| |
| 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 |
| ``-device secondary-vga`` |
| legacy-free pci 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+). |
| |
| |
| The legacy-free variant has no ROM and has ``PCI_CLASS_DISPLAY_OTHER`` |
| instead of ``PCI_CLASS_DISPLAY_VGA``. |
| |
| |
| IO ports used |
| ------------- |
| |
| Doesn't apply to the legacy-free pci variant, use the MMIO bar instead. |
| |
| ``03c0 - 03df`` |
| standard vga ports |
| ``01ce`` |
| bochs vbe interface index port |
| ``01cf`` |
| bochs vbe interface data port (x86 only) |
| ``01d0`` |
| 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`` |
| edid data blob. |
| ``0400 - 041f`` |
| vga ioports (``0x3c0`` to ``0x3df``), remapped 1:1. Word access |
| is supported, bytes are written in little endian 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. |
| ``0600 - 0607`` |
| QEMU extended registers. QEMU 2.2+ only. |
| The pci revision is 2 (or greater) when these registers are present. |
| The registers are 32bit. |
| ``0600`` |
| QEMU extended register region size, in bytes. |
| ``0604`` |
| framebuffer endianness register. |
| - ``0xbebebebe`` indicates big endian. |
| - ``0x1e1e1e1e`` indicates little endian. |
