linux-kernel - Re: [Xen-devel] [V0 PATCH] pvh: Disable PSE feature for now

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Message-Id: <52E796EB0200007800117804@nat28.tlf.novell.com>
Date:	Tue, 28 Jan 2014 10:39:23 +0000
From:	"Jan Beulich" <JBeulich@...e.com>
To:	"Mukesh Rathor" <mukesh.rathor@...cle.com>
Cc:	<roger.pau@...rix.com>,
	"xen-devel" <xen-devel@...ts.xenproject.org>,
	<konrad.wilk@...cle.com>, <linux-kernel@...r.kernel.org>
Subject: Re: [Xen-devel] [V0 PATCH] pvh: Disable PSE feature for now

>>> On 28.01.14 at 03:18, Mukesh Rathor <mukesh.rathor@...cle.com> wrote:
> Until now, xen did not expose PSE to pvh guest, but a patch was submitted
> to xen list to enable bunch of features for a pvh guest. PSE has not been
> looked into for PVH, so until we can do that and test it to make sure it
> works, disable the feature to avoid flood of bugs.
> 
> Signed-off-by: Mukesh Rathor <mukesh.rathor@...cle.com>
> ---
>  arch/x86/xen/enlighten.c |    5 +++++
>  1 files changed, 5 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
> index a4d7b64..4e952046 100644
> --- a/arch/x86/xen/enlighten.c
> +++ b/arch/x86/xen/enlighten.c
> @@ -1497,6 +1497,11 @@ static void __init xen_pvh_early_guest_init(void)
>  	xen_have_vector_callback = 1;
>  	xen_pvh_set_cr_flags(0);
>  
> +        /* pvh guests are not quite ready for large pages yet */
> +        setup_clear_cpu_cap(X86_FEATURE_PSE);
> +        setup_clear_cpu_cap(X86_FEATURE_PSE36);

And why would you not want to also turn of 1Gb pages then?

Jan

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