On 1/16/23 19:24, Nina Schoetterl-Glausch wrote:
On Thu, 2023-01-05 at 15:53 +0100, 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
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.
During RESET all CPU of the configuration are placed in
horizontal polarity.
Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
---
include/hw/s390x/cpu-topology.h | 3 +
include/hw/s390x/s390-virtio-ccw.h | 6 ++
target/s390x/cpu.h | 1 +
hw/s390x/cpu-topology.c | 92 ++++++++++++++++++++++++++++++
target/s390x/cpu-sysemu.c | 16 ++++++
target/s390x/kvm/kvm.c | 11 ++++
6 files changed, 129 insertions(+)
diff --git a/include/hw/s390x/cpu-topology.h b/include/hw/s390x/cpu-topology.h
index 9571aa70e5..33e23d78b9 100644
--- a/include/hw/s390x/cpu-topology.h
+++ b/include/hw/s390x/cpu-topology.h
@@ -55,11 +55,13 @@ typedef struct S390Topology {
QTAILQ_HEAD(, S390TopologyEntry) list;
uint8_t *sockets;
CpuTopology *smp;
+ int polarity;
} S390Topology;
#ifdef CONFIG_KVM
bool s390_has_topology(void);
void s390_topology_set_cpu(MachineState *ms, S390CPU *cpu, Error **errp);
+void s390_topology_set_polarity(int polarity);
#else
static inline bool s390_has_topology(void)
{
@@ -68,6 +70,7 @@ static inline bool s390_has_topology(void)
static inline void s390_topology_set_cpu(MachineState *ms,
S390CPU *cpu,
Error **errp) {}
+static inline void s390_topology_set_polarity(int polarity) {}
#endif
extern S390Topology s390_topology;
diff --git a/include/hw/s390x/s390-virtio-ccw.h b/include/hw/s390x/s390-virtio-ccw.h
index 9bba21a916..c1d46e78af 100644
--- a/include/hw/s390x/s390-virtio-ccw.h
+++ b/include/hw/s390x/s390-virtio-ccw.h
@@ -30,6 +30,12 @@ struct S390CcwMachineState {
uint8_t loadparm[8];
};
+#define S390_PTF_REASON_NONE (0x00 << 8)
+#define S390_PTF_REASON_DONE (0x01 << 8)
+#define S390_PTF_REASON_BUSY (0x02 << 8)
+#define S390_TOPO_FC_MASK 0xffUL
+void s390_handle_ptf(S390CPU *cpu, uint8_t r1, uintptr_t ra);
+
struct S390CcwMachineClass {
/*< private >*/
MachineClass parent_class;
diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
index 01ade07009..5da4041576 100644
--- a/target/s390x/cpu.h
+++ b/target/s390x/cpu.h
@@ -864,6 +864,7 @@ void s390_do_cpu_set_diag318(CPUState *cs, run_on_cpu_data arg);
int s390_assign_subch_ioeventfd(EventNotifier *notifier, uint32_t sch_id,
int vq, bool assign);
void s390_cpu_topology_reset(void);
+void s390_cpu_topology_set(void);
I don't like this name much, it's nondescript.
s390_cpu_topology_set_modified ?
yes, better.
#ifndef CONFIG_USER_ONLY
unsigned int s390_cpu_set_state(uint8_t cpu_state, S390CPU *cpu);
#else
diff --git a/hw/s390x/cpu-topology.c b/hw/s390x/cpu-topology.c
index 438055c612..e6b4692581 100644
--- a/hw/s390x/cpu-topology.c
+++ b/hw/s390x/cpu-topology.c
@@ -97,6 +97,98 @@ static s390_topology_id s390_topology_from_cpu(S390CPU *cpu)
}
/**
+ * s390_topology_set_polarity
+ * @polarity: horizontal or vertical
+ *
+ * Changes the polarity of all the CPU in the configuration.
+ *
+ * If the dedicated CPU modifier attribute is set a vertical
+ * polarization is always high (Architecture).
+ * Otherwise we decide to set it as medium.
+ *
+ * Once done, advertise a topology change.
+ */
+void s390_topology_set_polarity(int polarity)
I don't like that this function ignores what kind of vertical polarization is passed,
it's confusing.
That seems like a further reason to split horizontal/vertical from the entitlement.
OK, you are right.
I remove this function and put the s390_cpu_topology_set() inside the
handle_ptf()
+{
+ S390TopologyEntry *entry;
I also expected this function to set s390_topology.polarization, but it doesn't.
