* [PATCH v2 1/4] hw/acpi: Increase the number of possible ACPI interrupts
2025-08-21 17:45 [PATCH v2 0/4] Introduce a battery, AC adapter, and lid button Leonid Bloch
@ 2025-08-21 17:45 ` Leonid Bloch
2025-08-26 12:47 ` Igor Mammedov
2025-08-21 17:45 ` [PATCH v2 2/4] hw/acpi: Introduce the QEMU Battery Leonid Bloch
` (3 subsequent siblings)
4 siblings, 1 reply; 7+ messages in thread
From: Leonid Bloch @ 2025-08-21 17:45 UTC (permalink / raw)
To: Michael S . Tsirkin, Igor Mammedov, Ani Sinha, Paolo Bonzini,
Richard Henderson, Eduardo Habkost, Eric Blake, Markus Armbruster,
Marcel Apfelbaum, Dmitry Fleytman
Cc: Leonid Bloch, qemu-devel
Increase the number of possible ACPI interrupts from 8, to the maximum
available: 64 by default.
Signed-off-by: Leonid Bloch <lb.workbox@gmail.com>
---
hw/acpi/core.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/hw/acpi/core.c b/hw/acpi/core.c
index 58f8964e13..447ff07878 100644
--- a/hw/acpi/core.c
+++ b/hw/acpi/core.c
@@ -729,19 +729,32 @@ uint32_t acpi_gpe_ioport_readb(ACPIREGS *ar, uint32_t addr)
void acpi_send_gpe_event(ACPIREGS *ar, qemu_irq irq,
AcpiEventStatusBits status)
{
- ar->gpe.sts[0] |= status;
+ int i;
+
+ AcpiEventStatusBits st = status;
+ for (i = 0; i < ar->gpe.len / 2; i++) {
+ ar->gpe.sts[i] |= st;
+ st >>= (sizeof(ar->gpe.sts[0]) * CHAR_BIT);
+ }
+
acpi_update_sci(ar, irq);
}
void acpi_update_sci(ACPIREGS *regs, qemu_irq irq)
{
int sci_level, pm1a_sts;
+ uint64_t gpe_sci = 0;
+ int i;
pm1a_sts = acpi_pm1_evt_get_sts(regs);
+ for (i = 0; i < regs->gpe.len / 2; i++) {
+ gpe_sci |= (regs->gpe.sts[i] & regs->gpe.en[i]);
+ }
+
sci_level = ((pm1a_sts &
regs->pm1.evt.en & ACPI_BITMASK_PM1_COMMON_ENABLED) != 0) ||
- ((regs->gpe.sts[0] & regs->gpe.en[0]) != 0);
+ (gpe_sci != 0);
qemu_set_irq(irq, sci_level);
--
2.50.1
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [PATCH v2 1/4] hw/acpi: Increase the number of possible ACPI interrupts
2025-08-21 17:45 ` [PATCH v2 1/4] hw/acpi: Increase the number of possible ACPI interrupts Leonid Bloch
@ 2025-08-26 12:47 ` Igor Mammedov
0 siblings, 0 replies; 7+ messages in thread
From: Igor Mammedov @ 2025-08-26 12:47 UTC (permalink / raw)
To: Leonid Bloch
Cc: Michael S . Tsirkin, Ani Sinha, Paolo Bonzini, Richard Henderson,
Eduardo Habkost, Eric Blake, Markus Armbruster, Marcel Apfelbaum,
Dmitry Fleytman, qemu-devel
On Thu, 21 Aug 2025 20:45:49 +0300
Leonid Bloch <lb.workbox@gmail.com> wrote:
> Increase the number of possible ACPI interrupts from 8, to the maximum
> available: 64 by default.
for piix4 we have 'GPE_LEN 4', which gives us 2 bitmaps (STS/EN) 16bit each.
For ICH9_PMIO_GPE0_LEN 16 => 8bytes/bitmap
so numbers above would vary on used machine type
also commit message should mention why this is needed.
