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[Qemu-devel] [PATCH v5 3/7] trace: [tcg] Delay changes to dynamic state
From: |
Lluís Vilanova |
Subject: |
[Qemu-devel] [PATCH v5 3/7] trace: [tcg] Delay changes to dynamic state when translating |
Date: |
Wed, 28 Dec 2016 15:07:58 +0100 |
User-agent: |
StGit/0.17.1-dirty |
This keeps consistency across all decisions taken during translation
when the dynamic state of a vCPU is changed in the middle of translating
some guest code.
Signed-off-by: Lluís Vilanova <address@hidden>
---
cpu-exec.c | 26 ++++++++++++++++++++++++++
include/qom/cpu.h | 7 +++++++
qom/cpu.c | 4 ++++
trace/control-target.c | 11 +++++++++--
4 files changed, 46 insertions(+), 2 deletions(-)
diff --git a/cpu-exec.c b/cpu-exec.c
index 4188fed3c6..1b7366efb0 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -33,6 +33,7 @@
#include "hw/i386/apic.h"
#endif
#include "sysemu/replay.h"
+#include "trace/control.h"
/* -icount align implementation. */
@@ -451,9 +452,21 @@ static inline bool cpu_handle_exception(CPUState *cpu, int
*ret)
#ifndef CONFIG_USER_ONLY
} else if (replay_has_exception()
&& cpu->icount_decr.u16.low + cpu->icount_extra == 0) {
+ /* delay changes to this vCPU's dstate during translation */
+ atomic_set(&cpu->trace_dstate_delayed_req, false);
+ atomic_set(&cpu->trace_dstate_must_delay, true);
+
/* try to cause an exception pending in the log */
cpu_exec_nocache(cpu, 1, tb_find(cpu, NULL, 0), true);
*ret = -1;
+
+ /* apply and disable delayed dstate changes */
+ atomic_set(&cpu->trace_dstate_must_delay, false);
+ if (unlikely(atomic_read(&cpu->trace_dstate_delayed_req))) {
+ bitmap_copy(cpu->trace_dstate, cpu->trace_dstate_delayed,
+ trace_get_vcpu_event_count());
+ }
+
return true;
#endif
}
@@ -634,8 +647,21 @@ int cpu_exec(CPUState *cpu)
for(;;) {
cpu_handle_interrupt(cpu, &last_tb);
+
+ /* delay changes to this vCPU's dstate during translation */
+ atomic_set(&cpu->trace_dstate_delayed_req, false);
+ atomic_set(&cpu->trace_dstate_must_delay, true);
+
tb = tb_find(cpu, last_tb, tb_exit);
cpu_loop_exec_tb(cpu, tb, &last_tb, &tb_exit, &sc);
+
+ /* apply and disable delayed dstate changes */
+ atomic_set(&cpu->trace_dstate_must_delay, false);
+ if (unlikely(atomic_read(&cpu->trace_dstate_delayed_req))) {
+ bitmap_copy(cpu->trace_dstate, cpu->trace_dstate_delayed,
+ trace_get_vcpu_event_count());
+ }
+
/* Try to align the host and virtual clocks
if the guest is in advance */
align_clocks(&sc, cpu);
diff --git a/include/qom/cpu.h b/include/qom/cpu.h
index 3f79a8e955..58255d06fa 100644
--- a/include/qom/cpu.h
+++ b/include/qom/cpu.h
@@ -295,6 +295,10 @@ struct qemu_work_item;
* @kvm_fd: vCPU file descriptor for KVM.
* @work_mutex: Lock to prevent multiple access to queued_work_*.
* @queued_work_first: First asynchronous work pending.
+ * @trace_dstate_must_delay: Whether a change to trace_dstate must be delayed.
+ * @trace_dstate_delayed_req: Whether a change to trace_dstate was delayed.
+ * @trace_dstate_delayed: Delayed changes to trace_dstate (includes all changes
+ * to @trace_dstate).
* @trace_dstate: Dynamic tracing state of events for this vCPU (bitmask).
