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Re: [PATCH v15 06/11] s390x/cpu topology: interception of PTF instructio
From: |
Thomas Huth |
Subject: |
Re: [PATCH v15 06/11] s390x/cpu topology: interception of PTF instruction |
Date: |
Mon, 6 Feb 2023 12:38:08 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.13.0 |
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@linux.ibm.com>
---
...
/**
* 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
[PATCH v15 07/11] target/s390x/cpu topology: activating CPU topology, Pierre Morel, 2023/02/01
[PATCH v15 06/11] s390x/cpu topology: interception of PTF instruction, Pierre Morel, 2023/02/01
[PATCH v15 09/11] machine: adding s390 topology to query-cpu-fast, Pierre Morel, 2023/02/01