From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH 6/6] KVM: assigned dev: MSI-X mask support Date: Thu, 18 Nov 2010 08:21:40 +0200 Message-ID: <20101118062140.GB8731@redhat.com> References: <1289812532-3227-1-git-send-email-sheng@linux.intel.com> <1289812532-3227-7-git-send-email-sheng@linux.intel.com> <4CE3DF68.7090309@redhat.com> <201011180958.55773.sheng@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Avi Kivity , Marcelo Tosatti , kvm@vger.kernel.org, Alex Williamson To: Sheng Yang Return-path: Received: from mx1.redhat.com ([209.132.183.28]:8315 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754734Ab0KRGVv (ORCPT ); Thu, 18 Nov 2010 01:21:51 -0500 Content-Disposition: inline In-Reply-To: <201011180958.55773.sheng@linux.intel.com> Sender: kvm-owner@vger.kernel.org List-ID: On Thu, Nov 18, 2010 at 09:58:55AM +0800, Sheng Yang wrote: > > > +static int msix_mmio_write(struct kvm_io_device *this, gpa_t addr, int > > > len, + const void *val) > > > +{ > > > + struct kvm_assigned_dev_kernel *adev = > > > + container_of(this, struct kvm_assigned_dev_kernel, > > > + msix_mmio_dev); > > > + int idx, r = 0; > > > + unsigned long new_val = *(unsigned long *)val; > > > > What if it's a 64-bit write on a 32-bit host? > > In fact we haven't support QWORD(64bit) accessing now. The reason is we haven't > seen any OS is using it in this way now, so I think we can leave it later. > > Also seems QEmu doesn't got the way to handle 64bit MMIO. I think it does. I think it simply splits these to 32-bit transactions and handles as such. That seems to be spec-compilant. I wouldn't want us to regress. -- MST