From patchwork Mon Sep 3 13:45:13 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoffer Dall X-Patchwork-Id: 10585955 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8E10D175A for ; Mon, 3 Sep 2018 13:46:53 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7DBD82981E for ; Mon, 3 Sep 2018 13:46:53 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7122B2982A; Mon, 3 Sep 2018 13:46:53 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 110512981E for ; Mon, 3 Sep 2018 13:46:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: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=eV97lX9cYJruxG6CeEvZc2hqIa4oEctYZKahUfMWEls=; b=RoHUMMWsmoa1u/0KDVJpM7tUAK 7VFtDj7gBJLnmDgq9d+WlRv7eASzbsaj0OjNBB8BrS9aRMESbOs9pBIQjxPSKa9oUutaBsALjVRSS dEbu22fsndQne0NjOLPfvwqNqnJeZyKqBQEsFI7pWWitCle+njWzjtanCW8NlRUashLAk1xjj7Ah1 SgSXKYpyZITV8eloQrCRYyf0u+BeE0+xJq+/KmEuWddb/2dteB3irBmy+20sqhGVsqhxitLkYgzEo n7a3aJoDqTxpRYFymnb0Vp1S5u/CpyI4zkFc1yRwZsyXNYXY5HxyaMc69ZMMsK+O3vTSVABjdKmAW Cb1ZJAuQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fwpBf-0002pl-GK; Mon, 03 Sep 2018 13:46:39 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fwpAZ-0001jA-Li for linux-arm-kernel@lists.infradead.org; Mon, 03 Sep 2018 13:45:36 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 93AB3ED1; Mon, 3 Sep 2018 06:45:23 -0700 (PDT) Received: from localhost (e113682-lin.copenhagen.arm.com [10.32.144.41]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 298A83F557; Mon, 3 Sep 2018 06:45:22 -0700 (PDT) From: Christoffer Dall To: Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= Subject: [PULL 1/4] KVM: arm/arm64: Clean dcache to PoC when changing PTE due to CoW Date: Mon, 3 Sep 2018 15:45:13 +0200 Message-Id: <20180903134516.17796-2-christoffer.dall@arm.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180903134516.17796-1-christoffer.dall@arm.com> References: <20180903134516.17796-1-christoffer.dall@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180903_064531_912723_39288AC3 X-CRM114-Status: GOOD ( 14.61 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kvm@vger.kernel.org, Marc Zyngier , Christoffer Dall , Alexander Graf , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP From: Marc Zyngier When triggering a CoW, we unmap the RO page via an MMU notifier (invalidate_range_start), and then populate the new PTE using another one (change_pte). In the meantime, we'll have copied the old page into the new one. The problem is that the data for the new page is sitting in the cache, and should the guest have an uncached mapping to that page (or its MMU off), following accesses will bypass the cache. In a way, this is similar to what happens on a translation fault: We need to clean the page to the PoC before mapping it. So let's just do that. This fixes a KVM unit test regression observed on a HiSilicon platform, and subsequently reproduced on Seattle. Fixes: a9c0e12ebee5 ("KVM: arm/arm64: Only clean the dcache on translation fault") Reported-by: Mike Galbraith Signed-off-by: Marc Zyngier Signed-off-by: Christoffer Dall --- virt/kvm/arm/mmu.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c index 91aaf73b00df..111a660be3be 100644 --- a/virt/kvm/arm/mmu.c +++ b/virt/kvm/arm/mmu.c @@ -1860,13 +1860,20 @@ static int kvm_set_spte_handler(struct kvm *kvm, gpa_t gpa, u64 size, void *data void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte) { unsigned long end = hva + PAGE_SIZE; + kvm_pfn_t pfn = pte_pfn(pte); pte_t stage2_pte; if (!kvm->arch.pgd) return; trace_kvm_set_spte_hva(hva); - stage2_pte = pfn_pte(pte_pfn(pte), PAGE_S2); + + /* + * We've moved a page around, probably through CoW, so let's treat it + * just like a translation fault and clean the cache to the PoC. + */ + clean_dcache_guest_page(pfn, PAGE_SIZE); + stage2_pte = pfn_pte(pfn, PAGE_S2); handle_hva_to_gpa(kvm, hva, end, &kvm_set_spte_handler, &stage2_pte); }