From mboxrd@z Thu Jan 1 00:00:00 1970 From: Xiao Guangrong Subject: [PATCH v3 2/5] KVM: MMU: clarify the logic in kvm_set_pte_rmapp Date: Tue, 05 Feb 2013 16:53:52 +0800 Message-ID: <5110C8A0.5050405@linux.vnet.ibm.com> References: <5110C853.4080705@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , Gleb Natapov , LKML , KVM To: Xiao Guangrong Return-path: In-Reply-To: <5110C853.4080705@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org In kvm_set_pte_rmapp, if the new mapping is writable, we need to remove all spte pointing to that page otherwisewe we only need to adjust the sptes to let them point to the new page. This patch clarifys the logic and makes the later patch more clean [ Impact: no logic changed ] Signed-off-by: Xiao Guangrong --- arch/x86/kvm/mmu.c | 17 ++++++++--------- 1 files changed, 8 insertions(+), 9 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 68d4d5f..a0dc0d7 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -1225,16 +1225,16 @@ static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp, WARN_ON(pte_huge(*ptep)); new_pfn = pte_pfn(*ptep); - for (sptep = rmap_get_first(*rmapp, &iter); sptep;) { - BUG_ON(!is_shadow_present_pte(*sptep)); - rmap_printk("kvm_set_pte_rmapp: spte %p %llx\n", sptep, *sptep); + if (pte_write(*ptep)) + need_flush = kvm_unmap_rmapp(kvm, rmapp, slot, data); + else + for (sptep = rmap_get_first(*rmapp, &iter); sptep;) { + BUG_ON(!is_shadow_present_pte(*sptep)); + rmap_printk("kvm_set_pte_rmapp: spte %p %llx\n", + sptep, *sptep); - need_flush = 1; + need_flush = 1; - if (pte_write(*ptep)) { - drop_spte(kvm, sptep); - sptep = rmap_get_first(*rmapp, &iter); - } else { new_spte = *sptep & ~PT64_BASE_ADDR_MASK; new_spte |= (u64)new_pfn << PAGE_SHIFT; @@ -1246,7 +1246,6 @@ static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp, mmu_spte_set(sptep, new_spte); sptep = rmap_get_next(&iter); } - } if (need_flush) kvm_flush_remote_tlbs(kvm); -- 1.7.7.6