linux-kernel - Re: [PATCH] x86/xen: Initialize cr4 shadow for 64-bit PV(H) guests

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Message-ID: <CALCETrUip-ct=uksKu4i4znqLZ+mvTYMi_fmZK5sjf_2A2pHBw@mail.gmail.com>
Date:	Mon, 23 Feb 2015 08:09:12 -0800
From:	Andy Lutomirski <luto@...capital.net>
To:	Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	David Vrabel <david.vrabel@...rix.com>,
	"xen-devel@...ts.xenproject.org" <xen-devel@...ts.xenproject.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86/xen: Initialize cr4 shadow for 64-bit PV(H) guests

On Mon, Feb 23, 2015 at 8:01 AM, Boris Ostrovsky
<boris.ostrovsky@...cle.com> wrote:
> Commit 1e02ce4cccdc ("x86: Store a per-cpu shadow copy of CR4")
> introduced CR4 shadows.
>
> These shadows are initialized in early boot code. The commit missed
> initialization for 64-bit PV(H) guests that this patch adds.

Whoops, worry.

This is needed for 3.21, right?

--Andy

>
> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@...cle.com>
> ---
>  arch/x86/xen/enlighten.c |    1 +
>  1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
> index bd8b845..7393f3e 100644
> --- a/arch/x86/xen/enlighten.c
> +++ b/arch/x86/xen/enlighten.c
> @@ -1741,6 +1741,7 @@ asmlinkage __visible void __init xen_start_kernel(void)
>  #ifdef CONFIG_X86_32
>         i386_start_kernel();
>  #else
> +       cr4_init_shadow(); /* 32b kernel does this in i386_start_kernel() */
>         x86_64_start_reservations((char *)__pa_symbol(&boot_params));
>  #endif
>  }
> --
> 1.7.1
>



-- 
Andy Lutomirski
AMA Capital Management, LLC
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