Re: [RFC PATCH 1/4] xen: Introduce physaddr_abi CDF flag

["Teddy Astie" <teddy.astie@xxxxxxxxxx>]

Le 30/04/2025 à 17:59, Jan Beulich a écrit :
> On 18.04.2025 16:18, Teddy Astie wrote:
>> @@ -745,6 +747,12 @@ static int sanitise_domain_config(struct 
>> xen_domctl_createdomain *config)
>>           return -EINVAL;
>>       }
>>
>> +    if ( physaddr_abi && !hvm )
>> +    {
>> +        dprintk(XENLOG_INFO, "Physical address ABI requested for non-HVM 
>> guest");
>> +        return -EINVAL;
>> +    }

>
> Why this restriction?
>

physaddr_abi changes how copy_from/to_guest works to make it use GPA
instead of GVA. As non-HVM probably means PV guest, it would mean
something like PV guest hypercalls uses physical addresses (derived from
MFN?) instead of virtual addresses, which would not really be practical
for both the guest and the hypervisor.

> Jan
>

Teddy


Teddy Astie | Vates XCP-ng Developer

XCP-ng & Xen Orchestra - Vates solutions

web: https://vates.tech