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Date:   Thu, 7 Feb 2019 10:40:21 -0800
From:   "Luck, Tony" <tony.luck@intel.com>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Linus Torvalds <torvalds@linux-foundation.org>,
        Dan Williams <dan.j.williams@intel.com>,
        Ingo Molnar <mingo@kernel.org>,
        Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Andy Lutomirski <luto@kernel.org>,
        Borislav Petkov <bp@alien8.de>,
        Thomas Gleixner <tglx@linutronix.de>,
        Rik van Riel <riel@surriel.com>
Subject: Re: [GIT PULL] x86/mm changes for v4.21
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On Thu, Feb 07, 2019 at 06:57:20PM +0100, Peter Zijlstra wrote:
> Something like so then? AFAICT CLFLUSH will also #GP if feed it crap.

Correct. CFLUSH will also #GP on a non-canonical address.

> -		__flush_tlb_one_kernel(__cpa_addr(cpa, i));
> +		__flush_tlb_one_kernel(fix_addr(__cpa_addr(cpa, i)));


> -			clflush_cache_range_opt((void *)addr, PAGE_SIZE);
> +			clflush_cache_range_opt((void *)fix_addr(addr), PAGE_SIZE);

Looks like as close as you can get without being crazy. Many/most
of the apparent function calls here are going to be inlined. So
likely safe.

Tried it out and it works!

So:

Tested-by: Tony Luck <tony.luck@intel.com>

Thanks

-Tony