Re: [PATCH v4 3/6] KVM: s390: pci: Fix missing error codes and memory unaccounting

[Matthew Rosato <mjrosato@linux.ibm.com>]

On 7/22/26 1:06 PM, Farhan Ali wrote:
> In kvm_s390_pci_aif_enable() two error paths failed to set error code,

nit: set 'an' error code

> causing the function to return 0 on failure. It also failed to rollback
> memory accounting on failure. Fix both by propagating error code on

'an' error code

> failure and calling unaccount_mem() in the cleanup path.

With or without those changes:

Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>

> 
> Fixes: 3c5a1b6f0a18 ("KVM: s390: pci: provide routines for enabling/disabling interrupt forwarding")
> Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
> ---
>  arch/s390/kvm/pci.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
> index 1b3114c7cfbb..33abc15aa685 100644
> --- a/arch/s390/kvm/pci.c
> +++ b/arch/s390/kvm/pci.c
> @@ -297,14 +297,17 @@ static int kvm_s390_pci_aif_enable(struct zpci_dev *zdev, struct zpci_fib *fib,
>  	}
>  
>  	/* Account for pinned pages, roll back on failure */
> -	if (account_mem(zdev->kzdev, pcount))
> +	rc = account_mem(zdev->kzdev, pcount);
> +	if (rc)
>  		goto unpin2;
>  
>  	/* AISB must be allocated before we can fill in GAITE */
>  	mutex_lock(&aift->aift_lock);
>  	bit = airq_iv_alloc_bit(aift->sbv);
> -	if (bit == -1UL)
> +	if (bit == -1UL) {
> +		rc = -ENOMEM;
>  		goto unlock;
> +	}
>  	zdev->aisb = bit; /* store the summary bit number */
>  	zdev->aibv = airq_iv_create(msi_vecs, AIRQ_IV_DATA |
>  				    AIRQ_IV_BITLOCK |
> @@ -348,6 +351,8 @@ static int kvm_s390_pci_aif_enable(struct zpci_dev *zdev, struct zpci_fib *fib,
>  	return rc;
>  
>  unlock:
> +	if (pcount > 0)
> +		unaccount_mem(zdev->kzdev, pcount);
>  	mutex_unlock(&aift->aift_lock);
>  unpin2:
>  	if (fib->fmt0.sum == 1)