On 2020-11-24 4:25 a.m., Igor Mammedov wrote:
If firmware negotiates ICH9_LPC_SMI_F_CPU_HOT_UNPLUG_BIT feature,
OSPM on CPU eject will set bit #4 in CPU hotplug block for to be
ejected CPU to mark it for removal by firmware and trigger SMI
upcall to let firmware do actual eject.
Signed-off-by: Igor Mammedov <imamm...@redhat.com>
---
PS:
- abuse 5.1 machine type for now to turn off unplug feature
(it will be moved to 5.2 machine type once new merge window is open)
---
include/hw/acpi/cpu.h | 2 ++
docs/specs/acpi_cpu_hotplug.txt | 11 +++++++++--
hw/acpi/cpu.c | 18 ++++++++++++++++--
hw/i386/acpi-build.c | 5 +++++
hw/i386/pc.c | 1 +
hw/isa/lpc_ich9.c | 2 +-
6 files changed, 34 insertions(+), 5 deletions(-)
diff --git a/include/hw/acpi/cpu.h b/include/hw/acpi/cpu.h
index 0eeedaa491..999caaf510 100644
--- a/include/hw/acpi/cpu.h
+++ b/include/hw/acpi/cpu.h
@@ -22,6 +22,7 @@ typedef struct AcpiCpuStatus {
uint64_t arch_id;
bool is_inserting;
bool is_removing;
+ bool fw_remove;
uint32_t ost_event;
uint32_t ost_status;
} AcpiCpuStatus;
@@ -50,6 +51,7 @@ void cpu_hotplug_hw_init(MemoryRegion *as, Object *owner,
typedef struct CPUHotplugFeatures {
bool acpi_1_compatible;
bool has_legacy_cphp;
+ bool fw_unplugs_cpu;
const char *smi_path;
} CPUHotplugFeatures;
diff --git a/docs/specs/acpi_cpu_hotplug.txt b/docs/specs/acpi_cpu_hotplug.txt
index 9bb22d1270..f68ef6e06c 100644
--- a/docs/specs/acpi_cpu_hotplug.txt
+++ b/docs/specs/acpi_cpu_hotplug.txt
@@ -57,7 +57,11 @@ read access:
It's valid only when bit 0 is set.
2: Device remove event, used to distinguish device for which
no device eject request to OSPM was issued.
- 3-7: reserved and should be ignored by OSPM
+ 3: reserved and should be ignored by OSPM
+ 4: if set to 1, OSPM requests firmware to perform device eject,
+ firmware shall clear this event by writing 1 into it before
+ performing device eject> + 5-7: reserved and should be
ignored by OSPM
[0x5-0x7] reserved
[0x8] Command data: (DWORD access)
contains 0 unless value last stored in 'Command field' is one of:
@@ -82,7 +86,10 @@ write access:
selected CPU device
3: if set to 1 initiates device eject, set by OSPM when it
triggers CPU device removal and calls _EJ0 method
- 4-7: reserved, OSPM must clear them before writing to register
+ 4: if set to 1 OSPM hands over device eject to firmware,
+ Firmware shall issue device eject request as described above
+ (bit #3) and OSPM should not touch device eject bit (#3),
+ 5-7: reserved, OSPM must clear them before writing to register
[0x5] Command field: (1 byte access)
value:
0: selects a CPU device with inserting/removing events and
diff --git a/hw/acpi/cpu.c b/hw/acpi/cpu.c
index f099b50927..09d2f20dae 100644
--- a/hw/acpi/cpu.c
+++ b/hw/acpi/cpu.c
@@ -71,6 +71,7 @@ static uint64_t cpu_hotplug_rd(void *opaque, hwaddr addr,
unsigned size)
val |= cdev->cpu ? 1 : 0;
val |= cdev->is_inserting ? 2 : 0;
val |= cdev->is_removing ? 4 : 0;
+ val |= cdev->fw_remove ? 16 : 0;
I might be missing something but I don't see where cdev->fw_remove is being
set. We do set cdev->is_removing in acpi_cpu_unplug_request_cb() so AFAICS
we would always end up setting this bit:
val |= cdev->is_removing ? 4 : 0;
Also, if cdev->fw_remove and cdev->is_removing are both true, val would be
(4 | 16). I'm guessing that in that case the AML determines which case gets
handled but it might make sense to set just one of these?
