On 2025/6/18 22:45, Jan Beulich wrote:
> On 12.06.2025 11:29, Jiqian Chen wrote:
>> --- a/xen/drivers/vpci/msi.c
>> +++ b/xen/drivers/vpci/msi.c
>> @@ -193,6 +193,33 @@ static void cf_check mask_write(
>> msi->mask = val;
>> }
>>
>> +static int cf_check cleanup_msi(struct pci_dev *pdev)
>> +{
>> + int rc;
>> + unsigned int end, size;
>> + struct vpci *vpci = pdev->vpci;
>> + const unsigned int msi_pos = pdev->msi_pos;
>> + const unsigned int ctrl = msi_control_reg(msi_pos);
>> +
>> + if ( !msi_pos || !vpci->msi )
>> + return 0;
>> +
>> + if ( vpci->msi->masking )
>> + end = msi_pending_bits_reg(msi_pos, vpci->msi->address64);
>> + else
>> + end = msi_mask_bits_reg(msi_pos, vpci->msi->address64) - 2;
>> +
>> + size = end - ctrl;
>> +
>> + rc = vpci_remove_registers(vpci, ctrl, size);
>> + if ( rc )
>> + return rc;
>
> This is a difficult one: It's not a good idea to simply return here, yet
> at the same time the handling of the register we're unable to remove may
> still require e.g. ...
>
>> + XFREE(vpci->msi);
>
> ... this. There may therefore be more work required, such that in the
> end we're able to ...
>
>> + return vpci_add_register(pdev->vpci, vpci_hw_read16, NULL, ctrl, 2,
>> NULL);
>
> ... try this at least on a best effort basis.
>
> More generally: I don't think failure here (or in other .cleanup hook
> functions) may go entirely silently.
Does below meet your modification expectations?
rc = vpci_remove_registers(vpci, ctrl, size);
if ( rc )
printk(XENLOG_ERR "%pd %pp: remove msi handlers fail rc=%d\n",
pdev->domain, &pdev->sbdf, rc);
XFREE(vpci->msi);
/*
* The driver may not traverse the capability list and think device
* supports MSI by default. So here let the control register of MSI
* be Read-Only is to ensure MSI disabled.
*/
rc = vpci_add_register(vpci, vpci_hw_read16, NULL, ctrl, 2, NULL);
if ( rc )
printk(XENLOG_ERR "%pd %pp: add dummy msi ctrl handler fail rc=%d\n",
pdev->domain, &pdev->sbdf, rc);
return rc;
>
> Jan
--
Best regards,
Jiqian Chen.
