From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: qemu/hw/device-assignment: questions about msix_table_page Date: Mon, 27 Apr 2009 16:13:05 +0300 Message-ID: <20090427131305.GA2272@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Avi Kivity , Marcelo Tosatti , kvm@vger.kernel.org To: Sheng Yang Return-path: Received: from mx2.redhat.com ([66.187.237.31]:60373 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755124AbZD0NOI (ORCPT ); Mon, 27 Apr 2009 09:14:08 -0400 Content-Disposition: inline Sender: kvm-owner@vger.kernel.org List-ID: Sheng, Marcelo, I've been reading code in qemu/hw/device-assignment.c, and I have a couple of questions about msi-x implementation: 1. What is the reason that msix_table_page is allocated with mmap and not with e.g. malloc? 2. msix_table_page has the guest view of the msix table for the device. However, even this memory isn't mapped into guest directly, instead msix_mmio_read/msix_mmio_write perform the write in qemu. Won't it be possible to map this page directly into guest memory, reducing the overhead for table writes? Could you shed light on this for me please? Thanks, ( ------) ( Resending with a sane subject/reply-to address. ) ( Sorry about multiple copies.) -- MST