Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755923Ab3G3NJ7 (ORCPT ); Tue, 30 Jul 2013 09:09:59 -0400 Received: from e28smtp01.in.ibm.com ([122.248.162.1]:51686 "EHLO e28smtp01.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755389Ab3G3NHv (ORCPT ); Tue, 30 Jul 2013 09:07:51 -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 08/12] KVM: MMU: introduce nulls desc Date: Tue, 30 Jul 2013 21:02:06 +0800 Message-Id: <1375189330-24066-9-git-send-email-xiaoguangrong@linux.vnet.ibm.com> X-Mailer: git-send-email 1.8.1.4 In-Reply-To: <1375189330-24066-1-git-send-email-xiaoguangrong@linux.vnet.ibm.com> References: <1375189330-24066-1-git-send-email-xiaoguangrong@linux.vnet.ibm.com> X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13073012-4790-0000-0000-00000988A7DF Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4026 Lines: 123 It likes nulls list and we use the pte-list as the nulls which can help us to detect whether the "desc" is moved to anther rmap then we can re-walk the rmap if that happened Signed-off-by: Xiao Guangrong --- arch/x86/kvm/mmu.c | 35 ++++++++++++++++++++++++++++------- 1 file changed, 28 insertions(+), 7 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 3013bb1..36caf6a 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -918,6 +918,24 @@ static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn) return level - 1; } +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; +} + +static bool desc_is_a_nulls(struct pte_list_desc *desc) +{ + return (unsigned long)desc & 1; +} + +static unsigned long *desc_get_nulls_value(struct pte_list_desc *desc) +{ + return (unsigned long *)((unsigned long)desc & ~1); +} + static int __find_first_free(struct pte_list_desc *desc) { int i; @@ -956,7 +974,7 @@ static int count_spte_number(struct pte_list_desc *desc) first_free = __find_first_free(desc); - for (desc_num = 0; desc->more; desc = desc->more) + for (desc_num = 0; !desc_is_a_nulls(desc->more); desc = desc->more) desc_num++; return first_free + desc_num * PTE_LIST_EXT; @@ -991,6 +1009,7 @@ static int pte_list_add(struct kvm_vcpu *vcpu, u64 *spte, desc = mmu_alloc_pte_list_desc(vcpu); desc->sptes[0] = (u64 *)*pte_list; desc->sptes[1] = spte; + desc_mark_nulls(pte_list, desc); *pte_list = (unsigned long)desc | 1; return 1; } @@ -1036,7 +1055,7 @@ pte_list_desc_remove_entry(unsigned long *pte_list, /* * Only one entry existing but still use a desc to store it? */ - WARN_ON(!next_desc); + WARN_ON(desc_is_a_nulls(next_desc)); mmu_free_pte_list_desc(first_desc); first_desc = next_desc; @@ -1050,7 +1069,7 @@ pte_list_desc_remove_entry(unsigned long *pte_list, * Only one entry in this desc, move the entry to the head * then the desc can be freed. */ - if (!first_desc->sptes[1] && !first_desc->more) { + if (!first_desc->sptes[1] && desc_is_a_nulls(first_desc->more)) { *pte_list = (unsigned long)first_desc->sptes[0]; mmu_free_pte_list_desc(first_desc); } @@ -1077,7 +1096,7 @@ static void pte_list_remove(u64 *spte, unsigned long *pte_list) rmap_printk("pte_list_remove: %p many->many\n", spte); desc = (struct pte_list_desc *)(*pte_list & ~1ul); - while (desc) { + while (!desc_is_a_nulls(desc)) { for (i = 0; i < PTE_LIST_EXT && desc->sptes[i]; ++i) if (desc->sptes[i] == spte) { pte_list_desc_remove_entry(pte_list, @@ -1103,11 +1122,13 @@ static void pte_list_walk(unsigned long *pte_list, pte_list_walk_fn fn) return fn((u64 *)*pte_list); desc = (struct pte_list_desc *)(*pte_list & ~1ul); - while (desc) { + while (!desc_is_a_nulls(desc)) { for (i = 0; i < PTE_LIST_EXT && desc->sptes[i]; ++i) fn(desc->sptes[i]); desc = desc->more; } + + WARN_ON(desc_get_nulls_value(desc) != pte_list); } static unsigned long *__gfn_to_rmap(gfn_t gfn, int level, @@ -1200,7 +1221,7 @@ static u64 *rmap_get_first(unsigned long rmap, struct rmap_iterator *iter) */ static u64 *rmap_get_next(struct rmap_iterator *iter) { - if (iter->desc) { + if (iter->desc && !desc_is_a_nulls(iter->desc)) { if (iter->pos < PTE_LIST_EXT - 1) { u64 *sptep; @@ -1212,7 +1233,7 @@ static u64 *rmap_get_next(struct rmap_iterator *iter) iter->desc = iter->desc->more; - if (iter->desc) { + if (!desc_is_a_nulls(iter->desc)) { iter->pos = 0; /* desc->sptes[0] cannot be NULL */ return iter->desc->sptes[iter->pos]; -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/