From patchwork Mon Feb 8 11:22:50 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yanan Wang X-Patchwork-Id: 12075127 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=-17.3 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 0E198C433E9 for ; Mon, 8 Feb 2021 11:24:21 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 8990864E30 for ; Mon, 8 Feb 2021 11:24:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8990864E30 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=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-ID:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=DSBp7LWrxI4E4EXyr5PF4cw44xbMuoc2WanhVZZc8M0=; b=iloggH2LzaFpemBMYdC7OV4BT uRdjQAJvqkQHZWSSvxA6D8RhdHpC3yyP6XqHanHZalPY7ZJEEE2rXsNSu5apjiHQlToZ9Krr5IOFM Z39wG3N6Ots6acuK8zCEOm1la+Kc2KaYoZENS/MbLC09BJObHwVxoQ9c+MPTuq4hjxuNzLgHTpUin d1fdXXvK/AHyB116rknRwJngMwrHp5hRxlAjc5q3Rraxr+ycxc9jED9gtUQeMkDSk7AUuqHY2wVU1 zwJ+XiSNQqx2BTh0iI5u/wY8vAbWbFg3quoNsXVNgD536vIAWkx2iHCTPHoFY5oI5cOWYhZRUodrI knQ3AIkUw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l94dR-0006i7-OG; Mon, 08 Feb 2021 11:23:17 +0000 Received: from szxga04-in.huawei.com ([45.249.212.190]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1l94dI-0006eL-Dc for linux-arm-kernel@lists.infradead.org; Mon, 08 Feb 2021 11:23:09 +0000 Received: from DGGEMS411-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4DZ3W558lPzlHb3; Mon, 8 Feb 2021 19:21:21 +0800 (CST) Received: from DESKTOP-TMVL5KK.china.huawei.com (10.174.187.128) by DGGEMS411-HUB.china.huawei.com (10.3.19.211) with Microsoft SMTP Server id 14.3.498.0; Mon, 8 Feb 2021 19:22:57 +0800 From: Yanan Wang To: Marc Zyngier , Will Deacon , "Catalin Marinas" , James Morse , "Julien Thierry" , Suzuki K Poulose , Gavin Shan , Quentin Perret , , , , Subject: [RFC PATCH 4/4] KVM: arm64: Distinguish cases of memcache allocations completely Date: Mon, 8 Feb 2021 19:22:50 +0800 Message-ID: <20210208112250.163568-5-wangyanan55@huawei.com> X-Mailer: git-send-email 2.8.4.windows.1 In-Reply-To: <20210208112250.163568-1-wangyanan55@huawei.com> References: <20210208112250.163568-1-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-20210208_062308_724684_C17A16AF X-CRM114-Status: GOOD ( 15.71 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: yuzenghui@huawei.com, wanghaibin.wang@huawei.com, Yanan Wang , zhukeqian1@huawei.com 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 d151927a7d62..550498a9104e 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -815,19 +815,6 @@ 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 @@ -887,6 +874,18 @@ 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,