On Thu, Jun 20, 2024 at 04:57:35PM GMT, John Levon wrote:
On Thu, Jun 20, 2024 at 05:47:25PM +0200, Igor Mammedov wrote:
well you just upgraded 'hardware' for legacy OS, there is no guaranties that it will continue to work without any changes.
Are you saying that seabios doesn't attempt to provide a stable virtual hardware platform at all? Is that written down somewhere?
Well, seabios behavior did change in the past and probably will continue to change to make modern workloads work better.
We try to not break existing stuff, this is why the heuristic is there in the first place. The idea is: If there is no memory above 4G it is more likely that the OS in the VM does not support long mode or PAE paging mode, so better don't place pci bars above 4G.
Obviously it is not always working out as planned ...
It is certainly unfortunate that is took us so long to rediscover this (sorry), but again - the Linux policy is *very* clear on this - you don't get to introduce a regression for something that worked previously in order to support something new that didn't previously work.
Well. You are comparing apples with oranges here. Linux has a much easier job, it can simply add new interfaces (typically syscalls) for new stuff. seabios is stuck with software interfaces which are fixed and for the most part have been defined in the last century ...
take care, Gerd