>
> Signed-off-by: Leonid Bloch <lb.workbox@gmail.com>
> ---
> hw/acpi/core.c | 17 +++++++++++++++--
> 1 file changed, 15 insertions(+), 2 deletions(-)
>
> diff --git a/hw/acpi/core.c b/hw/acpi/core.c
> index 58f8964e13..447ff07878 100644
> --- a/hw/acpi/core.c
> +++ b/hw/acpi/core.c
> @@ -729,19 +729,32 @@ uint32_t acpi_gpe_ioport_readb(ACPIREGS *ar, uint32_t addr)
> void acpi_send_gpe_event(ACPIREGS *ar, qemu_irq irq,
> AcpiEventStatusBits status)
> {
> - ar->gpe.sts[0] |= status;
> + int i;
> +
> + AcpiEventStatusBits st = status;
newline here and remove newline above
> + for (i = 0; i < ar->gpe.len / 2; i++) {
> + ar->gpe.sts[i] |= st;
> + st >>= (sizeof(ar->gpe.sts[0]) * CHAR_BIT);
perhaps use TYPE_WIDTH()
> + }
>
> acpi_update_sci(ar, irq);
> }
>
> void acpi_update_sci(ACPIREGS *regs, qemu_irq irq)
> {
> int sci_level, pm1a_sts;
> + uint64_t gpe_sci = 0;
> + int i;
>
> pm1a_sts = acpi_pm1_evt_get_sts(regs);
>
> + for (i = 0; i < regs->gpe.len / 2; i++) {
> + gpe_sci |= (regs->gpe.sts[i] & regs->gpe.en[i]);
^^^
make it bool and then !!(regs->gpe.sts[i] & regs->gpe.en[i])
> + }
or maybe instead of opencoding bitmaps, use bitmap API from bitops.h
> sci_level = ((pm1a_sts &
> regs->pm1.evt.en & ACPI_BITMASK_PM1_COMMON_ENABLED) != 0) ||
> - ((regs->gpe.sts[0] & regs->gpe.en[0]) != 0);
> + (gpe_sci != 0);
>
> qemu_set_irq(irq, sci_level);
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v2 2/4] hw/acpi: Introduce the QEMU Battery
2025-08-21 17:45 [PATCH v2 0/4] Introduce a battery, AC adapter, and lid button Leonid Bloch
2025-08-21 17:45 ` [PATCH v2 1/4] hw/acpi: Increase the number of possible ACPI interrupts Leonid Bloch
@ 2025-08-21 17:45 ` Leonid Bloch
2025-08-21 17:45 ` [PATCH v2 3/4] hw/acpi: Introduce the QEMU AC adapter Leonid Bloch
` (2 subsequent siblings)
4 siblings, 0 replies; 7+ messages in thread
From: Leonid Bloch @ 2025-08-21 17:45 UTC (permalink / raw)
To: Michael S . Tsirkin, Igor Mammedov, Ani Sinha, Paolo Bonzini,
Richard Henderson, Eduardo Habkost, Eric Blake, Markus Armbruster,
Marcel Apfelbaum, Dmitry Fleytman
Cc: Leonid Bloch, qemu-devel
The battery device communicates battery state to the guest via ACPI.
It supports two modes of operation:
1. QMP control mode (default): Battery state is controlled programmatically
via QMP commands, making the device deterministic and migration-safe.
2. Host mirroring mode (optional): The device reflects the host's battery
state from sysfs. Probing occurs on guest ACPI requests and at timed
intervals (default 2 seconds, configurable via 'probe_interval' property
in milliseconds). State changes trigger ACPI notifications to the guest.
Properties:
- 'use-qmp': Enable QMP control mode (default: true)
- 'enable-sysfs': Enable host battery mirroring (default: false)
- 'probe_interval': Probe interval in ms for sysfs mode (default: 2000)
- 'sysfs_path': Override default sysfs path /sys/class/power_supply/
The device implements the ACPI_DEV_AML_IF interface to generate its
own AML code, placing the BAT0 device directly under \_SB scope as
per ACPI specification.
