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Date:   Wed, 12 May 2021 10:37:37 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Lai Jiangshan <laijs@linux.alibaba.com>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        LKML <linux-kernel@vger.kernel.org>, x86@kernel.org,
        Joerg Roedel <joro@8bytes.org>, Borislav Petkov <bp@suse.de>
Subject: Re: [patch 1/2 v2] x86/cpu: Init AP exception handling from
 cpu_init_secondary()
Message-ID: <YJuT0XfLAlkM6BZM@hirez.programming.kicks-ass.net>
References: <20210507110210.147106915@linutronix.de>
 <20210507114000.429303187@linutronix.de>
 <ccbd2f11-bb74-19bd-cf5c-d524625f9a0d@linux.alibaba.com>
 <87wns8ko48.ffs@nanos.tec.linutronix.de>
 <87k0o6gtvu.ffs@nanos.tec.linutronix.de>
 <d5a7434c-9205-b6c6-c7ad-423e7050bc62@linux.alibaba.com>
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On Tue, May 11, 2021 at 05:25:35PM +0800, Lai Jiangshan wrote:
> 
> 
> On 2021/5/11 05:29, Thomas Gleixner wrote:
> > From: Borislav Petkov <bp@suse.de>
> > 
> > SEV-ES guests require properly setup task register with which the TSS
> > descriptor in the GDT can be located so that the IST-type #VC exception
> > handler which they need to function properly, can be executed.
> > 
> > This setup needs to happen before attempting to load microcode in
> > ucode_cpu_init() on secondary CPUs which can cause such #VC exceptions.
> > 
> > Simplify the machinery by running that exception setup from a new function
> > cpu_init_secondary() and explicitly call cpu_init_exception_handling() for
> > the boot CPU before cpu_init(). The latter prepares for fixing and
> > simplifying the exception/IST setup on the boot CPU.
> > 
> > There should be no functional changes resulting from this patch.
> > 
> > [ tglx: Reworked it so cpu_init_exception_handling() stays seperate ]
> > 
> > Signed-off-by: Borislav Petkov <bp@suse.de>
> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> 
> 
> For both patches:
> 
> Reviewed-by: Lai Jiangshan <laijs@linux.alibaba.com>

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>