From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: [V7 3/4] x86/xsaves: enable xsaves/xrstors for hvm guest Date: Thu, 22 Oct 2015 15:26:02 +0100 Message-ID: <5628F1FA.1020909@citrix.com> References: <1445329285-4425-1-git-send-email-shuai.ruan@linux.intel.com> <1445329285-4425-4-git-send-email-shuai.ruan@linux.intel.com> <56290CB002000078000AD933@prv-mh.provo.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <56290CB002000078000AD933@prv-mh.provo.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich , Shuai Ruan Cc: kevin.tian@intel.com, wei.liu2@citrix.com, Ian.Campbell@citrix.com, stefano.stabellini@eu.citrix.com, eddie.dong@intel.com, ian.jackson@eu.citrix.com, xen-devel@lists.xen.org, jun.nakajima@intel.com, keir@xen.org List-Id: xen-devel@lists.xenproject.org On 22/10/15 15:20, Jan Beulich wrote: >>>> On 20.10.15 at 10:21, wrote: >> @@ -4784,6 +4804,13 @@ int hvm_msr_write_intercept(unsigned int msr, uint64_t msr_content, >> return X86EMUL_EXCEPTION; >> break; >> >> + case MSR_IA32_XSS: >> + /* No XSS features currently supported for guests. */ >> + if ( !cpu_has_xsaves || msr_content != 0 ) >> + goto gp_fault; >> + v->arch.hvm_vcpu.msr_xss = msr_content; >> + break; > Considering you add this write (and the msr_xss field in the first place) > despite it always being zero, I'd really like you to also add code > supporting save/restore of this new MSR. Or did I overlook something? I suppose that does mean that we don't strictly need interception/management of MSR_IA32_XSS yet, but it is ground work for the future work to enable Processor Trace for HVM guests. ~Andrew