linux-kernel - Re: [PATCH v2 3/3] paravirt: rename paravirt_enabled to paravirt

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Date:	Wed, 17 Feb 2016 21:49:55 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	"Luis R. Rodriguez" <mcgrof@...nel.org>
Cc:	Boris Ostrovsky <boris.ostrovsky@...cle.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	Andrew Cooper <andrew.cooper3@...rix.com>,
	David Vrabel <david.vrabel@...rix.com>,
	Andy Lutomirski <luto@...capital.net>,
	Juergen Gross <jgross@...e.com>,
	Michael Brown <mcb30@...e.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Andrey Ryabinin <aryabinin@...tuozzo.com>,
	Joerg Roedel <joro@...tes.org>,
	Robert Moore <robert.moore@...el.com>,
	Mauro Carvalho Chehab <mchehab@....samsung.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	Xen Devel <xen-devel@...ts.xensource.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Rusty Russell <rusty@...tcorp.com.au>,
	Jan Beulich <JBeulich@...e.com>, Lv Zheng <lv.zheng@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	long.wanglong@...wei.com, Fengguang Wu <fengguang.wu@...el.com>,
	qiuxishi@...wei.com, Andrey Ryabinin <ryabinin.a.a@...il.com>,
	david.e.box@...el.com, X86 ML <x86@...nel.org>,
	Ingo Molnar <mingo@...hat.com>
Subject: Re: [PATCH v2 3/3] paravirt: rename paravirt_enabled to
 paravirt_legacy

On Wed, Feb 17, 2016 at 12:07:13PM -0800, Luis R. Rodriguez wrote:
> OK so here's a wiki to keep track of progress of the difference uses:
> 
> http://kernelnewbies.org/KernelProjects/remove-paravirt-enabled
> 
> It seems we have a resolution one way or another for all except for
> the use on arch/x86/mm/dump_pagetables.c, is that right?

Why not?

I think we should simply check the range as ffff800000000000 -
ffff87ffffffffff is practically an ABI and nothing should be mapped
there anyway. No need for paravirt_enabled() there either.

---
diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
index 4a6f1d9b5106..de1ee3a40250 100644
--- a/arch/x86/mm/dump_pagetables.c
+++ b/arch/x86/mm/dump_pagetables.c
@@ -358,20 +358,20 @@ static void walk_pud_level(struct seq_file *m, struct pg_state *st, pgd_t addr,
 #define pgd_none(a)  pud_none(__pud(pgd_val(a)))
 #endif
 
-#ifdef CONFIG_X86_64
 static inline bool is_hypervisor_range(int idx)
 {
+#ifdef CONFIG_X86_64
+
 	/*
 	 * ffff800000000000 - ffff87ffffffffff is reserved for
 	 * the hypervisor.
 	 */
-	return paravirt_enabled() &&
-		(idx >= pgd_index(__PAGE_OFFSET) - 16) &&
+	return	(idx >= pgd_index(__PAGE_OFFSET) - 16) &&
 		(idx < pgd_index(__PAGE_OFFSET));
-}
 #else
-static inline bool is_hypervisor_range(int idx) { return false; }
+	return false;
 #endif
+}
 
 static void ptdump_walk_pgd_level_core(struct seq_file *m, pgd_t *pgd,
 				       bool checkwx)


-- 
Regards/Gruss,
    Boris.

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