xen: allow enable use of VGA console on dom0

Get the information about the VGA console hardware from Xen, and put
it into the form the bootloader normally generates, so that the rest
of the kernel can deal with VGA as usual.

[ Impact: make VGA console work in dom0 ]

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
[v1: Rebased on 2.6.39]
[v2: Removed incorrect comments and fixed compile warnings]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index e3c6a06cf725..4abd2d5d04f7 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1241,6 +1241,14 @@ asmlinkage void __init xen_start_kernel(void)
                 if (pci_xen)
                         x86_init.pci.arch_init = pci_xen_init;
         } else {
+                const struct dom0_vga_console_info *info =
+                        (void *)((char *)xen_start_info +
+                                 xen_start_info->console.dom0.info_off);
+
+                xen_init_vga(info, xen_start_info->console.dom0.info_size);
+                xen_start_info->console.domU.mfn = 0;
+                xen_start_info->console.domU.evtchn = 0;
+
                 /* Make sure ACS will be enabled */
                 pci_request_acs();
         }