From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/3] xen/arm: introduce xen_read_wallclock
Date: Mon, 09 Nov 2015 17:16:05 +0100 [thread overview]
Message-ID: <17175481.GKnbuH0F1P@wuerfel> (raw)
In-Reply-To: <alpine.DEB.2.02.1511091348440.23825@kaball.uk.xensource.com>
On Monday 09 November 2015 13:53:30 Stefano Stabellini wrote:
> On Fri, 6 Nov 2015, Arnd Bergmann wrote:
> > I'm not quite sure about how the split between pvclock_wall_clock and
> > the delta works. Normally I'd expect that pvclock_wall_clock is the wallclock
> > time as it was at boot, while delta is the number of expired nanoseconds
> > since boot. However it is unclear why the latter has a longer range
> > (539 years starting at boot, rather than 126 years starting in 1970).
>
> Actually we already have a sec overflow field in struct shared_info on
> the hypervisor side, called wc_sec_hi. I just need to make use of it in
> Linux. See:
>
> http://xenbits.xen.org/gitweb/?p=xen.git;a=blob_plain;f=xen/include/public/xen.h;hb=HEAD
>
> Thanks for raising my attention to the problem,
Sounds good for Xen on ARM. This same interface is also used on
KVM, right? Does the extension also work there?
Arnd
next prev parent reply other threads:[~2015-11-09 16:16 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-05 17:09 [PATCH 0/3] Xen wallclock on arm and arm64 Stefano Stabellini
2015-11-05 17:09 ` [PATCH 1/3] xen/arm: introduce xen_read_wallclock Stefano Stabellini
2015-11-05 18:53 ` Arnd Bergmann
2015-11-06 15:09 ` Stefano Stabellini
2015-11-06 15:56 ` Arnd Bergmann
2015-11-09 13:53 ` Stefano Stabellini
2015-11-09 16:16 ` Arnd Bergmann [this message]
2015-11-09 17:14 ` Stefano Stabellini
2015-11-09 20:42 ` Arnd Bergmann
2015-11-06 12:26 ` Mark Rutland
2015-11-06 14:34 ` Stefano Stabellini
2015-11-05 17:09 ` [PATCH 2/3] xen/arm: introduce HYPERVISOR_dom0_op on arm and arm64 Stefano Stabellini
2015-11-05 17:21 ` [Xen-devel] " Jan Beulich
2015-11-06 14:45 ` Stefano Stabellini
2015-11-05 17:09 ` [PATCH 3/3] xen/arm: set the system time in Xen via the XENPF_settime hypercall Stefano Stabellini
2015-11-05 17:45 ` [Xen-devel] " David Vrabel
2015-11-06 14:59 ` Stefano Stabellini
2015-11-05 18:58 ` Arnd Bergmann
2015-11-09 14:10 ` Stefano Stabellini
2015-11-09 16:10 ` Arnd Bergmann
2015-11-09 17:17 ` Stefano Stabellini
2015-11-09 17:42 ` Stefano Stabellini
2015-11-09 20:45 ` Arnd Bergmann
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