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From: Greg KH <greg@kroah.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: stable@vger.kernel.org, x86@kernel.org,
	linux-kernel@vger.kernel.org, bernhard.kaindl@thalesgroup.com,
	Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH] x86/mm/pat: Fix L1TF stable backport for CPA
Date: Sat, 25 Aug 2018 17:07:45 +0200	[thread overview]
Message-ID: <20180825150745.GB10230@kroah.com> (raw)
In-Reply-To: <20180825135015.33547-1-andi@firstfloor.org>

On Sat, Aug 25, 2018 at 06:50:15AM -0700, Andi Kleen wrote:
> From: Andi Kleen <ak@linux.intel.com>
> 
> Patch for stable only to fix boot resets caused by the L1TF patches.
> 
> Stable trees reverted the following patch
> 
> Revert "x86/mm/pat: Ensure cpa->pfn only contains page frame numbers"
> 
>     This reverts commit 87e2bd898d3a79a8c609f183180adac47879a2a4 which is
>     commit edc3b9129cecd0f0857112136f5b8b1bc1d45918 upstream.
> 
> but the L1TF patch backported here
> 
>    x86/mm/pat: Make set_memory_np() L1TF safe
> 
>     commit 958f79b9ee55dfaf00c8106ed1c22a2919e0028b upstream
> 
>     set_memory_np() is used to mark kernel mappings not present, but it has
>     it's own open coded mechanism which does not have the L1TF protection of
>     inverting the address bits.
> 
> assumed that cpa->pfn contains a PFN. With the above patch reverted
> it does not, which causes the PMD to be set to an incorrect address
> shifted by 12 bits, which can cause early boot reset on some
> systems, like an Apollo Lake embedded system.
> 
> Convert the address to a PFN before passing it to pmd_pfn()
> 
> Thanks to Bernhard for bisecting and testing.
> 
> Cc: stable@vger.kernel.org # 4.4 and 4.9
> Reported-by: Bernhard Kaindl <bernhard.kaindl@thalesgroup.com>
> Tested-by: Bernhard Kaindl <bernhard.kaindl@thalesgroup.com>
> Signed-off-by: Andi Kleen <ak@linux.intel.com>
> ---
>  arch/x86/mm/pageattr.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Thanks for this, now queued up.

greg k-h

  reply	other threads:[~2018-08-25 15:08 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-25 13:50 [PATCH] x86/mm/pat: Fix L1TF stable backport for CPA Andi Kleen
2018-08-25 15:07 ` Greg KH [this message]
2018-08-26  4:46 ` Guenter Roeck
2018-08-26  5:06   ` Andi Kleen
2018-08-26  5:55     ` Greg KH
2018-09-06  6:48 ` Jiri Slaby
2018-09-06 20:27   ` Andi Kleen
2018-09-17 11:51     ` Greg KH
2018-09-17 12:16       ` Jiri Slaby
2018-09-17 12:20         ` Greg KH

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