From cc22824860a18e9e073496396b1cfc860d010a26 Mon Sep 17 00:00:00 2001 From: Gerd Hoffmann Date: Mon, 15 Oct 2012 08:02:56 +0200 Subject: [PATCH] vga: add specs for standard vga Signed-off-by: Gerd Hoffmann Signed-off-by: Blue Swirl --- docs/specs/standard-vga.txt | 64 +++++++++++++++++++++++++++++++++++++++++++++ hw/vga-isa.c | 2 ++ hw/vga-pci.c | 2 ++ 3 files changed, 68 insertions(+) create mode 100644 docs/specs/standard-vga.txt diff --git a/docs/specs/standard-vga.txt b/docs/specs/standard-vga.txt new file mode 100644 index 0000000000..1cecccd469 --- /dev/null +++ b/docs/specs/standard-vga.txt @@ -0,0 +1,64 @@ + +QEMU Standard VGA +================= + +Exists in two variants, for isa and pci. + +command line switches: + -vga std [ picks isa for -M isapc, otherwise pci ] + -device VGA [ pci variant ] + -device isa-vga [ isa variant ] + + +PCI spec +-------- + +Applies to the pci variant only for obvious reasons. + +PCI ID: 1234:1111 + +PCI Region 0: + Framebuffer memory, 16 MB in size (by default). + Size is tunable via vga_mem_mb property. + +PCI Region 1: + Reserved (so we have the option to make the framebuffer bar 64bit). + +PCI Region 2: + MMIO bar, 4096 bytes in size (qemu 1.3+) + +PCI ROM Region: + Holds the vgabios (qemu 0.14+). + + +IO ports used +------------- + +03c0 - 03df : standard vga ports +01ce : bochs vbe interface index port +01cf : bochs vbe interface data port + + +Memory regions used +------------------- + +0xe0000000 : Framebuffer memory, isa variant only. + +The pci variant used to mirror the framebuffer bar here, qemu 0.14+ +stops doing that (except when in -M pc-$old compat mode). + + +MMIO area spec +-------------- + +Likewise applies to the pci variant only for obvious reasons. + +0000 - 03ff : reserved, for possible virtio extension. +0400 - 041f : vga ioports (0x3c0 -> 0x3df), remapped 1:1. + word access is supported, bytes are written + in little endia order (aka index port first), + so indexed registers can be updated with a + single mmio write (and thus only one vmexit). +0500 - 0515 : bochs dispi interface registers, mapped flat + without index/data ports. Use (index << 1) + as offset for (16bit) register access. diff --git a/hw/vga-isa.c b/hw/vga-isa.c index d2904737bc..046602b3d2 100644 --- a/hw/vga-isa.c +++ b/hw/vga-isa.c @@ -1,6 +1,8 @@ /* * QEMU ISA VGA Emulator. * + * see docs/specs/standard-vga.txt for virtual hardware specs. + * * Copyright (c) 2003 Fabrice Bellard * * Permission is hereby granted, free of charge, to any person obtaining a copy diff --git a/hw/vga-pci.c b/hw/vga-pci.c index f7d0256e87..5c4daee397 100644 --- a/hw/vga-pci.c +++ b/hw/vga-pci.c @@ -1,6 +1,8 @@ /* * QEMU PCI VGA Emulator. * + * see docs/specs/standard-vga.txt for virtual hardware specs. + * * Copyright (c) 2003 Fabrice Bellard * * Permission is hereby granted, free of charge, to any person obtaining a copy -- 2.11.0