For historical reasons, we compute CPU device-tree ids with a non-trivial
logic. This patch consolidate the logic in a single helper to be used
in various places where it is currently open-coded.
It is okay to get rid of DIV_ROUND_UP() because we're sure that the number
of threads per core in the guest cannot exceed the number of threads per
core in the host.
Signed-off-by: Greg Kurz <gr...@kaod.org>
---
hw/ppc/spapr.c | 6 ++----
target/ppc/cpu.h | 17 +++++++++++++++++
target/ppc/translate_init.c | 3 +--
3 files changed, 20 insertions(+), 6 deletions(-)
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 75e298b4c6be..1bb05a9a6b07 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -981,7 +981,6 @@ static void *spapr_build_fdt(sPAPRMachineState *spapr,
void *fdt;
sPAPRPHBState *phb;
char *buf;
- int smt = kvmppc_smt_threads();
fdt = g_malloc0(FDT_MAX_SIZE);
_FDT((fdt_create_empty_tree(fdt, FDT_MAX_SIZE)));
@@ -1021,7 +1020,7 @@ static void *spapr_build_fdt(sPAPRMachineState *spapr,
_FDT(fdt_setprop_cell(fdt, 0, "#size-cells", 2));
/* /interrupt controller */
- spapr_dt_xics(DIV_ROUND_UP(max_cpus * smt, smp_threads), fdt,
PHANDLE_XICP);
+ spapr_dt_xics(ppc_cpu_dt_id_from_index(max_cpus), fdt, PHANDLE_XICP);
ret = spapr_populate_memory(spapr, fdt);
if (ret < 0) {
@@ -1977,7 +1976,6 @@ static void spapr_init_cpus(sPAPRMachineState *spapr)
MachineState *machine = MACHINE(spapr);
MachineClass *mc = MACHINE_GET_CLASS(machine);
char *type = spapr_get_cpu_core_type(machine->cpu_model);
- int smt = kvmppc_smt_threads();
const CPUArchIdList *possible_cpus;
int boot_cores_nr = smp_cpus / smp_threads;
int i;
@@ -2014,7 +2012,7 @@ static void spapr_init_cpus(sPAPRMachineState *spapr)
sPAPRDRConnector *drc =
spapr_dr_connector_new(OBJECT(spapr),
SPAPR_DR_CONNECTOR_TYPE_CPU,
- (core_id / smp_threads) * smt);
+ ppc_cpu_dt_id_from_index(core_id));
qemu_register_reset(spapr_drc_reset, drc);
}
diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
index 401e10e7dad8..47fe6c64698f 100644
--- a/target/ppc/cpu.h
+++ b/target/ppc/cpu.h
@@ -2529,4 +2529,21 @@ int ppc_get_vcpu_dt_id(PowerPCCPU *cpu);
PowerPCCPU *ppc_get_vcpu_by_dt_id(int cpu_dt_id);
void ppc_maybe_bswap_register(CPUPPCState *env, uint8_t *mem_buf, int len);
+
+#if !defined(CONFIG_USER_ONLY)
+#include "sysemu/cpus.h"
+#include "target/ppc/kvm_ppc.h"
+
+static inline int ppc_cpu_dt_id_from_index(int cpu_index)
+{
+ /* POWER HV support has an historical limitation that different threads
+ * on a single core cannot be in different guests at the same time. In
+ * order to allow KVM to assign guest threads to host cores accordingly,
+ * CPU device tree ids are spaced by the number of threads per host cores.
+ */
+ return (cpu_index / smp_threads) * kvmppc_smt_threads()
+ + (cpu_index % smp_threads);
+}
+#endif
+
#endif /* PPC_CPU_H */
diff --git a/target/ppc/translate_init.c b/target/ppc/translate_init.c
index 56a0ab22cfbe..837a9a496a65 100644
--- a/target/ppc/translate_init.c
+++ b/target/ppc/translate_init.c
@@ -9851,8 +9851,7 @@ static void ppc_cpu_realizefn(DeviceState *dev, Error
**errp)
}
#if !defined(CONFIG_USER_ONLY)
- cpu->cpu_dt_id = (cs->cpu_index / smp_threads) * max_smt
- + (cs->cpu_index % smp_threads);
+ cpu->cpu_dt_id = ppc_cpu_dt_id_from_index(cs->cpu_index);
if (kvm_enabled() && !kvm_vcpu_id_is_valid(cpu->cpu_dt_id)) {
error_setg(errp, "Can't create CPU with id %d in KVM", cpu->cpu_dt_id);