QMP commands:
- battery-set-state: Set battery state (present, charging, capacity, rate)
- query-battery: Query current battery state
This allows testing without host battery access and provides a stable
interface for virtualization management systems.
Signed-off-by: Leonid Bloch <lb.workbox@gmail.com>
Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
---
MAINTAINERS | 6 +
docs/specs/battery.rst | 225 ++++++++
docs/specs/index.rst | 1 +
hw/acpi/Kconfig | 4 +
hw/acpi/battery.c | 735 +++++++++++++++++++++++++++
hw/acpi/meson.build | 1 +
hw/acpi/trace-events | 5 +
hw/i386/Kconfig | 1 +
hw/i386/acpi-build.c | 1 +
include/hw/acpi/acpi_dev_interface.h | 1 +
include/hw/acpi/battery.h | 33 ++
qapi/acpi.json | 73 +++
12 files changed, 1086 insertions(+)
create mode 100644 docs/specs/battery.rst
create mode 100644 hw/acpi/battery.c
create mode 100644 include/hw/acpi/battery.h
diff --git a/MAINTAINERS b/MAINTAINERS
index a07086ed76..51af9b7366 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2921,6 +2921,12 @@ F: hw/vmapple/*
F: include/hw/vmapple/*
F: docs/system/arm/vmapple.rst
+Battery
+M: Leonid Bloch <lb.workbox@gmail.com>
+S: Maintained
+F: hw/acpi/battery.*
+F: docs/specs/battery.rst
+
Subsystems
----------
Overall Audio backends
diff --git a/docs/specs/battery.rst b/docs/specs/battery.rst
new file mode 100644
index 0000000000..e426b91ea5
--- /dev/null
+++ b/docs/specs/battery.rst
@@ -0,0 +1,225 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+==============
+Battery Device
+==============
+
+The battery device provides battery state information to the guest. It supports
+two operating modes:
+
+1. **QMP Control Mode** (default): Battery state is controlled via QMP commands,
+ providing deterministic control for testing and migration safety.
+2. **Sysfs Mode**: Battery state mirrors the host's physical battery, useful
+ for desktop virtualization where the guest should see the host's battery.
+
+Configuration
+-------------
+
+The battery device is created as an ISA device using ``-device battery``.
+
+Operating Modes
+~~~~~~~~~~~~~~~
+
+**QMP Control Mode** (``use-qmp=true``, default)
+ Battery state is controlled via QMP commands. This mode is recommended for:
+
+ * Production environments requiring migration support
+ * Testing with predictable battery states
+ * Environments without host battery access
+ * Security-sensitive deployments
+
+**Sysfs Mode** (``enable-sysfs=true``)
+ Battery mirrors the host's physical battery. This mode is useful for:
+
+ * Desktop virtualization on laptops
+ * Development and testing with real battery behavior
+
+ Note: Sysfs mode reads host files and runs timers, which may impact
+ security and migration. Use with caution in production.
+
+Properties
+~~~~~~~~~~
+
+``ioport`` (default: 0x530)
+ I/O port base address for the battery device registers.
+
+``use-qmp`` (default: true)
+ Enable QMP control mode. When true, battery state is controlled via
+ QMP commands. Cannot be used together with ``enable-sysfs=true``.
+
+``enable-sysfs`` (default: false)
+ Enable sysfs mode to mirror the host's battery. Cannot be used together
+ with ``use-qmp=true``.
+
+``probe_interval`` (default: 2000)
+ Time interval between periodic probes in milliseconds (sysfs mode only).
+ A zero value disables the periodic probes, and makes the battery state
+ updates occur on guest requests only.
+
+``sysfs_path`` (default: auto-detected)
+ Path to the host's battery sysfs directory (sysfs mode only). If not
+ specified, the device will automatically detect the battery from
+ ``/sys/class/power_supply/``. This property allows overriding the default
+ path if:
+
+ * The sysfs path differs from the standard location
+ * A different battery needs to be probed
+ * A "fake" host battery is to be provided for testing
+
+Host Battery Detection
+----------------------
+
+The host's battery information is taken from the sysfs battery data,
+located in::
+
+ /sys/class/power_supply/[device of type "Battery"]
+
+The device automatically scans for the first available battery device
+with type "Battery" in the power_supply directory.
