From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 1/3] KVM: Emulation MSI-X mask bits for assigned devices Date: Wed, 29 Sep 2010 10:36:25 +0200 Message-ID: <4CA2FA89.3010809@redhat.com> References: <1285667052-24907-1-git-send-email-sheng@linux.intel.com> <1285667052-24907-2-git-send-email-sheng@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , kvm@vger.kernel.org To: Sheng Yang Return-path: Received: from mx1.redhat.com ([209.132.183.28]:63767 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754205Ab0I2Igb (ORCPT ); Wed, 29 Sep 2010 04:36:31 -0400 In-Reply-To: <1285667052-24907-2-git-send-email-sheng@linux.intel.com> Sender: kvm-owner@vger.kernel.org List-ID: On 09/28/2010 11:44 AM, Sheng Yang wrote: > This patch enable per-vector mask for assigned devices using MSI-X. > > + > struct kvm_assigned_msix_entry { > __u32 assigned_dev_id; > __u32 gsi; > __u16 entry; /* The index of entry in the MSI-X table */ > - __u16 padding[3]; > + __u16 flags; > + __u16 padding[2]; > }; > Given that this field wasn't a flag field previously, we can't expect it to be zero. So before we can check it, userspace needs to tell us that is knows the field is not padding, but a flags field. You can use KVM_ENABLE_CAP for that. -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.