From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yang Weijiang Subject: Re: [Qemu-devel][PATCH 2/4] Add CET SHSTK and IBT CPUID feature-word definitions. Date: Sat, 29 Dec 2018 23:26:43 +0800 Message-ID: <20181229152642.GA6590@localhost.localdomain> References: <30d79c2d6fa0658cd2818c21da852fd4dfeeae1c.1545806972.git.weijiang.yang@intel.com> <97d6366b-df95-cf00-d652-3176547ae5ca@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: qemu-devel@nongnu.org, rkrcmar@redhat.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, mst@redhat.com, yu-cheng.yu@intel.com, yi.z.zhang@intel.com, hjl.tools@gmail.com, Zhang Yi To: Paolo Bonzini Return-path: Content-Disposition: inline In-Reply-To: <97d6366b-df95-cf00-d652-3176547ae5ca@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Fri, Dec 28, 2018 at 03:25:10PM +0100, Paolo Bonzini wrote: Thanks a lot Paolo for the comments! I'll fix the issue in next version. > On 26/12/18 09:25, Yang Weijiang wrote: > > @@ -1233,6 +1252,14 @@ static const ExtSaveArea x86_ext_save_areas[] = { > > { .feature = FEAT_7_0_ECX, .bits = CPUID_7_0_ECX_PKU, > > .offset = offsetof(X86XSaveArea, pkru_state), > > .size = sizeof(XSavePKRU) }, > > + [XSTATE_CET_U_BIT] = { > > + .feature = FEAT_7_0_ECX, .bits = CPUID_7_0_ECX_CET_SHSTK, > > + .offset = offsetof(X86XSaveArea, cet_u), > > These offsets are incorrect, since supervisor states are only stored in > the compacted format. In fact, in patch 4, supervisor states should > return 0 in CPUID(EAX=0Dh,ECX=n).EBX. > > You can use offset == 0 to distinguish supervisor and user states, so > that supervisor states are skipped in xsave_area_size and x86_cpu_reset. > > Thanks, > > Paolo > > > + .size = sizeof(XSaveCETU) }, > > + [XSTATE_CET_S_BIT] = { > > + .feature = FEAT_7_0_ECX, .bits = CPUID_7_0_ECX_CET_SHSTK, > > + .offset = offsetof(X86XSaveArea, cet_s), > > + .size = sizeof(XSaveCETS) }, > > }; > > > > static uint32_t xsave_area_size(uint64_t mask)