From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?ISO-8859-1?Q?Roger_Pau_Monn=E9?= Subject: Re: [PATCH v3 4/4] xen: expose that grant table mappings update the IOMMU Date: Mon, 26 May 2014 18:10:19 +0200 Message-ID: <5383676B.2060405@citrix.com> References: <1400862788-22037-1-git-send-email-roger.pau@citrix.com> <1400862788-22037-5-git-send-email-roger.pau@citrix.com> <53832A620200007800015A96@mail.emea.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta14.messagelabs.com ([193.109.254.103]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1WoxTk-0004qt-UY for xen-devel@lists.xenproject.org; Mon, 26 May 2014 16:10:25 +0000 In-Reply-To: <53832A620200007800015A96@mail.emea.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich Cc: xen-devel@lists.xenproject.org, Keir Fraser List-Id: xen-devel@lists.xenproject.org On 26/05/14 11:49, Jan Beulich wrote: >>>> On 23.05.14 at 18:33, wrote: >> Add a new XENFEAT_hvm_gntmap_supports_iommu that is used to check >> whether the hypervisor properly updates the IOMMU on auto-translated >> guests when doing a grant table map/unmap operation. > > As said before, if this is indeed HVM-only (I assume PVH is being > implied here), this should be exposed via the new CPUID leaf > rather than via the feature map. OK, I've been looking into this, but it seems that for PVH cpuid is limited to 2 leafs only, so hvm_hypervisor_cpuid_leaf is never called. Will look into expanding this, but then I should probably add some checks to prevent PVH guests from reporting either XEN_HVM_CPUID_APIC_ACCESS_VIRT or XEN_HVM_CPUID_X2APIC_VIRT for the time being. Roger.