Re: [Xen-devel] [PATCH SERIES] enhanced PV on Xen HVM

From: Stefano Stabellini
Date: Tue Mar 02 2010 - 13:37:45 EST

On Tue, 2 Mar 2010, Stefano Stabellini wrote:
> Hi all,
> this patch series is derived from an earlier version of Shen's "PV
> extension of HVM" patch series.
> It tries to achieve two goals:
> - enable PV devices in Linux running in a Xen HVM domain;
> - receive evtchns in place of interrupts to avoid expensive EOIs.
> The main difference between the two patch series is the way the second
> goals is achieved: in this patch series I am trying to reuse the same
> code that is used in the Linux kernel to setup GSI to pirq mappings when
> running as dom0.
> In this case the GSIs that are being remapped correspond to emulated
> interrupts, but Xen knows the difference and handles the two cases
> separately.
> It should be easy to use this mechanism also to map interrupts or MSIs
> from pci passthrough devices with minimal changes to the Linux kernel.
> The patch series consists of 5 patches, 1 for Xen and 4 for Linux; each
> patch comes with a detailed description.
> Any comment, critic or suggestion is very welcome.

I should point out that the Linux side of the patch series is developed
against the branch "xen/dom0/apic-xiantao" of the pvops tree, that is
the master branch plus the recent apic rework.
Moreover it still needs few fixes: in particular the PV on HVM SMP
initialization code is exactly the same as in the last patch series from
Shen, therefore it doesn't address any of Jeremy's comments yet.

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