[PATCH 1/4] x86/microcode: Remove unnecessary paravirt_enabled check

From: Borislav Petkov
Date: Tue Feb 16 2016 - 03:43:35 EST


From: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>

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@xxxxxxxxxx>
Cc: david.vrabel@xxxxxxxxxx
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: konrad.wilk@xxxxxxxxxx
Cc: mingo@xxxxxxxxxx
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: x86-ml <x86@xxxxxxxxxx>
Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1455203598-14378-1-git-send-email-boris.ostrovsky@xxxxxxxxxx
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
---
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 faec7120c508..86ec92a0bbbe 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -630,7 +630,7 @@ 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)
--
2.3.5