linux-kernel - [PATCH] xen/x86: drop redundant zeroing from cpu_initialize

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Date:   Thu, 16 Sep 2021 17:05:29 +0200
From:   Jan Beulich <jbeulich@...e.com>
To:     Juergen Gross <jgross@...e.com>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc:     Stefano Stabellini <sstabellini@...nel.org>,
        lkml <linux-kernel@...r.kernel.org>,
        "xen-devel@...ts.xenproject.org" <xen-devel@...ts.xenproject.org>
Subject: [PATCH] xen/x86: drop redundant zeroing from cpu_initialize_context()

Just after having obtained the pointer from kzalloc() there's no reason
at all to set part of the area to all zero yet another time. Similarly
there's no point explicitly clearing "ldt_ents".

Signed-off-by: Jan Beulich <jbeulich@...e.com>

--- a/arch/x86/xen/smp_pv.c
+++ b/arch/x86/xen/smp_pv.c
@@ -290,8 +290,6 @@ cpu_initialize_context(unsigned int cpu,
 
 	gdt = get_cpu_gdt_rw(cpu);
 
-	memset(&ctxt->fpu_ctxt, 0, sizeof(ctxt->fpu_ctxt));
-
 	/*
 	 * Bring up the CPU in cpu_bringup_and_idle() with the stack
 	 * pointing just below where pt_regs would be if it were a normal
@@ -308,8 +306,6 @@ cpu_initialize_context(unsigned int cpu,
 
 	xen_copy_trap_info(ctxt->trap_ctxt);
 
-	ctxt->ldt_ents = 0;
-
 	BUG_ON((unsigned long)gdt & ~PAGE_MASK);
 
 	gdt_mfn = arbitrary_virt_to_mfn(gdt);