Re: [PATCH] xen/x86: Don't try to write syscall-related MSRs for PV guests

Path	csiph.com!news.mixmin.net!aioe.org!bofh.it!news.nic.it!robomod
From	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH] xen/x86: Don't try to write syscall-related MSRs for PV guests
Date	Mon, 21 Sep 2015 17:40:02 +0200
Message-ID	<qbbma-2la-19@gated-at.bofh.it> (permalink)
References	<qb9aH-7Hp-37@gated-at.bofh.it>
X-Original-To	Boris Ostrovsky <boris.ostrovsky@oracle.com>
MIME-Version	1.0
Content-Type	text/plain; charset=us-ascii
Content-Disposition	inline
User-Agent	Mutt/1.5.23 (2014-03-12)
X-Source-IP	aserv0022.oracle.com [141.146.126.234]
Sender	robomod@news.nic.it
List-ID	<linux-kernel.vger.kernel.org>
X-Mailing-List	linux-kernel@vger.kernel.org
Approved	robomod@news.nic.it
Lines	34
Organization	linux.* mail to news gateway
X-Original-Cc	david.vrabel@citrix.com, xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org
X-Original-Date	Mon, 21 Sep 2015 11:30:35 -0400
X-Original-Message-ID	<20150921153034.GD13722@l.oracle.com>
X-Original-References	<1442840968-23052-1-git-send-email-boris.ostrovsky@oracle.com>
X-Original-Sender	linux-kernel-owner@vger.kernel.org
Xref	csiph.com linux.kernel:1229484

Show key headers only | View raw

On Mon, Sep 21, 2015 at 09:09:28AM -0400, Boris Ostrovsky wrote:
> For PV guests these registers are set up by hypervisor and thus
> should not be written by the guest. The comment in xen_write_msr_safe()
> says so but we still write the MSRs, causing the hypervisor to
> print a warning.
> 
> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

> ---
>  arch/x86/xen/enlighten.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
> index 30d12af..1f1dbd2 100644
> --- a/arch/x86/xen/enlighten.c
> +++ b/arch/x86/xen/enlighten.c
> @@ -1077,6 +1077,7 @@ static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
>  		/* Fast syscall setup is all done in hypercalls, so
>  		   these are all ignored.  Stub them out here to stop
>  		   Xen console noise. */
> +		break;
>  
>  	default:
>  		if (!pmu_msr_write(msr, low, high, &ret))
> -- 
> 2.1.0
> 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next — Previous in thread | Find similar | Unroll thread

Thread

[PATCH] xen/x86: Don't try to write syscall-related MSRs for PV guests Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2015-09-21 15:20 +0200
  Re: [PATCH] xen/x86: Don't try to write syscall-related MSRs for PV  guests Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> - 2015-09-21 17:40 +0200

csiph-web