diff mbox

[v2:,4/4] Fix hotplug of CPUs for KVM.

Message ID 1254197072-889-5-git-send-email-zamsden@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Zachary Amsden Sept. 29, 2009, 4:04 a.m. UTC
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.

Signed-off-by: Zachary Amsden <zamsden@redhat.com>
---
 arch/x86/kvm/svm.c  |    4 ++--
 arch/x86/kvm/vmx.c  |    6 ++++--
 virt/kvm/kvm_main.c |    3 ---
 3 files changed, 6 insertions(+), 7 deletions(-)

Comments

Avi Kivity Sept. 29, 2009, 8:30 a.m. UTC | #1
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.
Zachary Amsden Sept. 29, 2009, 3:51 p.m. UTC | #2
On 09/28/2009 10:30 PM, Avi Kivity wrote:
> 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.

That was stray junk in the patch.  Let me rediff...

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diff mbox

Patch

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index d1036ce..02a4269 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -482,7 +482,7 @@  static __init int svm_hardware_setup(void)
 		kvm_enable_efer_bits(EFER_SVME);
 	}
 
-	for_each_online_cpu(cpu) {
+	for_each_possible_cpu(cpu) {
 		r = svm_cpu_init(cpu);
 		if (r)
 			goto err;
@@ -516,7 +516,7 @@  static __exit void svm_hardware_unsetup(void)
 {
 	int cpu;
 
-	for_each_online_cpu(cpu)
+	for_each_possible_cpu(cpu)
 		svm_cpu_uninit(cpu);
 
 	__free_pages(pfn_to_page(iopm_base >> PAGE_SHIFT), IOPM_ALLOC_ORDER);
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 3fe0d42..e86f1a6 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1350,15 +1350,17 @@  static void free_kvm_area(void)
 {
 	int cpu;
 
-	for_each_online_cpu(cpu)
+	for_each_possible_cpu(cpu) {
 		free_vmcs(per_cpu(vmxarea, cpu));
+		per_cpu(vmxarea, cpu) = NULL;
+	}
 }
 
 static __init int alloc_kvm_area(void)
 {
 	int cpu;
 
-	for_each_online_cpu(cpu) {
+	for_each_possible_cpu(cpu) {
 		struct vmcs *vmcs;
 
 		vmcs = alloc_vmcs_cpu(cpu);
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: