On Tue, Jan 29, Jan Beulich wrote: > >>> On 28.01.13 at 18:44, Stefano Stabellini > >>> <stefano.stabell...@eu.citrix.com> wrote: > > I think that Olaf made his point very clear: a feature A should only be > > enabled if the corresponding flag A is set. > > In fact it seems to me that this patch is correct on its own merits, > > regardless of Xen does or does not. > > > > The Xen tools might or might not know whether a guest is going to be > > Linux, Windows, FreeBSD or whatever else people use nowadays. Setting > > viridian=1 is the safe choice, given that it shouldn't create any > > issues: after all guests are supposed to check for feature flags before > > using them. > > > > If Xen is going to implement "Partition Reference Counter", it is also > > going to set the corresponding flag, so the guest OS (Windows, Linux, > > my pet OS) can check whether the feature is available and decide whether > > it wants to use it. > > While I agree in general, the specific case of the callback vector > seems a little more difficult: As KY says, there's no feature flag > for this (or perhaps more precisely for it being deliverable across > all CPUs), and hence there's both the problem of detection and > the problem of disambiguation (as otherwise both the Hyper-V > code and the Xen code in Linux could be trying to use the same > vector).
This is true, but belongs to that other thread about the interrupt vector. I agree that the detection in ms_hyperv_platform() should be extended, with a DMI check for example. The patch which started this thread is still valid because it enables feature B only if the featurebit for B is enabled. Olaf -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
