linux-kernel - Re: [PATCH v4 1/2] XEN/X86: Improve semantic support for x86_init.mapping.pagetable

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Message-ID: <20120824134459.GA6171@x1.osrc.amd.com>
Date:	Fri, 24 Aug 2012 15:45:00 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	Attilio Rao <attilio.rao@...rix.com>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"mingo@...hat.com" <mingo@...hat.com>,
	"hpa@...or.com" <hpa@...or.com>, "x86@...nel.org" <x86@...nel.org>,
	Stefano Stabellini <Stefano.Stabellini@...citrix.com>
Subject: Re: [PATCH v4 1/2] XEN/X86: Improve semantic support for
 x86_init.mapping.pagetable_reserve

On Fri, Aug 24, 2012 at 02:24:00PM +0100, Attilio Rao wrote:
> Please stop referring to your opinion as if they are the only source
> of truth. Actually here is a matter of comparing prices. We thought
> accounting for different { start, end } was a viable option, you want
> something simpler and as a x86-maintainer you enforce your opinion
> over here. But this doesn't mean what the patch does is "wrong".

If you're adding code to x86 with no apparent reason, it is wrong, and
it is not a matter of personal opinion. And to be very specific, I mean
the hunk below.

If it doesn't fix any issue on x86 but is only for documentation, we
don't want it.

In /arch/x86/xen/ you can stick whatever crap you want and whatever
bullshit bingo you can come up with...

--
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index e0e6990..f4b750d 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -92,6 +92,10 @@ static void __init find_early_table_space(struct map_range *mr, unsigned long en
 
 void __init native_pagetable_reserve(u64 start, u64 end)
 {
+	if (start < PFN_PHYS(pgt_buf_start) || end > PFN_PHYS(pgt_buf_top))
+		panic("Invalid address range: [%#llx-%#llx] should be a subset of [%#llx-%#llx]\n",
+			start, end, (u64)PFN_PHYS(pgt_buf_start),
+			(u64)PFN_PHYS(pgt_buf_top));
 	memblock_reserve(start, end - start);
 }

-- 
Regards/Gruss,
Boris.
--
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