Re: [PATCH -v2] KVM: fix kvm_coalesced_mmio_init()'s error handling

[Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>]

Wei Yongjun wrote:
> Takuya Yoshikawa wrote:
>> This version may be better.
>>
>> Thanks,
>>   Takuya
>>
>> ===
>> kvm_coalesced_mmio_init() keeps to hold the addresses of a coalesced mmio
>> ring page and dev even after it has freed them.
>>
>> Also, if this function fails, though it must be rare, it seems to be
>> suggesting the system's serious state.
>>
>> This patch changes the error handling for this function to fix these issues.
>>   
> 
> We must also unregister mmu_notifier in the error path.

Oh, sorry.

> 
>> Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
>> ---
>>  virt/kvm/coalesced_mmio.c |    2 ++
>>  virt/kvm/kvm_main.c       |    4 +++-
>>  2 files changed, 5 insertions(+), 1 deletions(-)
>>
>> diff --git a/virt/kvm/coalesced_mmio.c b/virt/kvm/coalesced_mmio.c
>> index 5169736..11776b7 100644
>> --- a/virt/kvm/coalesced_mmio.c
>> +++ b/virt/kvm/coalesced_mmio.c
>> @@ -119,8 +119,10 @@ int kvm_coalesced_mmio_init(struct kvm *kvm)
>>  	return ret;
>>  
>>  out_free_dev:
>> +	kvm->coalesced_mmio_dev = NULL;
>>  	kfree(dev);
>>  out_free_page:
>> +	kvm->coalesced_mmio_ring = NULL;
>>  	__free_page(page);
>>  out_err:
>>  	return ret;
>> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
>> index e758ef7..9e72067 100644
>> --- a/virt/kvm/kvm_main.c
>> +++ b/virt/kvm/kvm_main.c
>> @@ -419,7 +419,9 @@ static struct kvm *kvm_create_vm(void)
>>  	list_add(&kvm->vm_list, &vm_list);
>>  	spin_unlock(&kvm_lock);
>>  #ifdef KVM_COALESCED_MMIO_PAGE_OFFSET
>> -	kvm_coalesced_mmio_init(kvm);
>> +	r = kvm_coalesced_mmio_init(kvm);
>> +	if (r < 0)
>> +		goto out_err;
>>  #endif
>>  out:
>>  	return kvm;
>>