[SeaBIOS] about ZoneHigh occupying ram from last address of below 4G ram

penghao122 at sina.com penghao122 at sina.com
Tue Apr 14 17:57:08 CEST 2015

I'm using seabios 1.7.5-0 for  kvm ,and I find some problem when using windows 7 64bit bandvirtual machine.If I configure the windows 7 64bit vm memory to 8GB ,the vm can't boot up very often(some win7-64bit version easy to trigger) .I use trace-cmd tool to trace it ,the vm just scan from last ram of below 4G(0xc000_0000) to 4G address byte by byte.This is very time-consuming.From E820 table,the address range contain nothing(it is an address hole).
I query clue from seabios because I can't find any problems in kvm or qemu.
seabios keep a range of ram from last address below 4G as  zonehigh ram .I guess  the windows os see a not aligned ram address space and scan from 0xc000_0000. so I try to change the ZoneHigh to low address space (I choose 128MB,grub use from 1MB address space).after I changed,I can boot win7-64bit vm normally.
So I want to know whether changing ZoneHigh to 128MB can be a general modification.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.seabios.org/pipermail/seabios/attachments/20150414/5295a169/attachment.html>

More information about the SeaBIOS mailing list