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From: "H. Peter Anvin" <hpa@zytor.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>,
	olaf@aepfle.de, bp@alien8.de, apw@canonical.com, x86@kernel.org,
	tglx@linutronix.de, devel@linuxdriverproject.org,
	gregkh@linuxfoundation.org, jasowang@redhat.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] X86: Add a check to catch Xen emulation of Hyper-V
Date: Thu, 31 Jan 2013 13:41:10 -0800	[thread overview]
Message-ID: <510AE4F6.1050407@zytor.com> (raw)
In-Reply-To: <5108ED9702000078000BAA08@nat28.tlf.novell.com>

On 01/30/2013 12:53 AM, Jan Beulich wrote:
> 
> I'm not convinced that's the right approach - any hypervisor
> could do similar emulation, and hence you either want to make
> sure you run on Hyper-V (by excluding all others), or you
> tolerate using the emulation (which may require syncing up with
> the other guest implementations so that shared resources don't
> get used by two parties).
> 
> I also wonder whether using the Hyper-V emulation (where
> useful, there might not be anything right now, but this may
> change going forward) when no Xen support is configured
> wouldn't be better than not using anything...
> 

I'm confused about "the right approach" here is.  As far as I
understand, this only can affect a Xen guest where HyperV guest support
is enabled but not Xen support, and only because Xen emulates HyperV but
does so incorrectly.

This is a Xen bug, and as such it makes sense to reject Xen
specifically.  If another hypervisor emulates HyperV and does so
correctly there seems to be no reason to reject it.

	-hpa



  parent reply	other threads:[~2013-01-31 21:42 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-30  0:51 [PATCH 0/3] X86: Deliver Hyper-V interrupts on a seperate IDT vector K. Y. Srinivasan
2013-01-30  0:51 ` [PATCH 1/3] x86: Hyper-V: register clocksource only if its advertised K. Y. Srinivasan
2013-01-30  0:51   ` [PATCH 2/3] X86: Add a check to catch Xen emulation of Hyper-V K. Y. Srinivasan
2013-01-30  8:53     ` Jan Beulich
2013-01-30 18:12       ` KY Srinivasan
2013-01-30 18:19         ` H. Peter Anvin
2013-01-31  7:37         ` Jan Beulich
2013-01-31 14:46           ` KY Srinivasan
2013-01-31 15:53             ` KY Srinivasan
2013-01-31 16:45               ` Jan Beulich
2013-01-31 18:29                 ` H. Peter Anvin
2013-01-31 21:41       ` H. Peter Anvin [this message]
2013-02-01 13:19         ` Stefano Stabellini
2013-02-01 15:10           ` KY Srinivasan
2013-02-01 19:34             ` KY Srinivasan
2013-01-30  0:51   ` [PATCH 3/3] X86: Handle Hyper-V vmbus interrupts as special hypervisor interrupts K. Y. Srinivasan
2013-01-30  8:58     ` Jan Beulich
2013-01-31 14:55       ` KY Srinivasan
2013-02-04  1:21 [PATCH 0/3] X86: Deliver Hyper-V interrupts on a seperate IDT vector K. Y. Srinivasan
2013-02-04  1:22 ` [PATCH 1/3] x86: Hyper-V: register clocksource only if its advertised K. Y. Srinivasan
2013-02-04  1:22   ` [PATCH 2/3] X86: Add a check to catch Xen emulation of Hyper-V K. Y. Srinivasan
2013-04-17  7:06     ` Michael S. Tsirkin
2013-04-17 13:20       ` KY Srinivasan
2013-04-17 12:48         ` Michael S. Tsirkin
2013-04-17 14:12           ` KY Srinivasan
2013-04-17 13:25             ` Michael S. Tsirkin
2013-04-17 14:34               ` KY Srinivasan
2013-04-17 13:48                 ` Michael S. Tsirkin
2013-04-17 15:31                   ` KY Srinivasan
2013-04-17 15:50                     ` Jan Beulich
2013-04-17 16:28                       ` KY Srinivasan
2013-04-18  7:48                         ` Michael S. Tsirkin
2013-04-18 13:23                           ` KY Srinivasan
2013-04-18 13:30                             ` KY Srinivasan
2013-04-17 13:52         ` Jan Beulich
2013-04-17 13:01           ` Michael S. Tsirkin
2013-04-17 13:11             ` Michael S. Tsirkin
2013-04-17 14:09             ` Jan Beulich
2013-04-17 15:17               ` H. Peter Anvin

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