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

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Date:	Mon, 23 Feb 2015 11:16:24 -0500
From:	Boris Ostrovsky <boris.ostrovsky@...cle.com>
To:	Andy Lutomirski <luto@...capital.net>
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 02/23/2015 11:09 AM, Andy Lutomirski wrote:
> 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?

It would have been 3.20, I think. Which is now 4.0.


-boris

>
> --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
>>
>
>

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