On Tue, Mar 24, 2020 at 7:48 PM Theodore Y. Ts'o [off-list ref] wrote:

On Tue, Mar 24, 2020 at 09:29:58AM +0000, Peter Maydell wrote:

quoted

On the contrary, that would be a much better interface for QEMU.
We always know when we're doing an open-syscall on behalf
of the guest, and it would be trivial to make the fcntl() call then.
That would ensure that we don't accidentally get the
'32-bit semantics' on file descriptors QEMU opens for its own
purposes, and wouldn't leave us open to the risk in future that
setting the PER_LINUX32 flag for all of QEMU causes
unexpected extra behaviour in future kernels that would be correct
for the guest binary but wrong/broken for QEMU's own internals.

If using a flag set by fcntl is better for qemu, then by all means
let's go with that instead of using a personality flag/number.

Linus, do you have what you need to do a respin of the patch?

Absolutely, I'm a bit occupied this week but I will try to get to it
early next week!

Thanks a lot for the directions here, it's highly valuable.

Yours,
Linus Walleij