+
+ACPI Interface
+--------------
+
+The battery device exposes itself as an ACPI battery device with:
+
+* **_HID**: ``PNP0C0A`` (Control Method Battery)
+* **Device path**: ``\_SB.BAT0``
+
+The device implements standard ACPI battery methods:
+
+``_STA`` (Status)
+ Returns the battery presence status.
+
+``_BIF`` (Battery Information)
+ Returns static battery information including design capacity,
+ technology, and model information.
+
+``_BST`` (Battery Status)
+ Returns dynamic battery status including current state
+ (charging/discharging), present rate, and remaining capacity.
+
+I/O Interface
+-------------
+
+The battery device exposes 12 bytes of I/O space at the configured
+I/O port address with the following layout:
+
+* **Bytes 0-3**: Battery state (DWORD)
+
+ * 1 = Discharging
+ * 2 = Charging
+
+* **Bytes 4-7**: Battery rate (DWORD)
+
+ Current charge/discharge rate normalized to design capacity.
+
+* **Bytes 8-11**: Battery charge (DWORD)
+
+ Current battery charge level normalized to design capacity.
+
+All values are normalized where the design capacity equals 10000 units.
+Unknown values are represented as 0xFFFFFFFF.
+
+ACPI Notifications
+------------------
+
+The battery device generates ACPI notifications through GPE events:
+
+* **GPE._E07**: Device Check (0x01) - Battery insertion/removal
+* **GPE._E08**: Status Change (0x80) - Battery state change
+* **GPE._E09**: Information Change (0x81) - Battery information update
+
+QMP Commands
+------------
+
+When using QMP control mode (default), the following commands are available:
+
+``battery-set-state``
+ Set the battery state. Parameters:
+
+ * ``present``: Whether the battery is present (boolean)
+ * ``charging``: Whether the battery is charging (boolean)
+ * ``discharging``: Whether the battery is discharging (boolean)
+ * ``charge-percent``: Battery charge percentage 0-100 (integer)
+ * ``rate``: Charge/discharge rate in mW (optional integer)
+
+ Example::
+
+ -> { "execute": "battery-set-state",
+ "arguments": { "state": {
+ "present": true,
+ "charging": true,
+ "discharging": false,
+ "charge-percent": 85,
+ "rate": 500
+ }}}
+ <- { "return": {} }
+
+``query-battery``
+ Query the current battery state. Returns the same fields as above.
+
+ Example::
+
+ -> { "execute": "query-battery" }
+ <- { "return": {
+ "present": true,
+ "charging": true,
+ "discharging": false,
+ "charge-percent": 85,
+ "rate": 500,
+ "design-capacity": 10000
+ }}
+
+Examples
+--------
+
+QMP control mode (default - recommended)::
+
+ # Start with QMP control
+ qemu-system-x86_64 -device battery -qmp tcp:localhost:4444,server,wait=off
+
+ # From another terminal, set battery state via QMP:
+ echo '{"execute":"qmp_capabilities"}
+ {"execute":"battery-set-state",
+ "arguments":{"state":{"present":true,"charging":false,
+ "discharging":true,"charge-percent":42,
+ "rate":500}}}' | \
+ nc -N localhost 4444
+
+Sysfs mode (mirror host battery)::
+
+ # Enable sysfs mode to mirror host battery
+ qemu-system-x86_64 -device battery,use-qmp=false,enable-sysfs=true
