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

["Chen, Jiqian" <Jiqian.Chen@xxxxxxx>]

On 2025/8/5 16:43, Jan Beulich wrote:
> On 05.08.2025 05:49, Jiqian Chen wrote:
>> --- a/xen/drivers/vpci/msix.c
>> +++ b/xen/drivers/vpci/msix.c
>> @@ -655,6 +655,48 @@ int vpci_make_msix_hole(const struct pci_dev *pdev)
>>      return 0;
>>  }
>>  
>> +static int cf_check cleanup_msix(const struct pci_dev *pdev)
>> +{
>> +    int rc;
>> +    struct vpci *vpci = pdev->vpci;
>> +    const unsigned int msix_pos = pdev->msix_pos;
>> +
>> +    if ( !msix_pos )
>> +        return 0;
>> +
>> +    rc = vpci_remove_registers(vpci, msix_control_reg(msix_pos), 2);
>> +    if ( rc )
>> +    {
>> +        printk(XENLOG_ERR "%pd %pp: fail to remove MSIX handlers rc=%d\n",
>> +               pdev->domain, &pdev->sbdf, rc);
>> +        ASSERT_UNREACHABLE();
>> +        return rc;
>> +    }
>> +
>> +    if ( vpci->msix )
>> +    {
>> +        list_del(&vpci->msix->next);
>> +        for ( unsigned int i = 0; i < ARRAY_SIZE(vpci->msix->table); i++ )
>> +            if ( vpci->msix->table[i] )
>> +                iounmap(vpci->msix->table[i]);
>> +
>> +        XFREE(vpci->msix);
>> +    }
>> +
>> +    /*
>> +     * The driver may not traverse the capability list and think device
>> +     * supports MSIX by default. So here let the control register of MSIX
>> +     * be Read-Only is to ensure MSIX disabled.
>> +     */
>> +    rc = vpci_add_register(vpci, vpci_hw_read16, NULL,
>> +                           msix_control_reg(msix_pos), 2, NULL);
>> +    if ( rc )
>> +        printk(XENLOG_ERR "%pd %pp: fail to add MSIX ctrl handler rc=%d\n",
>> +               pdev->domain, &pdev->sbdf, rc);
> 
> Here as well as for MSI: Wouldn't this better be limited to the init-failure
> case? No point in adding a register hook (and possibly emitting a misleading
> log message) when we're tearing down anyway. IOW I think the ->cleanup()
> hook needs a boolean parameter, unless the distinction of the two cases can
> be (reliably) inferred from some other property.
To make these changes, can I add a new patch as the last patch of this series?
And the new patch will do:
1. add a boolean parameter for cleanup hook to separate whose calls 
cleanup(during initialization or during deassign device).
2. call all cleanup hooks in vpci_deassign_device().
3. remove the MSI/MSIX specific free actions in vpci_deassign_device().

> 
>> --- 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);
>> +
>> +        if ( pos && capability->cleanup )
>> +        {
>> +            int rc = capability->cleanup(pdev);
>> +            if ( rc )
>> +                printk(XENLOG_ERR "%pd %pp: clean %s cap %u fail rc=%d\n",
>> +                       pdev->domain, &pdev->sbdf,
>> +                       capability->is_ext ? "extended" : "legacy", cap, rc);
>> +        }
>> +    }
> 
> With this imo the patch subject is now wrong, too.
> 
> Jan

-- 
Best regards,
Jiqian Chen.