standard-vga.txt (2309B)
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.