On 01/02/2023 14.20, Pierre Morel wrote:
When the host supports the CPU topology facility, the PTF
instruction with function code 2 is interpreted by the SIE,
provided that the userland hypervizor activates the interpretation
s/hypervizor/hypervisor/
by using the KVM_CAP_S390_CPU_TOPOLOGY KVM extension.
The PTF instructions with function code 0 and 1 are intercepted
and must be emulated by the userland hypervizor.
dito
During RESET all CPU of the configuration are placed in
horizontal polarity.
Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
---
...
/**
* s390_topology_reset:
*
* Generic reset for CPU topology, calls s390_topology_reset()
* s390_topology_reset() to reset the kernel Modified Topology
* change record.
+ * Then set global and all CPUs polarity to POLARITY_HORIZONTAL.
You describe here already what's going to happen...
*/
void s390_topology_reset(void)
{
s390_cpu_topology_reset();
+ /* Set global polarity to POLARITY_HORIZONTAL */
... then here again ...
+ s390_topology.polarity = POLARITY_HORIZONTAL;
... and the code is (fortunately) also very self-exaplaining...
+ /* Set all CPU polarity to POLARITY_HORIZONTAL */
+ s390_topology_set_cpus_polarity(POLARITY_HORIZONTAL);
... so I'd rather drop the two comments within the function body.
}
(rest of the patch looks fine to me)
Thomas
