Re: [PATCH v10 4/4] vpci/msix: Free MSIX resources when init_msix() fails

[Jan Beulich <jbeulich@xxxxxxxx>]

On 05.08.2025 05:49, Jiqian Chen wrote:
> When MSI-X initialization fails vPCI will hide the capability, but
> remove of handlers and data won't be performed until the device is
> deassigned.  Introduce a MSI-X cleanup hook that will be called when
> initialization fails to cleanup MSI-X related hooks and free it's
> associated data.
> 
> As all supported capabilities have been switched to use the cleanup
> hooks call those from vpci_deassign_device() instead of open-code the
> capability specific cleanup in there.
> 
> Signed-off-by: Jiqian Chen <Jiqian.Chen@xxxxxxx>
> ---
> cc: "Roger Pau Monné" <roger.pau@xxxxxxxxxx>
> ---
> v9->v10 changes:
> * Call all cleanup hook in vpci_deassign_device() instead of cleanup_msix().

Isn't this rather an omission in an earlier change, and hence may want to
come separately and with a Fixes: tag?

> --- a/xen/drivers/vpci/vpci.c
> +++ b/xen/drivers/vpci/vpci.c
> @@ -321,6 +321,27 @@ void vpci_deassign_device(struct pci_dev *pdev)
>                      &pdev->domain->vpci_dev_assigned_map);
>  #endif
>  
> +    for ( i = 0; i < NUM_VPCI_INIT; i++ )
> +    {
> +        const vpci_capability_t *capability = &__start_vpci_array[i];
> +        const unsigned int cap = capability->id;
> +        unsigned int pos = 0;
> +
> +        if ( !capability->is_ext )
> +            pos = pci_find_cap_offset(pdev->sbdf, cap);
> +        else if ( is_hardware_domain(pdev->domain) )
> +            pos = pci_find_ext_capability(pdev->sbdf, cap);

What's the point of doing this when ...

> +        if ( pos && capability->cleanup )

... ->cleanup is NULL? Don't you want to have

        if ( !capability->cleanup )
            continue;

earlier on?

Jan