From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH v5] KVM: VMX: Execute WBINVD to keep data consistency with assigned devices Date: Tue, 29 Jun 2010 13:44:25 +0300 Message-ID: <4C29CE89.6010206@redhat.com> References: <4C286CCE.10309@redhat.com> <1277781419-13227-1-git-send-email-sheng@linux.intel.com> <20100629101403.GB1788@amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Sheng Yang , Marcelo Tosatti , Jan Kiszka , "kvm@vger.kernel.org" , "Yaozu (Eddie) Dong" To: "Roedel, Joerg" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:37114 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755142Ab0F2Koc (ORCPT ); Tue, 29 Jun 2010 06:44:32 -0400 In-Reply-To: <20100629101403.GB1788@amd.com> Sender: kvm-owner@vger.kernel.org List-ID: On 06/29/2010 01:14 PM, Roedel, Joerg wrote: > On Mon, Jun 28, 2010 at 11:16:59PM -0400, Sheng Yang wrote: > >> Some guest device driver may leverage the "Non-Snoop" I/O, and explicitly >> WBINVD or CLFLUSH to a RAM space. Since migration may occur before WBINVD or >> CLFLUSH, we need to maintain data consistency either by: >> 1: flushing cache (wbinvd) when the guest is scheduled out if there is no >> wbinvd exit, or >> 2: execute wbinvd on all dirty physical CPUs when guest wbinvd exits. >> > Sorry for jumping in late. This code is not required on AMD platforms > because the io-page-tables for the AMD IOMMU have a FC bit (force > coherent) that must just be set. The current code does not set this bit > but I will prepare a patch for that. This wbinvd emulation code should > be avoided where possible. > Do you mean, KVM_IOMMU_CACHE_COHERENCY should be set for the AMD IOMMU? -- error compiling committee.c: too many arguments to function