From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754148Ab3JWNaO (ORCPT ); Wed, 23 Oct 2013 09:30:14 -0400 Received: from e23smtp04.au.ibm.com ([202.81.31.146]:54719 "EHLO e23smtp04.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754092Ab3JWNaK (ORCPT ); Wed, 23 Oct 2013 09:30:10 -0400 From: Xiao Guangrong To: gleb@redhat.com Cc: avi.kivity@gmail.com, mtosatti@redhat.com, pbonzini@redhat.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Xiao Guangrong Subject: [PATCH v3 15/15] KVM: MMU: use rcu functions to access the pointer Date: Wed, 23 Oct 2013 21:29:33 +0800 Message-Id: <1382534973-13197-16-git-send-email-xiaoguangrong@linux.vnet.ibm.com> X-Mailer: git-send-email 1.8.1.4 In-Reply-To: <1382534973-13197-1-git-send-email-xiaoguangrong@linux.vnet.ibm.com> References: <1382534973-13197-1-git-send-email-xiaoguangrong@linux.vnet.ibm.com> X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13102313-9264-0000-0000-000004C92808 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Use rcu_assign_pointer() to update all the pointer in desc and use rcu_dereference() to lockless read the pointer Signed-off-by: Xiao Guangrong --- arch/x86/kvm/mmu.c | 46 ++++++++++++++++++++++++++++------------------ 1 file changed, 28 insertions(+), 18 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 3e4b941..68dac26 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -937,12 +937,23 @@ static void pte_list_desc_ctor(void *p) desc->more = NULL; } +#define rcu_assign_pte_list(pte_list_p, value) \ + rcu_assign_pointer(*(unsigned long __rcu **)(pte_list_p), \ + (unsigned long *)(value)) + +#define rcu_assign_desc_more(morep, value) \ + rcu_assign_pointer(*(unsigned long __rcu **)&morep, \ + (unsigned long *)value) + +#define rcu_assign_spte(sptep, value) \ + rcu_assign_pointer(*(u64 __rcu **)&sptep, (u64 *)value) + static void desc_mark_nulls(unsigned long *pte_list, struct pte_list_desc *desc) { unsigned long marker; marker = (unsigned long)pte_list | 1UL; - desc->more = (struct pte_list_desc *)marker; + rcu_assign_desc_more(desc->more, (struct pte_list_desc *)marker); } static bool desc_is_a_nulls(struct pte_list_desc *desc) @@ -999,10 +1010,6 @@ static int count_spte_number(struct pte_list_desc *desc) return first_free + desc_num * PTE_LIST_EXT; } -#define rcu_assign_pte_list(pte_list_p, value) \ - rcu_assign_pointer(*(unsigned long __rcu **)(pte_list_p), \ - (unsigned long *)(value)) - /* * Pte mapping structures: * @@ -1029,8 +1036,8 @@ static int pte_list_add(struct kvm_vcpu *vcpu, u64 *spte, if (!(*pte_list & 1)) { rmap_printk("pte_list_add: %p %llx 1->many\n", spte, *spte); desc = mmu_alloc_pte_list_desc(vcpu); - desc->sptes[0] = (u64 *)*pte_list; - desc->sptes[1] = spte; + rcu_assign_spte(desc->sptes[0], *pte_list); + rcu_assign_spte(desc->sptes[1], spte); desc_mark_nulls(pte_list, desc); rcu_assign_pte_list(pte_list, (unsigned long)desc | 1); return 1; @@ -1043,13 +1050,13 @@ static int pte_list_add(struct kvm_vcpu *vcpu, u64 *spte, if (desc->sptes[PTE_LIST_EXT - 1]) { struct pte_list_desc *new_desc; new_desc = mmu_alloc_pte_list_desc(vcpu); - new_desc->more = desc; + rcu_assign_desc_more(new_desc->more, desc); desc = new_desc; rcu_assign_pte_list(pte_list, (unsigned long)desc | 1); } free_pos = find_first_free(desc); - desc->sptes[free_pos] = spte; + rcu_assign_spte(desc->sptes[free_pos], spte); return count_spte_number(desc) - 1; } @@ -1067,8 +1074,8 @@ pte_list_desc_remove_entry(unsigned long *pte_list, * Move the entry from the first desc to this position we want * to remove. */ - desc->sptes[i] = first_desc->sptes[last_used]; - first_desc->sptes[last_used] = NULL; + rcu_assign_spte(desc->sptes[i], first_desc->sptes[last_used]); + rcu_assign_spte(first_desc->sptes[last_used], NULL); /* No valid entry in this desc, we can free this desc now. */ if (!first_desc->sptes[0]) { @@ -1080,7 +1087,7 @@ pte_list_desc_remove_entry(unsigned long *pte_list, WARN_ON(desc_is_a_nulls(next_desc)); mmu_free_pte_list_desc(first_desc); - *pte_list = (unsigned long)next_desc | 1ul; + rcu_assign_pte_list(pte_list, (unsigned long)next_desc | 1ul); return; } @@ -1089,8 +1096,8 @@ pte_list_desc_remove_entry(unsigned long *pte_list, * then the desc can be freed. */ if (!first_desc->sptes[1] && desc_is_a_nulls(first_desc->more)) { - *pte_list = (unsigned long)first_desc->sptes[0]; - first_desc->sptes[0] = NULL; + rcu_assign_pte_list(pte_list, first_desc->sptes[0]); + rcu_assign_spte(first_desc->sptes[0], NULL); mmu_free_pte_list_desc(first_desc); } } @@ -1112,7 +1119,7 @@ static void pte_list_remove(u64 *spte, unsigned long *pte_list) pr_err("pte_list_remove: %p 1->BUG\n", spte); BUG(); } - *pte_list = 0; + rcu_assign_pte_list(pte_list, 0); return; } @@ -1184,9 +1191,12 @@ restart: * used in the rmap when a spte is removed. Otherwise the * moved entry will be missed. */ - for (i = PTE_LIST_EXT - 1; i >= 0; i--) - if (desc->sptes[i]) - fn(desc->sptes[i]); + for (i = PTE_LIST_EXT - 1; i >= 0; i--) { + u64 *sptep = rcu_dereference(desc->sptes[i]); + + if (sptep) + fn(sptep); + } desc = rcu_dereference(desc->more); -- 1.8.1.4