linux-kernel - [tip:x86/microcode] x86/microcode: Remove unnecessary paravirt

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Message-ID: <tip-84aba677f009e20185aea322563389ad56e0ef7e@git.kernel.org>
Date:	Wed, 17 Feb 2016 04:12:16 -0800
From:	tip-bot for Boris Ostrovsky <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	bp@...e.de, mingo@...nel.org, boris.ostrovsky@...cle.com,
	linux-kernel@...r.kernel.org, peterz@...radead.org,
	torvalds@...ux-foundation.org, hpa@...or.com, tglx@...utronix.de
Subject: [tip:x86/microcode] x86/microcode:
  Remove unnecessary paravirt_enabled check

Commit-ID:  84aba677f009e20185aea322563389ad56e0ef7e
Gitweb:     http://git.kernel.org/tip/84aba677f009e20185aea322563389ad56e0ef7e
Author:     Boris Ostrovsky <boris.ostrovsky@...cle.com>
AuthorDate: Tue, 16 Feb 2016 09:43:19 +0100
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Wed, 17 Feb 2016 08:46:07 +0100

x86/microcode: Remove unnecessary paravirt_enabled check

Commit:

  a18a0f6850d4 ("x86, microcode: Don't initialize microcode code on paravirt")

added a paravirt test in microcode_init(), primarily to avoid making
mc_bp_resume()->load_ucode_ap()->check_loader_disabled_ap() calls
because on 32-bit kernels this callchain ends up using __pa_nodebug()
macro which is invalid for Xen PV guests.

A subsequent commit:

  fbae4ba8c4a3 ("x86, microcode: Reload microcode on resume")

eliminated this callchain thus making a18a0f6850d4 unnecessary.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@...cle.com>
Signed-off-by: Borislav Petkov <bp@...e.de>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: david.vrabel@...rix.com
Cc: konrad.wilk@...cle.com
Cc: xen-devel@...ts.xenproject.org
Link: http://lkml.kernel.org/r/1455612202-14414-2-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/kernel/cpu/microcode/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index cea8552..ac360bf 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -623,7 +623,7 @@ int __init microcode_init(void)
 	struct cpuinfo_x86 *c = &boot_cpu_data;
 	int error;
 
-	if (paravirt_enabled() || dis_ucode_ldr)
+	if (dis_ucode_ldr)
 		return -EINVAL;
 
 	if (c->x86_vendor == X86_VENDOR_INTEL)