+
+ # Custom probe interval (5 seconds)
+ qemu-system-x86_64 -device battery,use-qmp=false,enable-sysfs=true,probe_interval=5000
+
+ # Specific battery path
+ qemu-system-x86_64 -device battery,use-qmp=false,enable-sysfs=true,sysfs_path=/sys/class/power_supply/BAT1
+
+Testing with fake battery::
+
+ # Create fake battery files for testing
+ mkdir -p /tmp/fake_battery
+ echo "Battery" > /tmp/fake_battery/type
+ echo "Discharging" > /tmp/fake_battery/status
+ echo "50" > /tmp/fake_battery/capacity
+ echo "1500000" > /tmp/fake_battery/energy_now # Current energy in μWh
+ echo "3000000" > /tmp/fake_battery/energy_full # Full capacity in μWh
+ echo "500000" > /tmp/fake_battery/power_now # Current power in μW
+
+ # Use fake battery in sysfs mode
+ qemu-system-x86_64 -device battery,use-qmp=false,enable-sysfs=true,sysfs_path=/tmp/fake_battery
+
+ # Update battery state while VM is running (from another terminal)
+ # Change to 75% charging:
+ echo "Charging" > /tmp/fake_battery/status
+ echo "75" > /tmp/fake_battery/capacity
+ echo "2250000" > /tmp/fake_battery/energy_now # 75% of 3000000
+ echo "500000" > /tmp/fake_battery/power_now # Charging rate (500 mW)
+
+ # Change to 25% discharging:
+ echo "Discharging" > /tmp/fake_battery/status
+ echo "25" > /tmp/fake_battery/capacity
+ echo "750000" > /tmp/fake_battery/energy_now # 25% of 3000000
+ echo "300000" > /tmp/fake_battery/power_now # Discharge rate (300 mW)
diff --git a/docs/specs/index.rst b/docs/specs/index.rst
index f19d73c9f6..616e8228cc 100644
--- a/docs/specs/index.rst
+++ b/docs/specs/index.rst
@@ -22,6 +22,7 @@ guest hardware that is specific to QEMU.
acpi_pci_hotplug
acpi_nvdimm
acpi_erst
+ battery
sev-guest-firmware
fw_cfg
fsi
diff --git a/hw/acpi/Kconfig b/hw/acpi/Kconfig
index 1d4e9f0845..64403378bd 100644
--- a/hw/acpi/Kconfig
+++ b/hw/acpi/Kconfig
@@ -83,3 +83,7 @@ config ACPI_ERST
config ACPI_CXL
bool
depends on ACPI
+
+config BATTERY
+ bool
+ depends on ACPI
diff --git a/hw/acpi/battery.c b/hw/acpi/battery.c
new file mode 100644
index 0000000000..5ab3ab7472
--- /dev/null
+++ b/hw/acpi/battery.c
@@ -0,0 +1,735 @@
+/*
+ * QEMU emulated battery device.
+ *
+ * Copyright (c) 2019 Janus Technologies, Inc. (http://janustech.com)
+ *
+ * Authors:
+ * Leonid Bloch <lb.workbox@gmail.com>
+ * Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
+ * Dmitry Fleytman <dmitry.fleytman@gmail.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "trace.h"
+#include "hw/isa/isa.h"
+#include "hw/acpi/acpi.h"
+#include "hw/nvram/fw_cfg.h"
+#include "qapi/error.h"
+#include "qemu/error-report.h"
+#include "hw/qdev-properties.h"
+#include "migration/vmstate.h"
+#include "hw/acpi/acpi_aml_interface.h"
+#include "qapi/qapi-commands-acpi.h"
+
+#include "hw/acpi/battery.h"
+
+#define BATTERY_DEVICE(obj) OBJECT_CHECK(BatteryState, (obj), TYPE_BATTERY)
+
+#define BATTERY_DISCHARGING 0x01 /* ACPI _BST bit 0 */
+#define BATTERY_CHARGING 0x02 /* ACPI _BST bit 1 */
+#define BATTERY_CRITICAL 0x04 /* ACPI _BST bit 2 */
+
