Am 19.01.22 um 12:52 schrieb Thomas Huth:
On 18/01/2022 10.52, Janis Schoetterl-Glausch wrote:
Channel I/O honors storage keys and is performed on absolute memory.
For I/O emulation user space therefore needs to be able to do key
checked accesses.
Can't we do the checking in userspace? We already have functions for handling the storage keys there (see hw/s390x/s390-skeys-kvm.c), so why can't we do the checking in QEMU?
That would separate the key check from the memory operation. Potentially for a long time.
Wenn we piggy back on access_guest_abs_with_key we use mvcos in the host and thus do the key check in lockstep with the keycheck which is the preferrable solution.
I would also like to avoid reading guest storage keys via the ioctl that was done for migration in the I/O path just to do a single key check. This has peformance concerns.