+
+ QTAILQ_FOREACH(entry, &s390_topology.list, next) {
+ if (polarity == S390_TOPOLOGY_POLARITY_HORIZONTAL) {
+ entry->id.p = polarity;
+ } else {
+ if (entry->id.d) {
+ entry->id.p = S390_TOPOLOGY_POLARITY_VERTICAL_HIGH;
+ } else {
+ entry->id.p = S390_TOPOLOGY_POLARITY_VERTICAL_MEDIUM;
+ }
+ }
+ }
+ s390_cpu_topology_set();
+}
+
+/*
+ * s390_handle_ptf:
+ *
+ * @register 1: contains the function code
+ *
+ * Function codes 0 and 1 handle the CPU polarization.
+ * We assume an horizontal topology, the only one supported currently
+ * by Linux, consequently we answer to function code 0, requesting
+ * horizontal polarization that it is already the current polarization
+ * and reject vertical polarization request without further explanation.
This comment is outdated, right? Same for those in the function body.
+ *
+ * Function code 2 is handling topology changes and is interpreted
+ * by the SIE.
+ */
+void s390_handle_ptf(S390CPU *cpu, uint8_t r1, uintptr_t ra)
+{
+ CPUS390XState *env = &cpu->env;
+ uint64_t reg = env->regs[r1];
+ uint8_t fc = reg & S390_TOPO_FC_MASK;
+
+ if (!s390_has_feat(S390_FEAT_CONFIGURATION_TOPOLOGY)) {
+ s390_program_interrupt(env, PGM_OPERATION, ra);
+ return;
+ }
+
+ if (env->psw.mask & PSW_MASK_PSTATE) {
+ s390_program_interrupt(env, PGM_PRIVILEGED, ra);
+ return;
+ }
+
+ if (reg & ~S390_TOPO_FC_MASK) {
+ s390_program_interrupt(env, PGM_SPECIFICATION, ra);
+ return;
+ }
+
+ switch (fc) {
+ case 0: /* Horizontal polarization is already set */
+ if (s390_topology.polarity == S390_TOPOLOGY_POLARITY_HORIZONTAL) {
+ env->regs[r1] |= S390_PTF_REASON_DONE;
+ setcc(cpu, 2);
+ } else {
+ s390_topology_set_polarity(S390_TOPOLOGY_POLARITY_HORIZONTAL);
+ s390_topology.polarity = S390_TOPOLOGY_POLARITY_HORIZONTAL;
+ setcc(cpu, 0);
+ }
+ break;
+ case 1: /* Vertical polarization is not supported */
+ if (s390_topology.polarity != S390_TOPOLOGY_POLARITY_HORIZONTAL) {
+ env->regs[r1] |= S390_PTF_REASON_DONE;
+ setcc(cpu, 2);
+ } else {
+ s390_topology_set_polarity(S390_TOPOLOGY_POLARITY_VERTICAL_LOW);
This is why I said it's confusing, nothing gets set to LOW.
+ s390_topology.polarity = S390_TOPOLOGY_POLARITY_VERTICAL_LOW;
Why LOW here?
I wanted something not being S390_TOPOLOGY_POLARITY_HORIZONTAL and did
not want to define a S390_TOPOLOGY_POLARITY_VERTICAL.
OK I define S390_TOPOLOGY_POLARITY_HORIZONTAL=0 and ..._VERTICAL=1
+ setcc(cpu, 0);
+ }
+ break;
+ default:
+ /* Note that fc == 2 is interpreted by the SIE */
+ s390_program_interrupt(env, PGM_SPECIFICATION, ra);
+ }
You can simplify this by doing:
int new_polarity;
switch (fc) {
case 0:
new_polarity = S390_TOPOLOGY_POLARITY_HORIZONTAL;
break;
case 1:
new_polarity = S390_TOPOLOGY_POLARITY_VERTICAL_?;
break;
default:
/* Note that fc == 2 is interpreted by the SIE */
s390_program_interrupt(env, PGM_SPECIFICATION, ra);
return;
}
if same polarity:
rc done, rejected
else
set polarity, initiated
Might be a good idea to turn the polarity values into an enum.
+}
[...]
Even I never really understood the added value of an enum I can do this.
Thanks,
regards,
Pierre
--
Pierre Morel
IBM Lab Boeblingen
