Re: [PATCH v7] vpci: Add resizable bar support

[Jan Beulich <jbeulich@xxxxxxxx>]

On 06.02.2025 18:17, Roger Pau Monné wrote:
> On Thu, Feb 06, 2025 at 05:39:00PM +0800, Jiqian Chen wrote:
>> +        rc = vpci_add_register(pdev->vpci, vpci_hw_read32, rebar_ctrl_write,
>> +                               rebar_offset + PCI_REBAR_CTRL(i), 4, bar);
>> +        if ( rc )
>> +        {
>> +            printk(XENLOG_ERR "%pd %pp: BAR%u fail to add reg of REBAR_CTRL 
>> rc=%d\n",
>> +                   pdev->domain, &pdev->sbdf, index, rc);
>> +            /*
>> +             * Ideally we would hide the ReBar capability here, but code
>> +             * for doing so still needs to be written. And using continue
>> +             * can keep any possible hooks working, instead, returning
>> +             * failure would cause all vPCI hooks down and hardware domain
>> +             * has entirely unmediated access to the device, which is worse.
>> +             */
> 
> "Ideally we would hide the ReBar capability on error, but code for
> doing so still needs to be written. Use continue instead to keep any
> already setup register hooks, as returning an error will cause
> the hardware domain to get unmediated access to all device registers."
> 
> Seems slightly easier to parse IMO (again I'm not a native speaker, so
> your proposed comment might be better).

+1

Jan