linux-kernel - Re: [PATCH] x86/retpoline: Fill return stack buffer on vmexit

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Date:   Thu, 11 Jan 2018 09:49:36 +0100
From:   Boris Petkov <bp@...en8.de>
To:     Peter Zijlstra <peterz@...radead.org>,
        "Woodhouse, David" <dwmw@...zon.co.uk>
CC:     "ak@...ux.intel.com" <ak@...ux.intel.com>,
        "tim.c.chen@...ux.intel.com" <tim.c.chen@...ux.intel.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "torvalds@...ux-foundation.org" <torvalds@...ux-foundation.org>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "x86@...nel.org" <x86@...nel.org>,
        "riel@...hat.com" <riel@...hat.com>,
        "keescook@...gle.com" <keescook@...gle.com>,
        "gnomes@...rguk.ukuu.org.uk" <gnomes@...rguk.ukuu.org.uk>,
        "pjt@...gle.com" <pjt@...gle.com>,
        "Ghitulete, Razvan-alin" <rga@...zon.com>,
        "dave.hansen@...el.com" <dave.hansen@...el.com>,
        "luto@...capital.net" <luto@...capital.net>,
        "jikos@...nel.org" <jikos@...nel.org>,
        "gregkh@...ux-foundation.org" <gregkh@...ux-foundation.org>
Subject: Re: [PATCH] x86/retpoline: Fill return stack buffer on vmexit

On January 11, 2018 9:42:38 AM GMT+01:00, Peter Zijlstra <peterz@...radead.org> wrote:
>Or we teach the alternative thing to patch in a jmp to end instead of
>NOP padding the entire thing as soon as the jmp (3 bytes) fits ?

Or, even better: use alternative_call() to call functions instead of patching gazillion bytes.

-- 
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