Re: [PATCH v2: kvm 4/4] Fix hotplug of CPUs for KVM.

From: Avi Kivity
Date: Tue Sep 29 2009 - 04:30:19 EST


On 09/29/2009 06:04 AM, Zachary Amsden wrote:
Both VMX and SVM require per-cpu memory allocation, which is done at module
init time, for only online cpus.

Backend was not allocating enough structure for all possible CPUs, so
new CPUs coming online could not be hardware enabled.

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index e27b7a9..2cd8bc2 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1716,9 +1716,6 @@ static int kvm_cpu_hotplug(struct notifier_block *notifier, unsigned long val,
{
int cpu = (long)v;

- if (!kvm_usage_count)
- return NOTIFY_OK;
-
val&= ~CPU_TASKS_FROZEN;
switch (val) {
case CPU_DYING:

I still don't see how this bit can work. Maybe if we move the notification registration to the point where kvm_usage_count is bumped.

--
error compiling committee.c: too many arguments to function

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