From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:46805 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750829AbbF2UWo (ORCPT ); Mon, 29 Jun 2015 16:22:44 -0400 From: Bandan Das To: Greg KH Cc: stable@vger.kernel.org, Paolo Bonzini Subject: Re: KVM: nSVM: Check for NRIPS support before updating control field References: <20150629192810.GA19965@kroah.com> Date: Mon, 29 Jun 2015 16:22:42 -0400 In-Reply-To: <20150629192810.GA19965@kroah.com> (Greg KH's message of "Mon, 29 Jun 2015 12:28:10 -0700") Message-ID: MIME-Version: 1.0 Content-Type: text/plain Sender: stable-owner@vger.kernel.org List-ID: Greg KH writes: > 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? Sorry, I missed that part. I believe this bug is present since commit cfec82cb7d3 which makes it applicable to #3.0+ Bandan > thanks, > > greg k-h