linux-kernel - Re: [PATCH 1/3] pvclock: Add CPU barries to get correct version value

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Date:	Fri, 27 May 2016 08:39:50 -0700
From:	Andy Lutomirski <luto@...capital.net>
To:	Minfei Huang <mnghuan@...il.com>
Cc:	Borislav Petkov <bp@...e.de>, Paolo Bonzini <pbonzini@...hat.com>,
	Andrew Lutomirski <luto@...nel.org>,
	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>, X86 ML <x86@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/3] pvclock: Add CPU barries to get correct version value

On Thu, May 26, 2016 at 11:17 PM, Minfei Huang <mnghuan@...il.com> wrote:
> Protocol for the "version" fields is: hypervisor raises it (making it
> uneven) before it starts updating the fields and raises it again (making
> it even) when it is done.  Thus the guest can make sure the time values
> it got are consistent by checking the version before and after reading
> them.
>
> Add CPU barries after getting version value just like what function
> vread_pvclock does, because all of callees in this function is inline.

LGTM.