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[23.128.96.18]) by mx.google.com with ESMTP id b14si2122958ede.509.2021.05.12.06.34.15; Wed, 12 May 2021 06:34:39 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=huawei.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233398AbhELM5S (ORCPT + 99 others); Wed, 12 May 2021 08:57:18 -0400 Received: from szxga03-in.huawei.com ([45.249.212.189]:2365 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233638AbhELMz6 (ORCPT ); Wed, 12 May 2021 08:55:58 -0400 Received: from dggeml711-chm.china.huawei.com (unknown [172.30.72.56]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4FgF621Fldz5vvL; Wed, 12 May 2021 20:51:22 +0800 (CST) Received: from dggpemm500023.china.huawei.com (7.185.36.83) by dggeml711-chm.china.huawei.com (10.3.17.122) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Wed, 12 May 2021 20:54:44 +0800 Received: from [10.174.187.128] (10.174.187.128) by dggpemm500023.china.huawei.com (7.185.36.83) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2176.2; Wed, 12 May 2021 20:54:43 +0800 Subject: Re: [PATCH v5 0/6] KVM: arm64: Improve efficiency of stage2 page table To: Marc Zyngier , Will Deacon , "Quentin Perret" , Alexandru Elisei , , , , CC: Catalin Marinas , James Morse , Julien Thierry , "Suzuki K Poulose" , Gavin Shan , , , References: <20210415115032.35760-1-wangyanan55@huawei.com> From: "wangyanan (Y)" Message-ID: Date: Wed, 12 May 2021 20:54:43 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: <20210415115032.35760-1-wangyanan55@huawei.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Originating-IP: [10.174.187.128] X-ClientProxiedBy: dggeme705-chm.china.huawei.com (10.1.199.101) To dggpemm500023.china.huawei.com (7.185.36.83) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org A really gentle ping ... Sincerely, Yanan On 2021/4/15 19:50, Yanan Wang wrote: > Hi, > > This series makes some efficiency improvement of guest stage-2 page > table code, and there are some test results to quantify the benefit. > The code has been re-arranged based on the latest kvmarm/next tree. > > Descriptions: > We currently uniformly permorm CMOs of D-cache and I-cache in function > user_mem_abort before calling the fault handlers. If we get concurrent > guest faults(e.g. translation faults, permission faults) or some really > unnecessary guest faults caused by BBM, CMOs for the first vcpu are > necessary while the others later are not. > > By moving CMOs to the fault handlers, we can easily identify conditions > where they are really needed and avoid the unnecessary ones. As it's a > time consuming process to perform CMOs especially when flushing a block > range, so this solution reduces much load of kvm and improve efficiency > of the stage-2 page table code. > > In this series, patch #1, #3, #4 make preparation for place movement > of CMOs (adapt to the latest stage-2 page table framework). And patch > #2, #5 move CMOs of D-cache and I-cache to the fault handlers. Patch > #6 introduces a new way to distinguish cases of memcache allocations. > > The following are results in v3 to represent the benefit introduced > by movement of CMOs, and they were tested by [1] (kvm/selftest) that > I have posted recently. > [1] https://lore.kernel.org/lkml/20210302125751.19080-1-wangyanan55@huawei.com/ > > When there are muitiple vcpus concurrently accessing the same memory > region, we can test the execution time of KVM creating new mappings, > updating the permissions of old mappings from RO to RW, and the time > of re-creating the blocks after they have been split. > > hardware platform: HiSilicon Kunpeng920 Server > host kernel: Linux mainline v5.12-rc2 > > cmdline: ./kvm_page_table_test -m 4 -s anonymous -b 1G -v 80 > (80 vcpus, 1G memory, page mappings(normal 4K)) > KVM_CREATE_MAPPINGS: before 104.35s -> after 90.42s +13.35% > KVM_UPDATE_MAPPINGS: before 78.64s -> after 75.45s + 4.06% > > cmdline: ./kvm_page_table_test -m 4 -s anonymous_thp -b 20G -v 40 > (40 vcpus, 20G memory, block mappings(THP 2M)) > KVM_CREATE_MAPPINGS: before 15.66s -> after 6.92s +55.80% > KVM_UPDATE_MAPPINGS: before 178.80s -> after 123.35s +31.00% > KVM_REBUILD_BLOCKS: before 187.34s -> after 131.76s +30.65% > > cmdline: ./kvm_page_table_test -m 4 -s anonymous_hugetlb_1gb -b 20G -v 40 > (40 vcpus, 20G memory, block mappings(HUGETLB 1G)) > KVM_CREATE_MAPPINGS: before 104.54s -> after 3.70s +96.46% > KVM_UPDATE_MAPPINGS: before 174.20s -> after 115.94s +33.44% > KVM_REBUILD_BLOCKS: before 103.95s -> after 2.96s +97.15% > > --- > > Changelogs: > v4->v5: > - rebased on the latest kvmarm/tree to adapt to the new stage-2 page-table code > - v4: https://lore.kernel.org/lkml/20210409033652.28316-1-wangyanan55@huawei.com/ > > v3->v4: > - perform D-cache flush if we are not mapping device memory > - rebased on top of mainline v5.12-rc6 > - v3: https://lore.kernel.org/lkml/20210326031654.3716-1-wangyanan55@huawei.com/ > > v2->v3: > - drop patch #3 in v2 > - retest v3 based on v5.12-rc2 > - v2: https://lore.kernel.org/lkml/20210310094319.18760-1-wangyanan55@huawei.com/ > > v1->v2: > - rebased on top of mainline v5.12-rc2 > - also move CMOs of I-cache to the fault handlers > - retest v2 based on v5.12-rc2 > - v1: https://lore.kernel.org/lkml/20210208112250.163568-1-wangyanan55@huawei.com/ > > --- > > Yanan Wang (6): > KVM: arm64: Introduce KVM_PGTABLE_S2_GUEST stage-2 flag > KVM: arm64: Move D-cache flush to the fault handlers > KVM: arm64: Add mm_ops member for structure stage2_attr_data > KVM: arm64: Provide invalidate_icache_range at non-VHE EL2 > KVM: arm64: Move I-cache flush to the fault handlers > KVM: arm64: Distinguish cases of memcache allocations completely > > arch/arm64/include/asm/kvm_mmu.h | 31 ------------- > arch/arm64/include/asm/kvm_pgtable.h | 38 ++++++++++------ > arch/arm64/kvm/hyp/nvhe/cache.S | 11 +++++ > arch/arm64/kvm/hyp/pgtable.c | 65 +++++++++++++++++++++++----- > arch/arm64/kvm/mmu.c | 51 ++++++++-------------- > 5 files changed, 107 insertions(+), 89 deletions(-) >