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[RFC PATCH 7/9] cpus: Only expose REALIZED vCPUs to global &cpus_queue
From: |
Philippe Mathieu-Daudé |
Subject: |
[RFC PATCH 7/9] cpus: Only expose REALIZED vCPUs to global &cpus_queue |
Date: |
Tue, 28 Jan 2025 15:21:50 +0100 |
cpu_list_add() was doing 2 distinct things:
- assign some index to vCPU
- add unrealized (thus in inconsistent state) vcpu to &cpus_queue
Code using CPU_FOREACH() macro would iterate over possibly
unrealized vCPUs, often dealt with special casing.
In order to avoid that, we move the addition of vCPU to global queue
to the DeviceWire handler, which is called just before switching the
vCPU to REALIZED state. This ensure all &cpus_queue users (like via
&first_cpu or CPU_FOREACH) get a realized vCPU in consistent state.
Similarly we remove it from the global queue at DeviceUnwire phase,
just after marking the vCPU UNREALIZED.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
cpu-common.c | 2 --
hw/core/cpu-common.c | 5 +++++
2 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/cpu-common.c b/cpu-common.c
index 4248b2d727e..72ee8dc414e 100644
--- a/cpu-common.c
+++ b/cpu-common.c
@@ -91,7 +91,6 @@ void cpu_list_add(CPUState *cpu)
} else {
assert(!cpu_index_auto_assigned);
}
- QTAILQ_INSERT_TAIL_RCU(&cpus_queue, cpu, node);
cpu_list_generation_id++;
}
@@ -103,7 +102,6 @@ void cpu_list_remove(CPUState *cpu)
return;
}
- QTAILQ_REMOVE_RCU(&cpus_queue, cpu, node);
cpu->cpu_index = UNASSIGNED_CPU_INDEX;
cpu_list_generation_id++;
}
diff --git a/hw/core/cpu-common.c b/hw/core/cpu-common.c
index 8a02ac146f6..df7a6913603 100644
--- a/hw/core/cpu-common.c
+++ b/hw/core/cpu-common.c
@@ -218,6 +218,8 @@ static void cpu_common_wire(DeviceState *dev)
{
CPUState *cpu = CPU(dev);
+ QTAILQ_INSERT_TAIL_RCU(&cpus_queue, cpu, node);
+
if (dev->hotplugged) {
cpu_synchronize_post_init(cpu);
cpu_resume(cpu);
@@ -226,6 +228,9 @@ static void cpu_common_wire(DeviceState *dev)
static void cpu_common_unwire(DeviceState *dev)
{
+ CPUState *cpu = CPU(dev);
+
+ QTAILQ_REMOVE_RCU(&cpus_queue, cpu, node);
}
static void cpu_common_unrealizefn(DeviceState *dev)
--
2.47.1
- [RFC PATCH 2/9] accel/tcg: Invalidate TB jump cache with global vCPU queue locked, (continued)
- [RFC PATCH 2/9] accel/tcg: Invalidate TB jump cache with global vCPU queue locked, Philippe Mathieu-Daudé, 2025/01/28
- [RFC PATCH 3/9] cpus: Remove cpu from global queue after UNREALIZE completed, Philippe Mathieu-Daudé, 2025/01/28
- [RFC PATCH 4/9] hw/qdev: Introduce DeviceClass::[un]wire() handlers, Philippe Mathieu-Daudé, 2025/01/28
- [PATCH 5/9] cpus: Add DeviceClass::[un]wire() stubs, Philippe Mathieu-Daudé, 2025/01/28
- [PATCH 6/9] cpus: Call hotplug handlers in DeviceWire(), Philippe Mathieu-Daudé, 2025/01/28
- [RFC PATCH 7/9] cpus: Only expose REALIZED vCPUs to global &cpus_queue,
Philippe Mathieu-Daudé <=
- [PATCH 8/9] accel/kvm: Assert vCPU is created when calling kvm_dirty_ring_reap*(), Philippe Mathieu-Daudé, 2025/01/28
- [PATCH 9/9] accel/kvm: Remove unreachable assertion in kvm_dirty_ring_reap*(), Philippe Mathieu-Daudé, 2025/01/28