Re: [PATCH v3 3/3] kvm: call kvm_arch_destroy_vm if vm creation fails

[Sean Christopherson <sean.j.christopherson@intel.com>]

On Thu, Oct 24, 2019 at 04:03:27PM -0700, Jim Mattson wrote:
> From: John Sperbeck <jsperbeck@google.com>
> 
> In kvm_create_vm(), if we've successfully called kvm_arch_init_vm(), but
> then fail later in the function, we need to call kvm_arch_destroy_vm()
> so that it can do any necessary cleanup (like freeing memory).
> 
> Fixes: 44a95dae1d229a ("KVM: x86: Detect and Initialize AVIC support")
> 
> Signed-off-by: John Sperbeck <jsperbeck@google.com>
> Signed-off-by: Jim Mattson <jmattson@google.com>
> Reviewed-by: Junaid Shahid <junaids@google.com>
> ---
>  virt/kvm/kvm_main.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 77819597d7e8e..f8f0106f8d20f 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -649,7 +649,7 @@ static struct kvm *kvm_create_vm(unsigned long type)
>  		struct kvm_memslots *slots = kvm_alloc_memslots();
>  
>  		if (!slots)
> -			goto out_err_no_disable;
> +			goto out_err_no_arch_destroy_vm;
>  		/* Generations must be different for each address space. */
>  		slots->generation = i;
>  		rcu_assign_pointer(kvm->memslots[i], slots);
> @@ -659,12 +659,12 @@ static struct kvm *kvm_create_vm(unsigned long type)
>  		rcu_assign_pointer(kvm->buses[i],
>  			kzalloc(sizeof(struct kvm_io_bus), GFP_KERNEL_ACCOUNT));
>  		if (!kvm->buses[i])
> -			goto out_err_no_disable;
> +			goto out_err_no_arch_destroy_vm;
>  	}
>  
>  	r = kvm_arch_init_vm(kvm, type);
>  	if (r)
> -		goto out_err_no_disable;
> +		goto out_err_no_arch_destroy_vm;
>  
>  	r = hardware_enable_all();
>  	if (r)
> @@ -685,7 +685,7 @@ static struct kvm *kvm_create_vm(unsigned long type)
>  
>  	/*
>  	 * kvm_get_kvm() isn't legal while the vm is being created
> -	 * (e.g. in kvm_arch_init_vm).
> +	 * (e.g. in kvm_arch_init_vm or kvm_arch_destroy_vm).

LOL, even I don't think this one is necessary ;-)

>  	 */
>  	refcount_set(&kvm->users_count, 1);
>  
> @@ -704,6 +704,8 @@ static struct kvm *kvm_create_vm(unsigned long type)
>  out_err_no_srcu:
>  	hardware_disable_all();
>  out_err_no_disable:
> +	kvm_arch_destroy_vm(kvm);
> +out_err_no_arch_destroy_vm:
>  	for (i = 0; i < KVM_NR_BUSES; i++)
>  		kfree(kvm_get_bus(kvm, i));
>  	for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++)
> -- 
> 2.24.0.rc0.303.g954a862665-goog
>