*
* State of one CPU core or thread.
@@ -370,6 +374,9 @@ struct CPUState {
* Dynamically allocated based on bitmap requried to hold up to
* trace_get_vcpu_event_count() entries.
*/
+ bool trace_dstate_must_delay;
+ bool trace_dstate_delayed_req;
+ unsigned long *trace_dstate_delayed;
unsigned long *trace_dstate;
/* TODO Move common fields from CPUArchState here. */
diff --git a/qom/cpu.c b/qom/cpu.c
index 03d9190f8c..d56496d28d 100644
--- a/qom/cpu.c
+++ b/qom/cpu.c
@@ -367,6 +367,9 @@ static void cpu_common_initfn(Object *obj)
QTAILQ_INIT(&cpu->breakpoints);
QTAILQ_INIT(&cpu->watchpoints);
+ cpu->trace_dstate_must_delay = false;
+ cpu->trace_dstate_delayed_req = false;
+ cpu->trace_dstate_delayed = bitmap_new(trace_get_vcpu_event_count());
cpu->trace_dstate = bitmap_new(trace_get_vcpu_event_count());
cpu_exec_initfn(cpu);
@@ -375,6 +378,7 @@ static void cpu_common_initfn(Object *obj)
static void cpu_common_finalize(Object *obj)
{
CPUState *cpu = CPU(obj);
+ g_free(cpu->trace_dstate_delayed);
g_free(cpu->trace_dstate);
}
diff --git a/trace/control-target.c b/trace/control-target.c
index 7ebf6e0bcb..aba8db55de 100644
--- a/trace/control-target.c
+++ b/trace/control-target.c
@@ -69,13 +69,20 @@ void trace_event_set_vcpu_state_dynamic(CPUState *vcpu,
if (state_pre != state) {
if (state) {
trace_events_enabled_count++;
- set_bit(vcpu_id, vcpu->trace_dstate);
+ set_bit(vcpu_id, vcpu->trace_dstate_delayed);
+ if (!atomic_read(&vcpu->trace_dstate_must_delay)) {
+ set_bit(vcpu_id, vcpu->trace_dstate);
+ }
(*ev->dstate)++;
} else {
trace_events_enabled_count--;
- clear_bit(vcpu_id, vcpu->trace_dstate);
+ clear_bit(vcpu_id, vcpu->trace_dstate_delayed);
+ if (!atomic_read(&vcpu->trace_dstate_must_delay)) {
+ clear_bit(vcpu_id, vcpu->trace_dstate);
+ }
(*ev->dstate)--;
}
+ atomic_set(&vcpu->trace_dstate_delayed_req, true);
}
}
- [Qemu-devel] [PATCH v5 0/7] trace: [tcg] Optimize per-vCPU tracing states with separate TB caches, Lluís Vilanova, 2016/12/28
- [Qemu-devel] [PATCH v5 1/7] exec: [tcg] Refactor flush of per-CPU virtual TB cache, Lluís Vilanova, 2016/12/28
- [Qemu-devel] [PATCH v5 2/7] trace: Make trace_get_vcpu_event_count() inlinable, Lluís Vilanova, 2016/12/28
- [Qemu-devel] [PATCH v5 3/7] trace: [tcg] Delay changes to dynamic state when translating,
Lluís Vilanova <=
- [Qemu-devel] [PATCH v5 4/7] exec: [tcg] Use different TBs according to the vCPU's dynamic tracing state, Lluís Vilanova, 2016/12/28
- [Qemu-devel] [PATCH v5 5/7] trace: [tcg] Do not generate TCG code to trace dinamically-disabled events, Lluís Vilanova, 2016/12/28
- [Qemu-devel] [PATCH v5 6/7] trace: [tcg, trivial] Re-align generated code, Lluís Vilanova, 2016/12/28
- [Qemu-devel] [PATCH v5 7/7] trace: [trivial] Statically enable all guest events, Lluís Vilanova, 2016/12/28