+#define SYSFS_PATH "/sys/class/power_supply"
+#define BATTERY_TYPE "Battery"
+
+#define MAX_ALLOWED_STATE_LENGTH 32 /* For convinience when comparing */
+
+#define NORMALIZE_BY_FULL(val, full) \
+ ((full == 0) ? BATTERY_VAL_UNKNOWN \
+ : (uint32_t)(val * BATTERY_FULL_CAP / full))
+
+typedef union bat_metric {
+ uint32_t val;
+ uint8_t acc[4];
+} bat_metric;
+
+typedef struct BatteryState {
+ ISADevice dev;
+ MemoryRegion io;
+ uint16_t ioport;
+ bat_metric state;
+ bat_metric rate;
+ bat_metric charge;
+ uint32_t charge_full;
+ int units; /* 0 - mWh, 1 - mAh */
+ bool use_qmp_control;
+ bool qmp_present;
+ bool qmp_charging;
+ bool qmp_discharging;
+ int qmp_charge_percent;
+ int qmp_rate;
+ bool enable_sysfs;
+
+ QEMUTimer *probe_state_timer;
+ uint64_t probe_state_interval;
+
+ char *bat_path;
+} BatteryState;
+
+/* Access addresses */
+enum acc_addr {
+ bsta_addr0, bsta_addr1, bsta_addr2, bsta_addr3,
+ brte_addr0, brte_addr1, brte_addr2, brte_addr3,
+ bcrg_addr0, bcrg_addr1, bcrg_addr2, bcrg_addr3
+};
+
+/* Files used when the units are: mWh mAh */
+static const char *full_file[] = { "energy_full", "charge_full" };
+static const char *now_file[] = { "energy_now", "charge_now" };
+static const char *rate_file[] = { "power_now", "current_now" };
+
+static const char *stat_file = "status";
+static const char *type_file = "type";
+
+static const char *discharging_states[] = { "Discharging", "Not charging" };
+static const char *charging_states[] = { "Charging", "Full", "Unknown" };
+
+static inline bool battery_file_accessible(char *path, const char *file)
+{
+ char full_path[PATH_MAX];
+ int path_len;
+
+ path_len = snprintf(full_path, PATH_MAX, "%s/%s", path, file);
+ if (path_len < 0 || path_len >= PATH_MAX) {
+ return false;
+ }
+ if (access(full_path, R_OK) == 0) {
+ return true;
+ }
+ return false;
+}
+
+static inline int battery_select_file(char *path, const char **file)
+{
+ if (battery_file_accessible(path, file[0])) {
+ return 0;
+ } else if (battery_file_accessible(path, file[1])) {
+ return 1;
+ } else {
+ return -1;
+ }
+}
+
+static void battery_get_full_charge(BatteryState *s, Error **errp)
+{
+ char file_path[PATH_MAX];
+ int path_len;
+ uint32_t val;
+ FILE *ff;
+
+ path_len = snprintf(file_path, PATH_MAX, "%s/%s", s->bat_path,
+ full_file[s->units]);
+ if (path_len < 0 || path_len >= PATH_MAX) {
+ error_setg(errp, "Full capacity file path is inaccessible.");
+ return;
+ }
+
+ ff = fopen(file_path, "r");
+ if (ff == NULL) {
+ error_setg_errno(errp, errno, "Could not read the full charge file.");
+ return;
+ }
+
+ if (fscanf(ff, "%u", &val) != 1) {
+ error_setg(errp, "Full capacity undetermined.");
+ return;
+ } else {
+ s->charge_full = val;
+ }
+ fclose(ff);
+}
+
+static inline bool battery_is_discharging(char *val)
+{
+ static const int discharging_len = ARRAY_SIZE(discharging_states);
+ int i;
+
+ for (i = 0; i < discharging_len; i++) {
+ if (!strncmp(val, discharging_states[i], MAX_ALLOWED_STATE_LENGTH)) {
+ return true;
+ }
+ }
+ return false;
+}
+
