From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH] KVM: nVMX: Fix IRQs inject to L2 which belong to L1 since race Date: Fri, 04 Jul 2014 13:28:34 +0200 Message-ID: <53B68FE2.9070700@redhat.com> References: <1404284054-51863-1-git-send-email-wanpeng.li@linux.intel.com> <53B3CA6A.4050902@siemens.com> <20140703065955.GA4236@kernel> <20140704025250.GA2849@kernel> <53B63EF2.6000800@siemens.com> <53B674CD.2090906@siemens.com> <53B67602.4040604@redhat.com> <53B68781.9080200@siemens.com> <53B68B07.8020509@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Gleb Natapov , Hu Robert , kvm@vger.kernel.org, linux-kernel@vger.kernel.org To: Jan Kiszka , Wanpeng Li , Bandan Das Return-path: In-Reply-To: <53B68B07.8020509@siemens.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org Il 04/07/2014 13:07, Jan Kiszka ha scritto: > On 2014-07-04 12:52, Jan Kiszka wrote: >> On 2014-07-04 11:38, Paolo Bonzini wrote: >>> Il 04/07/2014 11:33, Jan Kiszka ha scritto: >>>> >>>> The compiler is not aware of the fact that push/pop exists in this >>>> function and, thus, places the vmcs parameter on the stack without >>>> reserving the space. So the pushfq will overwrite the vmcs pointer and >>>> let the function fail. >>> >>> Is that just a missing "memory" clobber? push/pop clobbers memory. >> >> Nope, we would needs some clobber like "stack". I wonder what is >> required to use push in inline assembly safely? > > My colleague just found the answer: -mno-red-zone is required for 64-bit > in order to play freely with the stack (or you need to stay off that > zone, apparently some 128 bytes below the stack pointer). The kernel > sets that switch, our unit tests do not. Are you posting a patch? (Also, what compiler is that?) Paolo