Re: [PATCH RESEND qemu-xen-traditional] xen/pt: allow QEMU to request MSI unmasking at bind time

From: "Pasi Kärkkäinen" <pasik@iki.fi>
To: "Paraschiv, Andra-Irina" <andraprs@amazon.com>
Cc: "sstabellini@kernel.org" <sstabellini@kernel.org>,
	"andrew.cooper3@citrix.com" <andrew.cooper3@citrix.com>,
	"jbeulich@suse.com" <jbeulich@suse.com>,
	"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
	Ian Jackson <ian.jackson@citrix.com>,
	"Woodhouse, David" <dwmw@amazon.co.uk>,
	"roger.pau@citrix.com" <roger.pau@citrix.com>
Subject: Re: [PATCH RESEND qemu-xen-traditional] xen/pt: allow QEMU to request MSI unmasking at bind time
Date: Tue, 30 Oct 2018 19:33:16 +0200	[thread overview]
Message-ID: <20181030173316.GD31019@reaktio.net> (raw)
In-Reply-To: <1540846506816.50601@amazon.com>

On Mon, Oct 29, 2018 at 08:55:09PM +0000, Paraschiv, Andra-Irina wrote:
> 
> 
> On Mon, Oct 29, 2018 at 04:58:22PM +0200, Pasi Kärkkäinen wrote:
> > Hi,
> >
> > On Wed, Oct 24, 2018 at 04:20:35PM +0100, Ian Jackson wrote:
> > > Andra Paraschiv writes ("[PATCH RESEND qemu-xen-traditional] xen/pt: allow QEMU to request MSI unmasking at bind time"):
> > > > When a MSI interrupt is bound to a guest using
> > > > xc_domain_update_msi_irq (XEN_DOMCTL_bind_pt_irq) the interrupt is
> > > > left masked by default.
> > >
> > > Applied, and pushed the corresponding update to QEMU_TAG in
> > > qemu-xen-unstable.
> > >
> > > Does this patch need to be backported to earlier Xen releases ?  It
> > > wasn't clear to me whether there is new Xen code in this area without
> > > which the problem (which the patch solves) does not arise; or whether,
> > > conversely, simply running a new guest is sufficient.
> > >
> > 
> > Good question. In the earlier thread about this patch it was mentioned
> > the bug happens with latest stable version of Xen, which sounds like
> > this patch should be backported to stable Xen versions. Is that correct?
> 
> Replied later than expected, but I'm back now.
> 
> Ian, Pasi,
> 
> Right. We have this mail thread where the issue was originally reported:
> https://lists.xenproject.org/archives/html/xen-devel/2017-07/msg00915.html
> 
> And the follow-up with the patches for Xen and QEMU (not traditional):
> https://lists.xenproject.org/archives/html/xen-devel/2018-05/msg01238.html
> 
> "Hm, I think I might have fixed this issue, see:
> 
> https://git.qemu.org/?p=qemu.git;a=commit;h=a8036336609d2e184fc3543a4c439c0ba7d7f3a2
> 
> And the Xen side:
> 
> http://xenbits.xen.org/gitweb/?p=xen.git;a=commit;h=69d99d1b223fc5082400374698ddd7486e5ea953"
> 
> The Xen patch above is present in the tree from 4.10.0-rc1 tag forward.
> 

Thanks! So it looks like the patch should be applied/backported to qemu-traditional trees for Xen 4.10 and 4.11.

-- Pasi

> Thanks for feedback. Anything I can help further, we can discuss about it.
> 
> Andra
> 
> > Thanks,
> > 
> > -- Pasi
> >
> > > Regards,
> > > Ian.
> > >

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