXT(cpu) QTAILQ_NEXT(cpu, node)
-#define CPU_FOREACH(cpu) QTAILQ_FOREACH(cpu, &cpus, node)
+#define first_cpu QTAILQ_FIRST_RCU(&cpus)
+#define CPU_NEXT(cpu) QTAILQ_NEXT_RCU(cpu, node)
+#define CPU_FOREACH(cpu) QTAILQ_FOREACH_RCU(cpu, &cpus, node)
#define CPU_FOREACH_SAFE(cpu, next_cpu) \
- QTAILQ_FOREACH_SAFE(cpu, &cpus, node, next_cpu)
-#define CPU_FOREACH_REVERSE(cpu) \
- QTAILQ_FOREACH_REVERSE(cpu, &cpus, CPUTailQ, node)
-#define first_cpu QTAILQ_FIRST(&cpus)
+ QTAILQ_FOREACH_SAFE_RCU(cpu, &cpus, node, next_cpu)
extern __thread CPUState *current_cpu;