On 8/4/22 00:17, Thomas Huth wrote:
On 03/08/2022 15.58, Nico Boehr wrote:
QEMU doesn't provide EQBS/SQBS instructions, so we should check they
result in an exception.
I somewhat fail to see the exact purpose of this patch... QEMU still doesn't
emulate a lot of other instructions, too, so why are we checking now these
QBS instructions? Why not all the others? Why do we need a test to verify
that there is an exception in this case - was there a bug somewhere that
didn't cause an exception in certain circumstances?
Looking at the patch that introduced the QEMU handlers (1eecf41b) I
wonder why those two cases were added. From my point of view it makes
sense to remove the special handling for those two instructions.
@Christian: Any idea why this was added? Can we remove it?
The only reason I can think of to test this is the existence of EC* bits
that control the behavior for those instructions. So if we set those
without having QEMU handling code then we're in trouble.
But then I'd also expect that we need to set a stfle bit to indicate the
availability and this test doesn't check for that and would indicate a
false-positive.
