Reflect the ACPI CPU hotplug `is_{present, enabled}` states in the `_STA.PRES`
(presence) and `_STA.ENA` (enabled) bits when the guest kernel evaluates the
ACPI `_STA` method during initialization, as well as when vCPUs are hot-plugged
or hot-unplugged. The presence of unplugged vCPUs may need to be deliberately
*simulated* at the ACPI level to maintain a *persistent* view of vCPUs for the
guest kernel.
Signed-off-by: Salil Mehta <salil.me...@huawei.com>
---
hw/acpi/cpu.c | 26 ++++++++++++++++++++++----
1 file changed, 22 insertions(+), 4 deletions(-)
diff --git a/hw/acpi/cpu.c b/hw/acpi/cpu.c
index 700aa855e9..23ea2b9c70 100644
--- a/hw/acpi/cpu.c
+++ b/hw/acpi/cpu.c
@@ -63,10 +63,11 @@ static uint64_t cpu_hotplug_rd(void *opaque, hwaddr addr,
unsigned size)
cdev = &cpu_st->devs[cpu_st->selector];
switch (addr) {
case ACPI_CPU_FLAGS_OFFSET_RW: /* pack and return is_* fields */
- val |= cdev->cpu ? 1 : 0;
+ val |= cdev->is_enabled ? 1 : 0;
val |= cdev->is_inserting ? 2 : 0;
val |= cdev->is_removing ? 4 : 0;
val |= cdev->fw_remove ? 16 : 0;
+ val |= cdev->is_present ? 32 : 0;
trace_cpuhp_acpi_read_flags(cpu_st->selector, val);
break;
case ACPI_CPU_CMD_DATA_OFFSET_RW:
@@ -376,6 +377,7 @@ const VMStateDescription vmstate_cpu_hotplug = {
#define CPU_REMOVE_EVENT "CRMV"
#define CPU_EJECT_EVENT "CEJ0"
#define CPU_FW_EJECT_EVENT "CEJF"
+#define CPU_PRESENT "CPRS"
void build_cpus_aml(Aml *table, MachineState *machine, CPUHotplugFeatures opts,
build_madt_cpu_fn build_madt_cpu, hwaddr base_addr,
@@ -436,7 +438,9 @@ void build_cpus_aml(Aml *table, MachineState *machine,
CPUHotplugFeatures opts,
aml_append(field, aml_named_field(CPU_EJECT_EVENT, 1));
/* tell firmware to do device eject, write only */
aml_append(field, aml_named_field(CPU_FW_EJECT_EVENT, 1));
- aml_append(field, aml_reserved_field(3));
+ /* 1 if present, read only */
+ aml_append(field, aml_named_field(CPU_PRESENT, 1));
+ aml_append(field, aml_reserved_field(2));
aml_append(field, aml_named_field(CPU_COMMAND, 8));
aml_append(cpu_ctrl_dev, field);
@@ -466,6 +470,7 @@ void build_cpus_aml(Aml *table, MachineState *machine,
CPUHotplugFeatures opts,
Aml *ctrl_lock = aml_name("%s.%s", cphp_res_path, CPU_LOCK);
Aml *cpu_selector = aml_name("%s.%s", cphp_res_path, CPU_SELECTOR);
Aml *is_enabled = aml_name("%s.%s", cphp_res_path, CPU_ENABLED);
+ Aml *is_present = aml_name("%s.%s", cphp_res_path, CPU_PRESENT);
Aml *cpu_cmd = aml_name("%s.%s", cphp_res_path, CPU_COMMAND);
Aml *cpu_data = aml_name("%s.%s", cphp_res_path, CPU_DATA);
Aml *ins_evt = aml_name("%s.%s", cphp_res_path, CPU_INSERT_EVENT);
@@ -494,13 +499,26 @@ void build_cpus_aml(Aml *table, MachineState *machine,
CPUHotplugFeatures opts,
{
Aml *idx = aml_arg(0);
Aml *sta = aml_local(0);
+ Aml *ifctx2;
+ Aml *else_ctx;
aml_append(method, aml_acquire(ctrl_lock, 0xFFFF));
aml_append(method, aml_store(idx, cpu_selector));
aml_append(method, aml_store(zero, sta));
- ifctx = aml_if(aml_equal(is_enabled, one));
+ ifctx = aml_if(aml_equal(is_present, one));
{
- aml_append(ifctx, aml_store(aml_int(0xF), sta));
+ ifctx2 = aml_if(aml_equal(is_enabled, one));
+ {
+ /* cpu is present and enabled */
+ aml_append(ifctx2, aml_store(aml_int(0xF), sta));
+ }
+ aml_append(ifctx, ifctx2);
+ else_ctx = aml_else();
+ {
+ /* cpu is present but disabled */
+ aml_append(else_ctx, aml_store(aml_int(0xD), sta));
+ }
+ aml_append(ifctx, else_ctx);
}
aml_append(method, ifctx);
aml_append(method, aml_release(ctrl_lock));
--
2.34.1
