From patchwork Wed Mar 10 09:43:19 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yanan Wang X-Patchwork-Id: 12127441 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=-17.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 1191DC433E0 for ; Wed, 10 Mar 2021 09:45:23 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 88ECB64FBF for ; Wed, 10 Mar 2021 09:45:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 88ECB64FBF Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-ID:Date: Subject:CC:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=fp37d8Og48iXPEwfNsbotTNEb8dRxUj0bN2o3LHq9Io=; b=DbiPJDUG8hxB2Mz93+NJgUWA9 VN9x3bYfTDLYzXqna6lwfoUZEQksx+NRuo8ZyDpOYqy2krujR28w6HWbCleOu4mMQfE3lYoQwyC5T yl91Y8FoJARlnTdUfV7X5HwnVAI4C9xm1WZxDEFOdYLhGR6GlUXky0iwmDtUOwG85oT8JBWKoEXZI dvYryaiRdc4dQCOGhiB9xI9K+V8vqWyz+aDWUANmJLINzykSVQSiPMHqPvCLtm3ssQLYJXx9S42VZ 8tfsX4EiTbARm60g9oWO5ur71ZecCPU/pY7yRolT4sTA/7Ylja5z7QsAZBefuobn2y3V1u7APDHAd dlVgVO4TA==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lJvNk-006U9O-BM; Wed, 10 Mar 2021 09:43:56 +0000 Received: from szxga04-in.huawei.com ([45.249.212.190]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lJvNV-006U4L-8Q for linux-arm-kernel@lists.infradead.org; Wed, 10 Mar 2021 09:43:43 +0000 Received: from DGGEMS412-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4DwRtN0Syxz17J2q; Wed, 10 Mar 2021 17:41:48 +0800 (CST) Received: from DESKTOP-TMVL5KK.china.huawei.com (10.174.187.128) by DGGEMS412-HUB.china.huawei.com (10.3.19.212) with Microsoft SMTP Server id 14.3.498.0; Wed, 10 Mar 2021 17:43:25 +0800 From: Yanan Wang To: Marc Zyngier , Will Deacon , "Catalin Marinas" , James Morse , "Julien Thierry" , Suzuki K Poulose , Gavin Shan , Quentin Perret , , , , CC: , , , Yanan Wang Subject: [RFC PATCH v2 3/3] KVM: arm64: Distinguish cases of memcache allocations completely Date: Wed, 10 Mar 2021 17:43:19 +0800 Message-ID: <20210310094319.18760-4-wangyanan55@huawei.com> X-Mailer: git-send-email 2.8.4.windows.1 In-Reply-To: <20210310094319.18760-1-wangyanan55@huawei.com> References: <20210310094319.18760-1-wangyanan55@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.174.187.128] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210310_094341_716174_B5420E33 X-CRM114-Status: GOOD ( 17.45 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.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 1eec9f63bc6f..05af40dc60c1 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -810,19 +810,6 @@ 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 @@ -880,6 +867,18 @@ 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,