Oliver Upton <[email protected]> writes:
On Mon, May 04, 2026 at 09:18:01PM +0000, Colton Lewis wrote:
We may want a partitioned PMU but not have FEAT_FGT to untrap the
specific registers that would normally be untrapped. Add handling for
those trapped register accesses that does the right thing if the PMU
is partitioned.
For registers that shouldn't be written to hardware because they
require special handling (PMEVTYPER and PMOVS), write to the virtual
register. A later patch will ensure these are handled correctly at
vcpu_load time.
Signed-off-by: Colton Lewis <[email protected]>
I'd prefer an approach that provides a single accessor helper that takes
a vcpu_sysreg enum as an argument and internally handles the dispatch
between partitioned and emulated PMUs. That goes for all of the PMU
sysregs.
That seems ugly to me. It'll need a giant switch or two to re-dispatch
to the correct sysreg handling when we were already dispatched courtesy
of the function we are in.
Are you thinking:
single_accessor(vcpu_sysreg)
{
if (is_partitioned) {
switch (vcpu_sysreg) {
...
}
return;
}
switch (vcpu_sysreg) {
...
}
}
or I could do the switch on the outside and duplicate the is_partitioned
check but that's the same as what happens now with extra steps.
This will help you reuse some of the PMU emuation code that you'll still
need for things like nested...
I'm not seeing what you mean. Could you explain further please?
Thanks,
Oliver
