On 12.10.2021 23:48, Stefano Stabellini wrote: > On Mon, 11 Oct 2021, Roger Pau Monné wrote: >> On Wed, Oct 06, 2021 at 06:40:33PM +0100, Rahul Singh wrote: >>> Introduce XEN_DOMCTL_CDF_vpci flag to enable VPCI support in XEN. >>> Reject the use of this new flag for x86 as VPCI is not supported for >>> DOMU guests for x86. >> >> I don't like this approach, XEN_DOMCTL_CDF_vpci should be set for x86 >> PVH dom0, like we do for any other CDF flags when Xen builds dom0. >> >> Things like PVH vs PV get translated into CDF flags by create_dom0, >> and processed normally by the sanitise_domain_config logic, vPCI >> should be handled that way. >> >> Do you think you could see about fixing this? > > Andrew suggested to use XEN_SYSCTL_PHYSCAP_vpci to check whether we can > set XEN_DOMCTL_CDF_vpci in libxl and it looks like we have consensus on > this approach. [1][2] > > So it makes sense that XEN_DOMCTL_CDF_vpci is only set when > XEN_SYSCTL_PHYSCAP_vpci is also set, i.e. XEN_SYSCTL_PHYSCAP_vpci == > XEN_DOMCTL_CDF_vpci. > > From [2], XEN_SYSCTL_PHYSCAP_vpci is not going to be set on x86, so then > XEN_DOMCTL_CDF_vpci should also be left unset? > > If you think XEN_DOMCTL_CDF_vpci should be set for x86 PVH Dom0, then > XEN_SYSCTL_PHYSCAP_vpci should also be set for x86 PVH Dom0.
Except that XEN_SYSCTL_PHYSCAP_vpci is not a domain specific attribute, but a host-wide one. Jan
