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[8/9] accel/kvm: Assert vCPU is created when calling kvm_dirty_ring_reap*()

Message ID 20250128142152.9889-9-philmd@linaro.org
State New
Headers show
Series accel: Only include qdev-realized vCPUs in global &cpus_queue | expand

Commit Message

Philippe Mathieu-Daudé Jan. 28, 2025, 2:21 p.m. UTC 
Previous commits made sure vCPUs are realized before accelerators
(such KVM) use them. Ensure that by asserting the vCPU is created,
no need to return.

For more context, see commit 56adee407fc ("kvm: dirty-ring: Fix race
with vcpu creation").

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 accel/kvm/kvm-all.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

Comments

Richard Henderson Jan. 28, 2025, 8:57 p.m. UTC | #1 
On 1/28/25 06:21, Philippe Mathieu-Daudé wrote:
> Previous commits made sure vCPUs are realized before accelerators
> (such KVM) use them. Ensure that by asserting the vCPU is created,
> no need to return.
> 
> For more context, see commit 56adee407fc ("kvm: dirty-ring: Fix race
> with vcpu creation").
> 
> Signed-off-by: Philippe Mathieu-Daudé<philmd@linaro.org>
> ---
>   accel/kvm/kvm-all.c | 8 +++-----
>   1 file changed, 3 insertions(+), 5 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~
diff mbox series

Patch

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index c65b790433c..cb56d120a91 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -831,13 +831,11 @@  static uint32_t kvm_dirty_ring_reap_one(KVMState *s, CPUState *cpu)
     uint32_t count = 0, fetch = cpu->kvm_fetch_index;
 
     /*
-     * It's possible that we race with vcpu creation code where the vcpu is
+     * It's not possible that we race with vcpu creation code where the vcpu is
      * put onto the vcpus list but not yet initialized the dirty ring
-     * structures.  If so, skip it.
+     * structures.
      */
-    if (!cpu->created) {
-        return 0;
-    }
+    assert(cpu->created);
 
     assert(dirty_gfns && ring_size);
     trace_kvm_dirty_ring_reap_vcpu(cpu->cpu_index);