]> git.proxmox.com Git - mirror_qemu.git/blob - docs/specs/standard-vga.txt
migration/savevm: wrap into qemu_loadvm_state_header()
[mirror_qemu.git] / docs / specs / standard-vga.txt
1
2 QEMU Standard VGA
3 =================
4
5 Exists in two variants, for isa and pci.
6
7 command line switches:
8 -vga std [ picks isa for -M isapc, otherwise pci ]
9 -device VGA [ pci variant ]
10 -device isa-vga [ isa variant ]
11 -device secondary-vga [ legacy-free pci variant ]
12
13
14 PCI spec
15 --------
16
17 Applies to the pci variant only for obvious reasons.
18
19 PCI ID: 1234:1111
20
21 PCI Region 0:
22 Framebuffer memory, 16 MB in size (by default).
23 Size is tunable via vga_mem_mb property.
24
25 PCI Region 1:
26 Reserved (so we have the option to make the framebuffer bar 64bit).
27
28 PCI Region 2:
29 MMIO bar, 4096 bytes in size (qemu 1.3+)
30
31 PCI ROM Region:
32 Holds the vgabios (qemu 0.14+).
33
34
35 The legacy-free variant has no ROM and has PCI_CLASS_DISPLAY_OTHER
36 instead of PCI_CLASS_DISPLAY_VGA.
37
38
39 IO ports used
40 -------------
41
42 Doesn't apply to the legacy-free pci variant, use the MMIO bar instead.
43
44 03c0 - 03df : standard vga ports
45 01ce : bochs vbe interface index port
46 01cf : bochs vbe interface data port (x86 only)
47 01d0 : bochs vbe interface data port
48
49
50 Memory regions used
51 -------------------
52
53 0xe0000000 : Framebuffer memory, isa variant only.
54
55 The pci variant used to mirror the framebuffer bar here, qemu 0.14+
56 stops doing that (except when in -M pc-$old compat mode).
57
58
59 MMIO area spec
60 --------------
61
62 Likewise applies to the pci variant only for obvious reasons.
63
64 0000 - 03ff : edid data blob.
65 0400 - 041f : vga ioports (0x3c0 -> 0x3df), remapped 1:1.
66 word access is supported, bytes are written
67 in little endia order (aka index port first),
68 so indexed registers can be updated with a
69 single mmio write (and thus only one vmexit).
70 0500 - 0515 : bochs dispi interface registers, mapped flat
71 without index/data ports. Use (index << 1)
72 as offset for (16bit) register access.
73
74 0600 - 0607 : qemu extended registers. qemu 2.2+ only.
75 The pci revision is 2 (or greater) when
76 these registers are present. The registers
77 are 32bit.
78 0600 : qemu extended register region size, in bytes.
79 0604 : framebuffer endianness register.
80 - 0xbebebebe indicates big endian.
81 - 0x1e1e1e1e indicates little endian.