linux-kernel - Re: [Xen-devel] [PATCH] xen: disable PV spinlocks on HVM

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Message-ID: <20110906170255.GA29839@dumpdata.com>
Date:	Tue, 6 Sep 2011 13:02:55 -0400
From:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To:	stefano.stabellini@...citrix.com, stefan.bader@...onical.com
Cc:	xen-devel@...ts.xensource.com, linux-kernel@...r.kernel.org
Subject: Re: [Xen-devel] [PATCH] xen: disable PV spinlocks on HVM

On Tue, Sep 06, 2011 at 05:41:47PM +0100, stefano.stabellini@...citrix.com wrote:
> From: Stefano Stabellini <stefano.stabellini@...citrix.com>
> 
> PV spinlocks cannot possibly work with the current code because they are
> enabled after pvops patching has already been done, and because PV
> spinlocks use a different data structure than native spinlocks so we
> cannot switch between them dynamically. A spinlock that has been taken
> once by the native code (__ticket_spin_lock) cannot be taken by
> __xen_spin_lock even after it has been released.

Let me stick it on my 3.1-rc5 bug-fix list and add stable@...nel.org to it.

Stefan, if you have some time this week, and can test it - I can also
stick 'Tested-by' if you would like.

Thinking to send the patches on Friday.

> 
> Reported-by: Stefan Bader <stefan.bader@...onical.com>
> Signed-off-by: Stefano Stabellini <stefano.stabellini@...citrix.com>
> ---
>  arch/x86/xen/smp.c |    1 -
>  1 files changed, 0 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
> index e79dbb9..51339b4 100644
> --- a/arch/x86/xen/smp.c
> +++ b/arch/x86/xen/smp.c
> @@ -522,7 +522,6 @@ static void __init xen_hvm_smp_prepare_cpus(unsigned int max_cpus)
>  	WARN_ON(xen_smp_intr_init(0));
>  
>  	xen_init_lock_cpu(0);
> -	xen_init_spinlocks();
>  }
>  
>  static int __cpuinit xen_hvm_cpu_up(unsigned int cpu)
> -- 
> 1.7.2.3
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@...ts.xensource.com
> http://lists.xensource.com/xen-devel
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