On Wed, Jun 12, 2024 at 03:30:18PM +0200, Gerd Hoffmann wrote:
I see that no change has been made to seabios for this regression. Is it the position of the maintainers that such guest VMs are no longer supported by seabios, and anyone doing so is responsible for patching as necessary? Or would there still be interest in fixing this up in master?
So, in short, can you (or anyone else running into this) share some information what the typical / maximal amount of memory is for 32-bit guests in real world deployments?
I asked internally for some production details - it's partial information, but still indicative. The sizable majority of deployments are indeed at 4G or below. However there is in fact a non-trivial minority with 4G-64G configured, and even a few over 64G! Presumably nobody ever noticed the latter cases weren't actually using that memory.
So from a "will this change stop my production VM from booting" perspective, there's no magic number here, though 64G certainly seems like a very reasonable cutoff point - beyond having to fix up the VM config, there's no possible way that could affect any actual workload in practice.
Although this actually works at 63G, right, due to the memory layout?
I have a patch series that implements the above if you're interested...
regards john