From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jan Beulich" Subject: Re: [PATCH v3 03/13] VMX: implement suppress #VE. Date: Mon, 13 Jul 2015 08:40:05 +0100 Message-ID: <55A38775020000780008FF35@mail.emea.novell.com> References: <1435774177-6345-1-git-send-email-edmund.h.white@intel.com> <1435774177-6345-4-git-send-email-edmund.h.white@intel.com> <559E8CAF020000780008EC87@mail.emea.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: 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: Ravi Sahita Cc: Tim Deegan , Wei Liu , George Dunlap , Andrew Cooper , Ian Jackson , Edmund H White , "xen-devel@lists.xen.org" , "tlengyel@novetta.com" , Daniel De Graaf List-Id: xen-devel@lists.xenproject.org >>> On 10.07.15 at 21:30, wrote: >> From: Jan Beulich [mailto:JBeulich@suse.com] >>Sent: Thursday, July 09, 2015 6:01 AM >>>>> On 01.07.15 at 20:09, wrote: >>> @@ -232,6 +235,15 @@ static int ept_set_middle_entry(struct p2m_domain >>> @@ -1134,6 +1151,13 @@ int ept_p2m_init(struct p2m_domain *p2m) >>> p2m->flush_hardware_cached_dirty = ept_flush_pml_buffers; >>> } >>> >>> + table = >>> + map_domain_page(pagetable_get_pfn(p2m_get_pagetable(p2m))); >>> + >>> + for ( i = 0; i < EPT_PAGETABLE_ENTRIES; i++ ) >>> + table[i].suppress_ve = 1; >>> + >>> + unmap_domain_page(table); >> >>... why is this needed? Bit 63 is documented to be ignored in PML4Es (just > like >>in all other intermediate page tables). > > Valid point - this has no negative side-effects per se so we didn't change > this. Taking "we didn't change this" to refer to v3 -> v4, I still think this should be dropped if it isn't needed. There can only be confusion arising from code having no purpose. Jan