From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoffer Dall Subject: Re: [PATCH v3 2/3] arm/arm64: KVM: Invalidate data cache on unmap Date: Thu, 29 Jan 2015 15:02:58 +0100 Message-ID: <20150129140258.GH9055@cbox> References: <1421865588-19761-1-git-send-email-marc.zyngier@arm.com> <1421865588-19761-3-git-send-email-marc.zyngier@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, Peter Maydell , Steve Capper To: Marc Zyngier Return-path: Received: from mail-lb0-f181.google.com ([209.85.217.181]:54337 "EHLO mail-lb0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752205AbbA2OCs (ORCPT ); Thu, 29 Jan 2015 09:02:48 -0500 Received: by mail-lb0-f181.google.com with SMTP id u10so28331005lbd.12 for ; Thu, 29 Jan 2015 06:02:46 -0800 (PST) Content-Disposition: inline In-Reply-To: <1421865588-19761-3-git-send-email-marc.zyngier@arm.com> Sender: kvm-owner@vger.kernel.org List-ID: On Wed, Jan 21, 2015 at 06:39:47PM +0000, Marc Zyngier wrote: > Let's assume a guest has created an uncached mapping, and written > to that page. Let's also assume that the host uses a cache-coherent > IO subsystem. Let's finally assume that the host is under memory > pressure and starts to swap things out. > > Before this "uncached" page is evicted, we need to make sure > we invalidate potential speculated, clean cache lines that are > sitting there, or the IO subsystem is going to swap out the > cached view, loosing the data that has been written directly > into memory. > > Signed-off-by: Marc Zyngier Reviewed-by: Christoffer Dall