From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: Stefano Stabellini <sstabellini@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>,
Chris Patterson <cjp256@gmail.com>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
xen-devel@lists.xenproject.org,
Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Subject: Re: [PATCH] kernel-parameters: document earlycon=xenboot
Date: Fri, 8 Apr 2016 10:41:58 -0400 [thread overview]
Message-ID: <20160408144158.GB15411@char.us.oracle.com> (raw)
In-Reply-To: <alpine.DEB.2.10.1604051812350.31453@sstabellini-ThinkPad-X230>
On Tue, Apr 05, 2016 at 06:16:35PM -0700, Stefano Stabellini wrote:
> On Tue, 5 Apr 2016, Konrad Rzeszutek Wilk wrote:
> > On Tue, Apr 05, 2016 at 11:43:36AM -0400, Chris Patterson wrote:
> > > On Tue, Apr 5, 2016 at 9:49 AM, Konrad Rzeszutek Wilk
> > > <konrad.wilk@oracle.com> wrote:
> > > > On Mon, Apr 04, 2016 at 10:48:11PM -0400, Chris Patterson wrote:
> > > >> Add earlycon=xenboot option to Documentation/kernel-parameters.txt.
> > > >>
> > > >
> > > > But it is not true.
> > > >
> > > > I tried this on x86: "earlycon=xenboot console=tty0"
>
> Was it a PV guest? Do you have SERIAL_EARLYCON enabled in your kconfig?
Yes, dom0 in fact.
> Does Xen allow DomU debug output via HYPERVISOR_console_io in your config?
Yes. That works.
>
>
> > > I can investigate further, but hopefully Stefano can chime in more
> > > definitively on what is supported.
> > >
> > > I used "earlycon=xenboot console=hvc0" with success for dom0 on my
> > > ARM64 platform.
> >
> > Perhaps the documentation should also have [ARM], like some of the
> > other ones?
> >
>
> I don't recall whether I actually tested earlycon on x86, but looking at
> the code it should work, at least for PV guests (you need to be able to
> issue hypercalls and HVM guests cannot do that until they map the
> hypercall page).
>
> In any case given that x86 has earlyprintk, specifying
> xenboot as only available for ARM and ARM64 is also OK for me, but I
> would prefer to keep it arch-independent given that earlycon is.
/me nods.
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next prev parent reply other threads:[~2016-04-08 14:42 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1459824491-15716-1-git-send-email-cjp256@gmail.com>
2016-04-05 13:49 ` [PATCH] kernel-parameters: document earlycon=xenboot Konrad Rzeszutek Wilk
2016-04-05 15:43 ` Chris Patterson
[not found] ` <CABZSBQdyVhaDS+Ry0hWbj0ZDn1tH_Wm-NoCs-oPGy0TTzgXtXA@mail.gmail.com>
2016-04-05 16:42 ` Konrad Rzeszutek Wilk
2016-04-05 21:22 ` Chris Patterson
2016-04-06 1:16 ` Stefano Stabellini
[not found] ` <alpine.DEB.2.10.1604051812350.31453@sstabellini-ThinkPad-X230>
2016-04-08 14:41 ` Konrad Rzeszutek Wilk [this message]
2016-04-05 2:48 Chris Patterson
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