From patchwork Thu Apr 15 11:50:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yanan Wang X-Patchwork-Id: 12205215 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 58B5BC433ED for ; Thu, 15 Apr 2021 11:51:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2CCC0613B0 for ; Thu, 15 Apr 2021 11:51:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232836AbhDOLvY (ORCPT ); Thu, 15 Apr 2021 07:51:24 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:16923 "EHLO szxga06-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232682AbhDOLvQ (ORCPT ); Thu, 15 Apr 2021 07:51:16 -0400 Received: from DGGEMS407-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga06-in.huawei.com (SkyGuard) with ESMTP id 4FLd0W4RGXzlXKt; Thu, 15 Apr 2021 19:48:59 +0800 (CST) Received: from DESKTOP-TMVL5KK.china.huawei.com (10.174.187.128) by DGGEMS407-HUB.china.huawei.com (10.3.19.207) with Microsoft SMTP Server id 14.3.498.0; Thu, 15 Apr 2021 19:50:41 +0800 From: Yanan Wang To: Marc Zyngier , Will Deacon , "Quentin Perret" , Alexandru Elisei , , , , CC: Catalin Marinas , James Morse , Julien Thierry , "Suzuki K Poulose" , Gavin Shan , , , , Yanan Wang Subject: [PATCH v5 6/6] KVM: arm64: Distinguish cases of memcache allocations completely Date: Thu, 15 Apr 2021 19:50:32 +0800 Message-ID: <20210415115032.35760-7-wangyanan55@huawei.com> X-Mailer: git-send-email 2.8.4.windows.1 In-Reply-To: <20210415115032.35760-1-wangyanan55@huawei.com> References: <20210415115032.35760-1-wangyanan55@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.174.187.128] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org With a guest translation fault, the memcache pages are not needed if KVM is only about to install a new leaf entry into the existing page table. And with a guest permission fault, the memcache pages are also not needed for a write_fault in dirty-logging time if KVM is only about to update the existing leaf entry instead of collapsing a block entry into a table. By comparing fault_granule and vma_pagesize, cases that require allocations from memcache and cases that don't can be distinguished completely. Signed-off-by: Yanan Wang --- arch/arm64/kvm/mmu.c | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index aa536392b308..9e35aa5d29f2 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -895,19 +895,6 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, gfn = fault_ipa >> PAGE_SHIFT; mmap_read_unlock(current->mm); - /* - * Permission faults just need to update the existing leaf entry, - * and so normally don't require allocations from the memcache. The - * only exception to this is when dirty logging is enabled at runtime - * and a write fault needs to collapse a block entry into a table. - */ - if (fault_status != FSC_PERM || (logging_active && write_fault)) { - ret = kvm_mmu_topup_memory_cache(memcache, - kvm_mmu_cache_min_pages(kvm)); - if (ret) - return ret; - } - mmu_seq = vcpu->kvm->mmu_notifier_seq; /* * Ensure the read of mmu_notifier_seq happens before we call @@ -970,6 +957,18 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, else if (cpus_have_const_cap(ARM64_HAS_CACHE_DIC)) prot |= KVM_PGTABLE_PROT_X; + /* + * Allocations from the memcache are required only when granule of the + * lookup level where the guest fault happened exceeds vma_pagesize, + * which means new page tables will be created in the fault handlers. + */ + if (fault_granule > vma_pagesize) { + ret = kvm_mmu_topup_memory_cache(memcache, + kvm_mmu_cache_min_pages(kvm)); + if (ret) + return ret; + } + /* * Under the premise of getting a FSC_PERM fault, we just need to relax * permissions only if vma_pagesize equals fault_granule. Otherwise,