From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin O'Connor Subject: Re: [RFC PATCH v4] fw/pci: Add support for mapping Intel IGD via QEMU Date: Tue, 23 Feb 2016 10:22:33 -0500 Message-ID: <20160223152233.GB17600@morn.lan> References: <20160216213540.14607.97134.stgit@gimli.home> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: seabios@seabios.org, allen.m.kay@intel.com, qemu-devel@nongnu.org, kvm@vger.kernel.org To: Alex Williamson Return-path: Received: from mail-qg0-f42.google.com ([209.85.192.42]:34072 "EHLO mail-qg0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753618AbcBWPWg (ORCPT ); Tue, 23 Feb 2016 10:22:36 -0500 Received: by mail-qg0-f42.google.com with SMTP id b67so138662125qgb.1 for ; Tue, 23 Feb 2016 07:22:35 -0800 (PST) Content-Disposition: inline In-Reply-To: <20160216213540.14607.97134.stgit@gimli.home> Sender: kvm-owner@vger.kernel.org List-ID: On Tue, Feb 16, 2016 at 02:39:27PM -0700, Alex Williamson wrote: > QEMU provides two fw_cfg files to support IGD. The first holds the > OpRegion data which holds the Video BIOS Table (VBT). This needs to > be copied into reserved memory and the address stored in the ASL > Storage register of the device at 0xFC offset in PCI config space. > The OpRegion is generally 8KB. This file is named "etc/igd-opregion". > > The second file tells us the required size of the stolen memory space > for the device. This is a dummy file, it has no backing so we only > allocate the space without copying anything into it. This space > requires 1MB alignment and is generally either 1MB or 2MB, depending > on the hardware config. If the user has opted in QEMU to expose > additional stolen memory beyond the GTT (GGMS), the GMS may add an > additional 32MB to 512MB. The base address of the reserved memory > allocated for this is written back to the Base Data of Stolen Memory > register (BDSM) at PCI config offset 0x5C on the device. This file is > named "etc/igd-bdsm". Thanks. I'd be interested in seeing how the discussion with Michael and Igor works out (wrt using a standardized interface for communicating addresses between qemu and firmware) before adopting this interface in SeaBIOS. -Kevin