+static inline bool battery_is_charging(char *val)
+{
+ static const int charging_len = ARRAY_SIZE(charging_states);
+ int i;
+
+ for (i = 0; i < charging_len; i++) {
+ if (!strncmp(val, charging_states[i], MAX_ALLOWED_STATE_LENGTH)) {
+ return true;
+ }
+ }
+ return false;
+}
+
+static void battery_get_state(BatteryState *s)
+{
+ char file_path[PATH_MAX];
+ int path_len;
+ char val[MAX_ALLOWED_STATE_LENGTH];
+ FILE *ff;
+
+ path_len = snprintf(file_path, PATH_MAX, "%s/%s", s->bat_path, stat_file);
+ if (path_len < 0 || path_len >= PATH_MAX) {
+ warn_report("Could not read the battery state.");
+ return;
+ }
+
+ ff = fopen(file_path, "r");
+ if (ff == NULL) {
+ warn_report("Could not read the battery state.");
+ return;
+ }
+
+ if (fgets(val, MAX_ALLOWED_STATE_LENGTH, ff) == NULL) {
+ warn_report("Battery state unreadable.");
+ } else {
+ val[strcspn(val, "\n")] = 0;
+ if (battery_is_discharging(val)) {
+ s->state.val = BATTERY_DISCHARGING;
+ } else if (battery_is_charging(val)) {
+ s->state.val = BATTERY_CHARGING;
+ } else {
+ s->state.val = 0;
+ warn_report("Battery state undetermined.");
+ }
+ }
+ fclose(ff);
+}
+
+static void battery_get_rate(BatteryState *s)
+{
+ char file_path[PATH_MAX];
+ int path_len;
+ uint64_t val;
+ FILE *ff;
+
+ path_len = snprintf(file_path, PATH_MAX, "%s/%s", s->bat_path,
+ rate_file[s->units]);
+ if (path_len < 0 || path_len >= PATH_MAX) {
+ warn_report("Could not read the battery rate.");
+ s->rate.val = BATTERY_VAL_UNKNOWN;
+ return;
+ }
+
+ ff = fopen(file_path, "r");
+ if (ff == NULL) {
+ warn_report("Could not read the battery rate.");
+ s->rate.val = BATTERY_VAL_UNKNOWN;
+ return;
+ }
+
+ if (fscanf(ff, "%lu", &val) != 1) {
+ warn_report("Battery rate undetermined.");
+ s->rate.val = BATTERY_VAL_UNKNOWN;
+ } else {
+ s->rate.val = NORMALIZE_BY_FULL(val, s->charge_full);
+ }
+ fclose(ff);
+}
+
+static void battery_get_charge(BatteryState *s)
+{
+ char file_path[PATH_MAX];
+ int path_len;
+ uint64_t val;
+ FILE *ff;
+
+ path_len = snprintf(file_path, PATH_MAX, "%s/%s", s->bat_path,
+ now_file[s->units]);
+ if (path_len < 0 || path_len >= PATH_MAX) {
+ warn_report("Could not read the battery charge.");
+ s->charge.val = BATTERY_VAL_UNKNOWN;
+ return;
+ }
+
+ ff = fopen(file_path, "r");
+ if (ff == NULL) {
+ warn_report("Could not read the battery charge.");
+ s->charge.val = BATTERY_VAL_UNKNOWN;
+ return;
+ }
+
+ if (fscanf(ff, "%lu", &val) != 1) {
+ warn_report("Battery charge undetermined.");
+ s->charge.val = BATTERY_VAL_UNKNOWN;
+ } else {
+ s->charge.val = NORMALIZE_BY_FULL(val, s->charge_full);
+ }
+ fclose(ff);
+}
+
+static void battery_get_dynamic_status(BatteryState *s)
+{
+ if (s->use_qmp_control) {
+ s->state.val = 0;
+ if (s->qmp_present) {
+ if (s->qmp_charging) {
+ s->state.val |= BATTERY_CHARGING;
+ }
+ if (s->qmp_discharging) {
+ s->state.val |= BATTERY_DISCHARGING;
+ }
+ }
+ s->rate.val = s->qmp_rate;
+ s->charge.val = (s->qmp_charge_percent * BATTERY_FULL_CAP) / 100;
+ } else if (s->enable_sysfs) {
+ battery_get_state(s);
+ battery_get_rate(s);
