From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jan Beulich" Subject: Re: [v3] libxc: Expose the 1GB pages cpuid flag to guest Date: Fri, 28 Nov 2014 09:16:18 +0000 Message-ID: <54784B72020000780004B565@mail.emea.novell.com> References: <1417145320-9158-1-git-send-email-liang.z.li@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1417145320-9158-1-git-send-email-liang.z.li@intel.com> Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Liang Li Cc: tim@xen.org, wei.liu2@citrix.com, ian.campbell@citrix.com, stefano.stabellini@eu.citrix.com, andrew.cooper3@citrix.com, ian.jackson@eu.citrix.com, xen-devel@lists.xen.org, yang.z.zhang@intel.com List-Id: xen-devel@lists.xenproject.org >>> On 28.11.14 at 04:28, wrote: > --- a/xen/arch/x86/hvm/hvm.c > +++ b/xen/arch/x86/hvm/hvm.c > @@ -4287,7 +4287,7 @@ void hvm_cpuid(unsigned int input, unsigned int *eax, unsigned int *ebx, > !host_tsc_is_safe() ) > *edx &= ~cpufeat_mask(X86_FEATURE_RDTSCP); > /* Hide 1GB-superpage feature if we can't emulate it. */ > - if (!hvm_pse1gb_supported(d)) > + if (!hvm_pse1gb_supported(d) || paging_mode_shadow(d)) > *edx &= ~cpufeat_mask(X86_FEATURE_PAGE1GB); With #define hvm_pse1gb_supported(d) \ (cpu_has_page1gb && paging_mode_hap(d)) the change above is pointless. While, considering this, comments on v2 may have been misleading, you should have simply updated the patch description instead to clarify why the v2 change was okay even for the shadow mode case. Jan