Chris Lalancette wrote: > On 01/04/11 - 10:41:07AM, Jim Fehlig wrote: > >> I'm looking into a bug where a libvirt-created xen HVM guest boots >> *very* slowly on an EPT-enabled machine, particularly when the guest has >> a dedicated PCI device. >> >> xen-unstable c/s 16931 [1] introduced a per-guest HAP (hardware assisted >> paging) setting. Unfortunately, the sane default of hap=1 is done by xm >> client tool instead of xend, so an HVM guest created with xm tool >> (hap=1) boots as expected but takes much longer when created through >> libvirt (hap=0). >> >> Should libvirt expose this feature in domain XML? Should it be possible >> to enable/disable hardware assisted paging on a per-guest level with >> libvirt? If so, where does such a setting belong? It seems analogous >> to enabling/disabling PAE and as such belongs under hypervisor >> features. On IRC, Eric suggested it might fall under memoryBacking like >> huge page support in KVM. >> >> If folks feel this setting should not be exposed, it could be >> unconditionally set in the xen driver for HVM guests, similar to the way >> usb setting is currently handled (see attached patch). Note that the >> xen domain builder will ignore this setting on hardware without the feature. >> > > My personal feeling is that this is something we should expose. It is useful > for testing sometimes, so I think that we could expose it under the hypervisor > features with apic, acpi, etc like you suggest. > I sent a small patch set to the list which adds HAP to hypervisor features https://www.redhat.com/archives/libvir-list/2011-January/msg00157.html > However, I would caution you to beware adding the hap flag unconditionally. > Right. The patches just expose the setting - users must specify it. Could you review those? :) Thanks! Jim -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list