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Re: [Xen-devel] HYBRID: PV in HVM container

To: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Subject: Re: [Xen-devel] HYBRID: PV in HVM container
From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Date: Fri, 29 Jul 2011 19:16:39 +0100
Cc: Ian Campbell <Ian.Campbell@xxxxxxxxxxxxx>, "Xen-devel@xxxxxxxxxxxxxxxxxxx" <Xen-devel@xxxxxxxxxxxxxxxxxxx>, Keir Fraser <keir@xxxxxxx>, Stefano Stabellini <Stefano.Stabellini@xxxxxxxxxxxxx>
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On Fri, 29 Jul 2011, Konrad Rzeszutek Wilk wrote:
> On Fri, Jul 29, 2011 at 07:00:07PM +0100, Stefano Stabellini wrote:
> > On Fri, 29 Jul 2011, Konrad Rzeszutek Wilk wrote:
> > > > Besides if we have HVM dom0, we can enable
> > > > XENFEAT_auto_translated_physmap and EPT and have the same level of
> > > > performances of a PV on HVM guest. Moreover since we wouldn't be using
> > > > the mmu pvops anymore we could drop them completely: that would greatly
> > > 
> > > Sure. It also means you MUST have an IOMMU in the box.
> > 
> > Why?
> For HVM dom0s.. But I think when you say HVM here, you mean using
> PV with the hypervisor's code that is used for managing page-tables - 
> So PV+HAP = Stefano's HVM :-)


> > Yes for startup, spinlock, timers and backends. I would use HVM for cpu
> > operations too (no need for pv_cpu_ops.write_gdt_entry anymore for
> > example).
> OK, so a SVM/VMX setup is required.

Yes, I would actually require SVM/VMX for performances and to simplify
the setup and maintenance of the code in general.

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