On Di, 2016-05-17 at 14:44 -0600, Alex Williamson wrote:
QEMU provides two fw_cfg files to support IGD. The first holds the OpRegion data which holds the Video BIOS Table (VBT). This needs to be copied into reserved memory and the address stored in the ASL Storage register of the device at 0xFC offset in PCI config space. The OpRegion is generally 8KB. This file is named "etc/igd-opregion".
The second file tells us the required size of the stolen memory space for the device. This space requires 1MB alignment and is generally either 1MB to 8MB depending on hardware config, but may be hundreds of MB for user specified stolen memory. The base address of the reserved memory allocated for this is written back to the Base Data of Stolen Memory register (BDSM) at PCI config offset 0x5C on the device. This file is named "etc/igd-bdsm-size".
QEMU documents these fw_cfg entries in docs/igd-assign.txt.
Signed-off-by: Alex Williamson alex.williamson@redhat.com
v6: fw_cfg BDSM entry now holds an 8-byte size integer as suggested by Gerd. Also renamed to etc/igd-bdsm-size. Filter based on bdf to only make use of this for the Intel VGA device at address 00:02.0, not that QEMU should attach this to anything else.
As always, comments appreciated. I expect this will be on hold pending the QEMU support:
http://thread.gmane.org/gmane.comp.emulators.kvm.devel/152123
qemu patches are merged meanwhile.
Patch applied to master and cherry-picked into 1.9-stable.
thanks, Gerd