From patchwork Fri Dec 2 18:51:55 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oliver Upton X-Patchwork-Id: 13063138 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9AEE2C4321E for ; Fri, 2 Dec 2022 18:52:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234739AbiLBSwm (ORCPT ); Fri, 2 Dec 2022 13:52:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39752 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234347AbiLBSwg (ORCPT ); Fri, 2 Dec 2022 13:52:36 -0500 Received: from out-242.mta0.migadu.com (out-242.mta0.migadu.com [IPv6:2001:41d0:1004:224b::f2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5B490ECA2A for ; Fri, 2 Dec 2022 10:52:28 -0800 (PST) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1670007146; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=36q34GkAdZNcp02VfFJ/fMceb+GlTAxgwL6t8UJ/nCU=; b=LAPfFRXkfCOfssjRADm7/jdYZ7LQl2uW9dy14PfWeo2914srk2DSSW7OAI1GrB7JEscgbY DxllYbdQAX26FIFaFFLzCntc4Uhua5fSy2WeUOjvTWcv81z6joZgp064csO8ICW67kHF+9 cSAdicod8mmQR59+MNnYmUOZe79b8Wc= From: Oliver Upton To: Marc Zyngier , James Morse , Alexandru Elisei , Suzuki K Poulose , Oliver Upton , Catalin Marinas , Will Deacon Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, kvmarm@lists.linux.dev, Ricardo Koller , linux-kernel@vger.kernel.org Subject: [PATCH v2 5/6] KVM: arm64: Handle access faults behind the read lock Date: Fri, 2 Dec 2022 18:51:55 +0000 Message-Id: <20221202185156.696189-6-oliver.upton@linux.dev> In-Reply-To: <20221202185156.696189-1-oliver.upton@linux.dev> References: <20221202185156.696189-1-oliver.upton@linux.dev> MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org As the underlying software walkers are able to traverse and update stage-2 in parallel there is no need to serialize access faults. Only take the read lock when handling an access fault. Signed-off-by: Oliver Upton --- arch/arm64/kvm/hyp/pgtable.c | 3 ++- arch/arm64/kvm/mmu.c | 4 ++-- 2 files changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index aa36d896bd8c..30575b5f5dcd 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -1120,7 +1120,8 @@ kvm_pte_t kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr) ret = stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0, &pte, NULL, - KVM_PGTABLE_WALK_HANDLE_FAULT); + KVM_PGTABLE_WALK_HANDLE_FAULT | + KVM_PGTABLE_WALK_SHARED); if (!ret) dsb(ishst); diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index dd8c715f0775..25e18e1d9a15 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1406,10 +1406,10 @@ static void handle_access_fault(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa) trace_kvm_access_fault(fault_ipa); - write_lock(&vcpu->kvm->mmu_lock); + read_lock(&vcpu->kvm->mmu_lock); mmu = vcpu->arch.hw_mmu; pte = kvm_pgtable_stage2_mkyoung(mmu->pgt, fault_ipa); - write_unlock(&vcpu->kvm->mmu_lock); + read_unlock(&vcpu->kvm->mmu_lock); if (kvm_pte_valid(pte)) kvm_set_pfn_accessed(kvm_pte_to_pfn(pte));