Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933973AbeAKM0X (ORCPT + 1 other); Thu, 11 Jan 2018 07:26:23 -0500 Received: from bombadil.infradead.org ([65.50.211.133]:34423 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933376AbeAKM0V (ORCPT ); Thu, 11 Jan 2018 07:26:21 -0500 Date: Thu, 11 Jan 2018 13:26:07 +0100 From: Peter Zijlstra To: David Woodhouse Cc: Andi Kleen , Paul Turner , LKML , Linus Torvalds , Greg Kroah-Hartman , Tim Chen , Dave Hansen , tglx@linutronix.de, Kees Cook , Rik van Riel , Andy Lutomirski , Jiri Kosina , gnomes@lxorguk.ukuu.org.uk, x86@kernel.org, bp@alien8.de, rga@amazon.de, thomas.lendacky@amd.com, Josh Poimboeuf Subject: Re: [PATCH v2.1] x86/retpoline: Fill return stack buffer on vmexit Message-ID: <20180111122607.GZ6176@hirez.programming.kicks-ass.net> References: <1515670638-8552-1-git-send-email-dwmw@amazon.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1515670638-8552-1-git-send-email-dwmw@amazon.co.uk> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On Thu, Jan 11, 2018 at 11:37:18AM +0000, David Woodhouse wrote: > In accordance with the Intel and AMD documentation, we need to overwrite > all entries in the RSB on exiting a guest, to prevent malicious branch > target predictions from affecting the host kernel. This is needed both > for retpoline and for IBRS. > > Signed-off-by: David Woodhouse Tested this on my AMD Interlagos, seems to work. Tested-by: Peter Zijlstra (Intel)