From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:49243 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752080AbbF2T2L (ORCPT ); Mon, 29 Jun 2015 15:28:11 -0400 Date: Mon, 29 Jun 2015 12:28:10 -0700 From: Greg KH To: Bandan Das Cc: stable@vger.kernel.org, Paolo Bonzini Subject: Re: KVM: nSVM: Check for NRIPS support before updating control field Message-ID: <20150629192810.GA19965@kroah.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: stable-owner@vger.kernel.org List-ID: On Mon, Jun 29, 2015 at 03:18:51PM -0400, Bandan Das wrote: > > Commit f104765b4f81fd74d69e0eb161e89096deade2db upstream. > > This causes the L1 guest to crash when running a nested guest > with an AMD processor that doesn't support NRIPS. > > If hardware doesn't support DecodeAssist - a feature that provides > more information about the intercept in the VMCB, KVM decodes the > instruction and then updates the next_rip vmcb control field. > However, NRIP support itself depends on cpuid Fn8000_000A_EDX[NRIPS]. > Since skip_emulated_instruction() doesn't verify nrip support > before accepting control.next_rip as valid, avoid writing this > field if support isn't present. > > Signed-off-by: Bandan Das > Signed-off-by: Paolo Bonzini > --- > arch/x86/kvm/svm.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) What stable kernel trees do you want this applied to? thanks, greg k-h