trace_cpuhp_acpi_read_flags(cpu_st->selector, val);
break;
case ACPI_CPU_CMD_DATA_OFFSET_RW:
@@ -148,6 +149,8 @@ static void cpu_hotplug_wr(void *opaque, hwaddr addr,
uint64_t data,
hotplug_ctrl = qdev_get_hotplug_handler(dev);
hotplug_handler_unplug(hotplug_ctrl, dev, NULL);
object_unparent(OBJECT(dev));
+ } else if (data & 16) {
+ cdev->fw_remove = !cdev->fw_remove;
}
break;
case ACPI_CPU_CMD_OFFSET_WR:
@@ -332,6 +335,7 @@ const VMStateDescription vmstate_cpu_hotplug = {
#define CPU_INSERT_EVENT "CINS"
#define CPU_REMOVE_EVENT "CRMV"
#define CPU_EJECT_EVENT "CEJ0"
+#define CPU_FW_EJECT_EVENT "CEJF"
void build_cpus_aml(Aml *table, MachineState *machine, CPUHotplugFeatures opts,
hwaddr io_base,
@@ -384,7 +388,10 @@ void build_cpus_aml(Aml *table, MachineState *machine,
CPUHotplugFeatures opts,
aml_append(field, aml_named_field(CPU_REMOVE_EVENT, 1));
/* initiates device eject, write only */
aml_append(field, aml_named_field(CPU_EJECT_EVENT, 1));
- aml_append(field, aml_reserved_field(4));
+ aml_append(field, aml_reserved_field(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(2));
aml_append(field, aml_named_field(CPU_COMMAND, 8));
aml_append(cpu_ctrl_dev, field);
@@ -419,6 +426,7 @@ void build_cpus_aml(Aml *table, MachineState *machine, CPUHotplugFeatures opts,
Aml *ins_evt = aml_name("%s.%s", cphp_res_path, CPU_INSERT_EVENT);
Aml *rm_evt = aml_name("%s.%s", cphp_res_path, CPU_REMOVE_EVENT);
Aml *ej_evt = aml_name("%s.%s", cphp_res_path, CPU_EJECT_EVENT);
+ Aml *fw_ej_evt = aml_name("%s.%s", cphp_res_path, CPU_FW_EJECT_EVENT);
aml_append(cpus_dev, aml_name_decl("_HID", aml_string("ACPI0010")));
aml_append(cpus_dev, aml_name_decl("_CID", aml_eisaid("PNP0A05")));
@@ -461,7 +469,13 @@ void build_cpus_aml(Aml *table, MachineState *machine,
CPUHotplugFeatures opts,
aml_append(method, aml_acquire(ctrl_lock, 0xFFFF));
aml_append(method, aml_store(idx, cpu_selector));
- aml_append(method, aml_store(one, ej_evt));
+ if (opts.fw_unplugs_cpu) {
+ aml_append(method, aml_store(one, fw_ej_evt));
+ aml_append(method, aml_store(aml_int(OVMF_CPUHP_SMI_CMD),
+ aml_name("%s", opts.smi_path)));
+ } else {
+ aml_append(method, aml_store(one, ej_evt));
+ }
My knowledge of AML is rather rudimentary but this looks mostly reasonable to
me.
One question: the corresponding code for CPU hotplug does not send an SMI_CMD.
Why the difference?
aml_append(while_ctx,
aml_store(aml_derefof(aml_index(new_cpus, cpu_idx)),
uid));
aml_append(while_ctx,
aml_call2(CPU_NOTIFY_METHOD, uid, dev_chk));
aml_append(while_ctx, aml_store(uid, cpu_selector));
aml_append(while_ctx, aml_store(one, ins_evt));
aml_append(while_ctx, aml_increment(cpu_idx));
aml_append(method, aml_release(ctrl_lock));
}
aml_append(cpus_dev, method);
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 1f5c211245..475e76f514 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -96,6 +96,7 @@ typedef struct AcpiPmInfo {
bool s4_disabled;
bool pcihp_bridge_en;
bool smi_on_cpuhp;
+ bool smi_on_cpu_unplug;
bool pcihp_root_en;
uint8_t s4_val;
AcpiFadtData fadt;
@@ -197,6 +198,7 @@ static void acpi_get_pm_info(MachineState *machine,
AcpiPmInfo *pm)
pm->pcihp_io_base = 0;
pm->pcihp_io_len = 0;
pm->smi_on_cpuhp = false;
+ pm->smi_on_cpu_unplug = false;
assert(obj);
init_common_fadt_data(machine, obj, &pm->fadt);
@@ -220,6 +222,8 @@ static void acpi_get_pm_info(MachineState *machine,
AcpiPmInfo *pm)
pm->cpu_hp_io_base = ICH9_CPU_HOTPLUG_IO_BASE;
pm->smi_on_cpuhp =
!!(smi_features & BIT_ULL(ICH9_LPC_SMI_F_CPU_HOTPLUG_BIT));
+ pm->smi_on_cpu_unplug =
+ !!(smi_features & BIT_ULL(ICH9_LPC_SMI_F_CPU_HOT_UNPLUG_BIT));
}
/* The above need not be conditional on machine type because the reset port
@@ -1582,6 +1586,7 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
CPUHotplugFeatures opts = {
.acpi_1_compatible = true, .has_legacy_cphp = true,
.smi_path = pm->smi_on_cpuhp ? "\\_SB.PCI0.SMI0.SMIC" : NULL,
+ .fw_unplugs_cpu = pm->smi_on_cpu_unplug,
};
build_cpus_aml(dsdt, machine, opts, pm->cpu_hp_io_base,
"\\_SB.PCI0", "\\_GPE._E02");
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 17b514d1da..2952a00fe6 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -99,6 +99,7 @@
GlobalProperty pc_compat_5_1[] = {
{ "ICH9-LPC", "x-smi-cpu-hotplug", "off" },
+ { "ICH9-LPC", "x-smi-cpu-hotunplug", "off" },
};
const size_t pc_compat_5_1_len = G_N_ELEMENTS(pc_compat_5_1);
diff --git a/hw/isa/lpc_ich9.c b/hw/isa/lpc_ich9.c
index 087a18d04d..8c667b7166 100644
--- a/hw/isa/lpc_ich9.c
+++ b/hw/isa/lpc_ich9.c
@@ -770,7 +770,7 @@ static Property ich9_lpc_properties[] = {
DEFINE_PROP_BIT64("x-smi-cpu-hotplug", ICH9LPCState, smi_host_features,
ICH9_LPC_SMI_F_CPU_HOTPLUG_BIT, true),
DEFINE_PROP_BIT64("x-smi-cpu-hotunplug", ICH9LPCState, smi_host_features,
- ICH9_LPC_SMI_F_CPU_HOT_UNPLUG_BIT, false),
+ ICH9_LPC_SMI_F_CPU_HOT_UNPLUG_BIT, true),
DEFINE_PROP_END_OF_LIST(),
};
Thanks for sending out the patch btw. This helped me crystallize some of the
corresponding OVMF code.
Ankur
