From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laszlo Ersek Subject: Re: xen EFI boot and vga-passthrough Date: Mon, 12 Nov 2012 22:24:22 +0100 Message-ID: <50A16906.9000301@redhat.com> References: <19EF9FEB5AF86243A3F18E5CE75971640A00B0F5@hagsted-bserver.hagsted.dk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <19EF9FEB5AF86243A3F18E5CE75971640A00B0F5@hagsted-bserver.hagsted.dk> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Kristian Hagsted Rasmussen Cc: "xen-devel@lists.xen.org" List-Id: xen-devel@lists.xenproject.org On 11/12/12 20:08, Kristian Hagsted Rasmussen wrote: > Hi all > > I can't seem to find any information on vga-passthrough when booting > through xen.efi, so I assume it should work. But I encounter a problem > on a windows 7 HVM that boots fine when dom0 is booted through MBR but > fails when dom0 is booted through UEFI. > > My system is: > DQ77KB motherboard with bios version 44 > Core i7-3779T with VT-d > Intel HD graphics 4000 > > In the qemu log it seem like xen cannot reach the vga-bios. Is this a > known problem when booting through xen.efi or is it a bug? The legacy VGA BIOS is not present on UEFI platforms unless an (optional) compatibility support module provides it. (Tangentially, Secure Boot disables CSMs.) Windows 7 / Windows 2008 R2 have a bug: even when booted on an UEFI platform, they depend on the optional VGA BIOS unconditionally. This seems to have been fixed in Windows 8 / Windows Server 2012. See and/or the long "OVMF + Windows 2008 r2 sp1" thread on edk2-devel. (Apologies if I misunderstood your question. Admittedly, I haven't done any homework wrt. xen.efi or vga passthrough. But your email had too many keywords to push my buttons.) Laszlo