Re: [PATCH net-next 06/10] net/mlx4_core: Fix struct mlx4_vhcr_cmd to make implicit padding explicit

Jack Morgenstein
2015-01-27T14:42:02Z

On Tue, 27 Jan 2015 13:38:28 +0000
David Laight <David.Laight@ACULAB.COM> wrote:

> Haven't you broken communication between an old and new
> 32bit Guests and 32bit hosts (assuming they exist)?

Yes, but I don't see any interest on the net in running 32-bit Hosts
with virtualization and SR IOV. I do see that there is interest in
running 32-bit Guests over 64-bit Hosts (which configuration KVM
supports).

Since this change is *required* for supporting 32-bit Guests on 64-bit
Hosts, I don't see that we have much choice here.

As you say, an old 32-bit Host will not be compatible with a new 32-bit
guest, and vice-versa. However, I would assume that almost all Hosts
would have 64-bit architectures, because of the performance and
memory-space requirements for running SRIOV and virtualization.
Therefore, I don't see this as a stopper.

-Jack