From: Tao Cui <[email protected]> Advertising pv features to the guest affects the migration stream. Add a no_pv_feature compat flag so the behavior can be gated per machine version: LoongArchCPU gets a bool field, and the virt machine gains a LoongArchVirtMachineClass field that defaults the CPU flag per version.
kvm_cpu_check_pv_features() skips populating pv features when the flag is set. The 11.1 machine type keeps pv advertisement off (no_pv_feature is true, preserving the previous behavior); from the new 11.2 machine type it is on by default. Signed-off-by: Tao Cui <[email protected]> --- hw/loongarch/virt.c | 14 +++++++++++++- include/hw/loongarch/virt.h | 9 ++++++++- target/loongarch/cpu.h | 1 + target/loongarch/kvm/kvm.c | 5 +++++ 4 files changed, 27 insertions(+), 2 deletions(-) diff --git a/hw/loongarch/virt.c b/hw/loongarch/virt.c index 6693dea647..53c84c8def 100644 --- a/hw/loongarch/virt.c +++ b/hw/loongarch/virt.c @@ -955,6 +955,8 @@ static void virt_init(MachineState *machine) machine->cpu_type); exit(EXIT_FAILURE); } + LOONGARCH_CPU(cpuobj)->no_pv_feature = + LOONGARCH_VIRT_MACHINE_GET_CLASS(lvms)->no_pv_feature; qdev_realize_and_unref(DEVICE(cpuobj), NULL, &error_fatal); } virt_check_dmsi(machine); @@ -1584,6 +1586,7 @@ static const TypeInfo virt_machine_info = { .parent = TYPE_MACHINE, .abstract = true, .instance_size = sizeof(LoongArchVirtMachineState), + .class_size = sizeof(LoongArchVirtMachineClass), .class_init = virt_class_init, .instance_init = virt_initfn, .instance_finalize = virt_instance_finalize, @@ -1601,6 +1604,15 @@ static void machvirt_machine_init(void) type_init(machvirt_machine_init); static void virt_machine_11_1_options(MachineClass *mc) +{ + LoongArchVirtMachineClass *vmc = LOONGARCH_VIRT_MACHINE_CLASS(mc); + + /* pv feature advertisement is enabled from 11.2; keep 11.1 unchanged */ + vmc->no_pv_feature = true; +} +DEFINE_VIRT_MACHINE(11, 1) + +static void virt_machine_11_2_options(MachineClass *mc) { } -DEFINE_VIRT_MACHINE_AS_LATEST(11, 1) +DEFINE_VIRT_MACHINE_AS_LATEST(11, 2) diff --git a/include/hw/loongarch/virt.h b/include/hw/loongarch/virt.h index d39a9bbf5d..cf8d9e1fd2 100644 --- a/include/hw/loongarch/virt.h +++ b/include/hw/loongarch/virt.h @@ -130,8 +130,15 @@ struct LoongArchVirtMachineState { bool highmem_mmio; }; +struct LoongArchVirtMachineClass { + MachineClass parent_obj; + + bool no_pv_feature; /* compat: 11.1 and older do not advertise pv features */ +}; + #define TYPE_LOONGARCH_VIRT_MACHINE MACHINE_TYPE_NAME("virt") -OBJECT_DECLARE_SIMPLE_TYPE(LoongArchVirtMachineState, LOONGARCH_VIRT_MACHINE) +OBJECT_DECLARE_TYPE(LoongArchVirtMachineState, LoongArchVirtMachineClass, + LOONGARCH_VIRT_MACHINE) void virt_acpi_setup(LoongArchVirtMachineState *lvms); void virt_fdt_setup(LoongArchVirtMachineState *lvms); diff --git a/target/loongarch/cpu.h b/target/loongarch/cpu.h index ad30c73167..11bbb5f36e 100644 --- a/target/loongarch/cpu.h +++ b/target/loongarch/cpu.h @@ -447,6 +447,7 @@ struct ArchCPU { OnOffAuto msgint; OnOffAuto kvm_pv_ipi; OnOffAuto kvm_steal_time; + bool no_pv_feature; /* compat: do not advertise KVM pv features */ int32_t socket_id; /* socket-id of this CPU */ int32_t core_id; /* core-id of this CPU */ int32_t thread_id; /* thread-id of this CPU */ diff --git a/target/loongarch/kvm/kvm.c b/target/loongarch/kvm/kvm.c index c557ee3c3d..878914928b 100644 --- a/target/loongarch/kvm/kvm.c +++ b/target/loongarch/kvm/kvm.c @@ -1119,6 +1119,11 @@ static int kvm_cpu_check_pv_features(CPUState *cs, Error **errp) CPULoongArchState *env = cpu_env(cs); bool kvm_supported; + /* compat: older machine types do not advertise pv features to the guest */ + if (cpu->no_pv_feature) { + return 0; + } + kvm_supported = kvm_feature_supported(cs, LOONGARCH_FEATURE_PV_IPI); if (cpu->kvm_pv_ipi == ON_OFF_AUTO_ON) { if (!kvm_supported) { -- 2.43.0
