Re: [PATCH v2] x86/kvm: Use RCU for svm_vm_data_hash

[Sairaj Kodilkar <sarunkod@amd.com>]

On 11/11/2026 8:34 PM, Sean Christopherson wrote:
> KVM: SVM:
> 
> "x86/kvm:" is specifically for guest-side code, e.g. arch/x86/kernel/kvm.c
> 
>> Changes since v1:
> 
> In the future, please wait the "normal" amount of time before sending a new
> version, e.g. a day or two for something relatively simple like this.  I.e.
> treat feedback from Sashiko like feedback from a human reviewer, and don't spam
> patches.
> 
> There are times when it's acceptable to break the "don't spam patches" rule, but
> this isn't one of those times.

Hi Sean

Sorry about this, did not mean to spam the patches. I accidently sent
wrong version upstream, thats why decided to respin it. I'll be careful
from next time onwards.

> 
>>  int avic_vcpu_precreate(struct kvm *kvm)
>> @@ -373,9 +373,12 @@ void avic_vm_pre_destroy(struct kvm *kvm)
>>  	if (WARN_ON_ONCE(!enable_apicv) || !kvm_svm->avic_vm_id)
>>  		return;
>>  
>> -	guard(spinlock_irqsave)(&svm_vm_data_hash_lock);
>> +	{
>> +		guard(spinlock_irqsave)(&svm_vm_data_hash_lock);
>> +		hash_del_rcu(&kvm_svm->hnode);
> 
> Eww.  Don't open code scoped_guard(), e.g. this should work:

Ahh right, I missed that.

> 
> 	scoped_guard(spinlock_irqsave, &svm_vm_data_hash_lock)
> 		hash_del(&kvm_svm->hnode);
> 
> 	synchronize_rcu();
> 
> I'm a little hesitant to put a full synchronize_rcu() in the destroy path, but
> in practice it's should be ok.

Thanks
Sairaj