From patchwork Tue Aug 16 06:40:40 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiao Guangrong X-Patchwork-Id: 1070522 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter2.kernel.org (8.14.4/8.14.4) with ESMTP id p7G6cwwL006304 for ; Tue, 16 Aug 2011 06:38:58 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751208Ab1HPGim (ORCPT ); Tue, 16 Aug 2011 02:38:42 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:54298 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751143Ab1HPGil (ORCPT ); Tue, 16 Aug 2011 02:38:41 -0400 Received: from tang.cn.fujitsu.com (tang.cn.fujitsu.com [10.167.250.3]) by song.cn.fujitsu.com (Postfix) with ESMTP id 96F66170141; Tue, 16 Aug 2011 14:38:39 +0800 (CST) Received: from mailserver.fnst.cn.fujitsu.com (tang.cn.fujitsu.com [127.0.0.1]) by tang.cn.fujitsu.com (8.14.3/8.13.1) with ESMTP id p7G6cb9A000816; Tue, 16 Aug 2011 14:38:38 +0800 Received: from localhost.localdomain ([10.167.225.99]) by mailserver.fnst.cn.fujitsu.com (Lotus Domino Release 8.5.1FP4) with ESMTP id 2011081614372945-20429 ; Tue, 16 Aug 2011 14:37:29 +0800 Message-ID: <4E4A10E8.5090705@cn.fujitsu.com> Date: Tue, 16 Aug 2011 14:40:40 +0800 From: Xiao Guangrong User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110428 Fedora/3.1.10-1.fc15 Thunderbird/3.1.10 MIME-Version: 1.0 To: Avi Kivity CC: Marcelo Tosatti , LKML , KVM Subject: [PATCH 01/11] KVM: MMU: avoid pte_list_desc running out in kvm_mmu_pte_write X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-08-16 14:37:29, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-08-16 14:37:31, Serialize complete at 2011-08-16 14:37:31 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter2.kernel.org [140.211.167.43]); Tue, 16 Aug 2011 06:38:58 +0000 (UTC) kvm_mmu_pte_write is unsafe since we need to alloc pte_list_desc in the function when spte is prefetched, unfortunately, we can not know how many spte need to be prefetched on this path, that means we can use out of the free pte_list_desc object in the cache, and BUG_ON() is triggered, also some path does not fill the cache, such as INS instruction emulated that does not trigger page fault Signed-off-by: Xiao Guangrong --- arch/x86/kvm/mmu.c | 25 ++++++++++++++++++++----- 1 files changed, 20 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 5d7fbf0..b01afee 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -592,6 +592,11 @@ static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache, return 0; } +static int mmu_memory_cache_free_objects(struct kvm_mmu_memory_cache *cache) +{ + return cache->nobjs; +} + static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc, struct kmem_cache *cache) { @@ -969,6 +974,14 @@ static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int level) return &linfo->rmap_pde; } +static bool rmap_can_add(struct kvm_vcpu *vcpu) +{ + struct kvm_mmu_memory_cache *cache; + + cache = &vcpu->arch.mmu_pte_list_desc_cache; + return mmu_memory_cache_free_objects(cache); +} + static int rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn) { struct kvm_mmu_page *sp; @@ -3585,6 +3598,12 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa, break; } + /* + * No need to care whether allocation memory is successful + * or not since pte prefetch is skiped if it does not have + * enough objects in the cache. + */ + mmu_topup_memory_caches(vcpu); spin_lock(&vcpu->kvm->mmu_lock); if (atomic_read(&vcpu->kvm->arch.invlpg_counter) != invlpg_counter) gentry = 0; @@ -3655,7 +3674,7 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa, mmu_page_zap_pte(vcpu->kvm, sp, spte); if (gentry && !((sp->role.word ^ vcpu->arch.mmu.base_role.word) - & mask.word)) + & mask.word) && rmap_can_add(vcpu)) mmu_pte_write_new_pte(vcpu, sp, spte, &gentry); if (!remote_flush && need_remote_flush(entry, *spte)) remote_flush = true; @@ -3716,10 +3735,6 @@ int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code, goto out; } - r = mmu_topup_memory_caches(vcpu); - if (r) - goto out; - er = x86_emulate_instruction(vcpu, cr2, 0, insn, insn_len); switch (er) {