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From: Olaf Hering <olaf@aepfle.de>
To: KY Srinivasan <kys@microsoft.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Greg KH <gregkh@linuxfoundation.org>,
	"Jan Beulich (JBeulich@suse.com)" <JBeulich@suse.com>
Subject: Re: [PATCH] x86: Hyper-V: register clocksource only if its advertised
Date: Fri, 25 Jan 2013 18:19:23 +0100	[thread overview]
Message-ID: <20130125171923.GA19306@aepfle.de> (raw)
In-Reply-To: <500ca90f5d3e4d4f80c7fb62c34d36f0@BLUPR03MB050.namprd03.prod.outlook.com>

On Fri, Jan 25, KY Srinivasan wrote:

> My fear is that there is no guarantee that Xen would not emulate this
> feature in the spirit of making Hyper-V emulation "more" complete.
> Since all this problem is because Xen thinks it is running a viridian
> domain (when in fact it is running Linux), I felt we should explore
> why the viridian tag got set for a Linux VM. If we can fix that we
> would have a solution that does not depend upon assuming that Xen
> would not emulate a particular Hyper-V feature.

In my opinion this logic is backwards. A host provides a set of
functionality/features to a given guest, no matter what runs inside the
guest. And the guest can query the feature list and configure itself
accordingly. In this specific case the guest finds feature A (the cpuid
result) and expects that feature B (a clock source) is present as well,
even if feature B has its very own availability flag.

Maybe I miss your point.

Olaf

  reply	other threads:[~2013-01-25 17:19 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-25 13:37 [PATCH] x86: Hyper-V: register clocksource only if its advertised Olaf Hering
2013-01-25 16:10 ` Greg KH
2013-01-25 16:43 ` KY Srinivasan
2013-01-25 16:54   ` Olaf Hering
2013-01-25 17:04     ` KY Srinivasan
2013-01-25 17:19       ` Olaf Hering [this message]
2013-01-25 17:39         ` KY Srinivasan
2013-01-25 20:00           ` Olaf Hering
2013-01-25 20:03             ` KY Srinivasan
2013-01-26 16:57             ` KY Srinivasan
2013-01-26 18:21               ` Olaf Hering
2013-01-28 17:44           ` Stefano Stabellini
2013-01-29  8:35             ` Jan Beulich
2013-01-29  9:26               ` Olaf Hering
2013-01-29 14:32                 ` KY Srinivasan
2013-01-29 15:30                   ` Stefano Stabellini
2013-01-29 15:58                     ` KY Srinivasan
2013-01-29 16:14                       ` Stefano Stabellini

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