> -----Original Message----- > From: Wei Liu <w...@xen.org> > Sent: 23 September 2019 14:34 > To: Paul Durrant <paul.durr...@citrix.com> > Cc: 'Wei Liu' <w...@xen.org>; Xen Development List > <xen-devel@lists.xenproject.org>; Wei Liu > <li...@microsoft.com>; Andrew Cooper <andrew.coop...@citrix.com>; Michael > Kelley > <mikel...@microsoft.com>; Jan Beulich <jbeul...@suse.com>; Roger Pau Monne > <roger....@citrix.com> > Subject: Re: [Xen-devel] [PATCH for-next RFC 0/8] Port Xen to Hyper-V > > And a bit more thought. > > On Mon, Sep 23, 2019 at 01:54:31PM +0100, Wei Liu wrote: > [...] > > > > > > > > Per TLFS, eVMCS should be used by L1 Xen. > > > > > > Yes, I guess it only needs to be used by L1, but Windows is using an > > > increasing number of VMs for various purposes so I think making it > > > stack well would be useful. > > > > > > > > > > > Not sure what you meant by EPT flush. If you mean things like > > > > HvFlushGuestPhysicalAddressSpace, I think they should be used by Xen > > > > only as well. I'm not sure whether they should be expose to L2 guests. > > > > > > > > > > Yes, that's what I meant and, again, I was thinking about the nested > > > Windows guest using VMs itself. > > > > So this is basically nested on nested. I'm not sure how to make that > > work yet. I'm also not sure how well these interfaces stack. TLFS only > > describes one level of nesting. I will need to ask if we can make nested > > on nested work. > > > > Since L2 Root is Windows in a Hyper-V setup, chances are what you want > already works. Of course this depends on whether Windows, when running > as Root or Child, uses VM related features. > > I'm not versed in Windows features. If you have specific things in mind, > I can ask for more details and think about how to implement them in Xen.
Well, eVMCS would be a major one. If the L2 Windows could be told to use that rather than L0 have to bounce individual VMREAD/VMWRITEs up to L1 then that would be a win. Paul > > Wei. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
