From patchwork Tue Nov 29 19:19:44 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oliver Upton X-Patchwork-Id: 13059064 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 848FCC433FE for ; Tue, 29 Nov 2022 19:24:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; 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=k8+GQe2mrpvIjbYIKP8E2UrW7fcEqb4Dbn8/gAQSwDo=; b=IyGlCRV+YGvgb4 TVAJ5yaWoMmTeBQDj6wCP0xnLuj+hBtf/uQ6FEtK0fT4LCkNsrC5C3Q7zXz8xGZfi5dR/FYjMqq/6 DSzwxCBUv888zZn6xZsPvTETuLSEZ1qONYcXt8TGRBYwplhHYelW7SPnpFMQN+YazZHO84PjopFPb eQC/VvNpXk24gd62xZg12aLRxXZhFnuKXBg2pbxDHmMvb8l4P7shD7o0nINJJT5uIs6WaxunYma2t +jQ6k4ABTJ2K3BFfM+dG9mJ/M39WtaGFvbypKbGUdPTLjjdp34nl+TFA4rC33S0Wmph8MpLz3gMKD zaDh5p4Yiu9qgrn8oJzw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1p06CP-00B28w-3M; Tue, 29 Nov 2022 19:23:21 +0000 Received: from out2.migadu.com ([188.165.223.204]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1p069O-00Azvv-Sv for linux-arm-kernel@lists.infradead.org; Tue, 29 Nov 2022 19:20:17 +0000 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=1669749599; 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=gZ4zOeCGbv1gvItGbIIGPQNuQz+qC/NQiSdoYbMqOcA=; b=ivgJME643G8i5ESEr5NCoBRxVONgW7xNcfo9eS52aTmAiibYNqYar1tSVUGNHBZlpVpKsW fZVLO+TVjMk1oxRvpreTbTajXlBarEJAum8hCMBQG4qntEG7Y43uEXKfviUFRYDfwDIrMV rRTPphdF0qeiMRSwSaQinxn6tNZH9jk= 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, linux-kernel@vger.kernel.org Subject: [PATCH 2/4] KVM: arm64: Don't serialize if the access flag isn't set Date: Tue, 29 Nov 2022 19:19:44 +0000 Message-Id: <20221129191946.1735662-3-oliver.upton@linux.dev> In-Reply-To: <20221129191946.1735662-1-oliver.upton@linux.dev> References: <20221129191946.1735662-1-oliver.upton@linux.dev> MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221129_112015_149063_86AFE20B X-CRM114-Status: UNSURE ( 9.23 ) X-CRM114-Notice: Please train this message. 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 Of course, if the PTE wasn't changed then there are absolutely no serialization requirements. Skip the DSB for an unsuccessful update to the access flag. Signed-off-by: Oliver Upton --- arch/arm64/kvm/hyp/pgtable.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index b11cf2c618a6..9626f615d9b8 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -1094,9 +1094,13 @@ int kvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size) kvm_pte_t kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr) { kvm_pte_t pte = 0; - stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0, - &pte, NULL, 0); - dsb(ishst); + int ret; + + ret = stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0, + &pte, NULL, 0); + if (!ret) + dsb(ishst); + return pte; }