From mboxrd@z Thu Jan 1 00:00:00 1970 From: Xiao Guangrong Subject: [PATCH v2 00/16] KVM: MMU: fast page fault Date: Fri, 13 Apr 2012 18:05:29 +0800 Message-ID: <4F87FA69.5060106@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , LKML , KVM To: Avi Kivity Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org Thanks for Avi and Marcelo's review, i have simplified the whole things in this version: - it only fix the page fault with PFEC.P = 1 && PFEC.W = 0 that means unlock set_spte path can be dropped. - it only fixes the page fault caused by dirty-log In this version, all the information we need is from spte, the SPTE_ALLOW_WRITE bit and SPTE_WRITE_PROTECT bit: - SPTE_ALLOW_WRITE is set if the gpte is writable and the pfn pointed by the spte is writable on host. - SPTE_WRITE_PROTECT is set if the spte is write-protected by shadow page table protection. All these bits can be protected by cmpxchg, now, all the things is fairly simple than before. :) Performance test: autotest migration: (Host: Intel(R) Xeon(R) CPU X5690 @ 3.47GHz * 12 + 32G) - For ept: Before: smp2.Fedora.16.64.migrate Times .unix .with_autotest.dbench.unix total 1 104 214 323 2 68 238 310 3 68 242 314 After: smp2.Fedora.16.64.migrate Times .unix .with_autotest.dbench.unix total 1 101 190 295 2 67 188 259 3 66 217 289 - For shadow mmu: Before: smp2.Fedora.16.64.migrate Times .unix .with_autotest.dbench.unix total 1 103 235 342 2 64 219 286 3 68 234 305 After: smp2.Fedora.16.64.migrate Times .unix .with_autotest.dbench.unix total 1 104 220 328 2 65 204 273 3 64 219 286