+ battery_get_charge(s);
+ } else {
+ s->state.val = 0;
+ s->rate.val = 0;
+ s->charge.val = 0;
+ }
+
+ trace_battery_get_dynamic_status(s->state.val, s->rate.val, s->charge.val);
+}
+
+static void battery_probe_state(void *opaque)
+{
+ BatteryState *s = opaque;
+
+ uint32_t state_before = s->state.val;
+ uint32_t rate_before = s->rate.val;
+ uint32_t charge_before = s->charge.val;
+
+ battery_get_dynamic_status(s);
+
+ if (state_before != s->state.val || rate_before != s->rate.val ||
+ charge_before != s->charge.val) {
+ Object *obj = object_resolve_path_type("", TYPE_ACPI_DEVICE_IF, NULL);
+ switch (charge_before) {
+ case 0:
+ break; /* Avoid marking initiation as an update */
+ default:
+ acpi_send_event(DEVICE(obj), ACPI_BATTERY_CHANGE_STATUS);
+ }
+ }
+ timer_mod(s->probe_state_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
+ s->probe_state_interval);
+}
+
+static void battery_probe_state_timer_init(BatteryState *s)
+{
+ if (s->enable_sysfs && s->probe_state_interval > 0) {
+ s->probe_state_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL,
+ battery_probe_state, s);
+ timer_mod(s->probe_state_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
+ s->probe_state_interval);
+ }
+}
+
+static bool battery_verify_sysfs(BatteryState *s, char *path)
+{
+ int units;
+ FILE *ff;
+ char type_path[PATH_MAX];
+ int path_len;
+ char val[MAX_ALLOWED_STATE_LENGTH];
+
+ path_len = snprintf(type_path, PATH_MAX, "%s/%s", path, type_file);
+ if (path_len < 0 || path_len >= PATH_MAX) {
+ return false;
+ }
+ ff = fopen(type_path, "r");
+ if (ff == NULL) {
+ return false;
+ }
+
+ if (fgets(val, MAX_ALLOWED_STATE_LENGTH, ff) == NULL) {
+ fclose(ff);
+ return false;
+ } else {
+ val[strcspn(val, "\n")] = 0;
+ if (strncmp(val, BATTERY_TYPE, MAX_ALLOWED_STATE_LENGTH)) {
+ fclose(ff);
+ return false;
+ }
+ }
+ fclose(ff);
+
+ units = battery_select_file(path, full_file);
+
+ if (units < 0) {
+ return false;
+ } else {
+ s->units = units;
+ }
+
+ return (battery_file_accessible(path, now_file[s->units])
+ & battery_file_accessible(path, rate_file[s->units])
+ & battery_file_accessible(path, stat_file));
+}
+
+static bool get_battery_path(DeviceState *dev)
+{
+ BatteryState *s = BATTERY_DEVICE(dev);
+ DIR *dir;
+ struct dirent *ent;
+ char bp[PATH_MAX];
+ int path_len;
+
+ if (s->bat_path) {
+ return battery_verify_sysfs(s, s->bat_path);
+ }
+
+ dir = opendir(SYSFS_PATH);
+ if (dir == NULL) {
+ return false;
+ }
+
+ ent = readdir(dir);
+ while (ent != NULL) {
+ if (ent->d_name[0] != '.') {
+ path_len = snprintf(bp, PATH_MAX, "%s/%s", SYSFS_PATH,
+ ent->d_name);
+ if (path_len < 0 || path_len >= PATH_MAX) {
+ return false;
+ }
+ if (battery_verify_sysfs(s, bp)) {
+ qdev_prop_set_string(dev, BATTERY_PATH_PROP, bp);
+ closedir(dir);
+ return true;
+ }
+ }
+ ent = readdir(dir);
+ }
+ closedir(dir);
+
+ return false;
+}
+
+static void battery_realize(DeviceState *dev, Error **errp)
+{
+ ISADevice *d = ISA_DEVICE(dev);
+ BatteryState *s = BATTERY_DEVICE(dev);
+ FWCfgState *fw_cfg = fw_cfg_find();
+ uint16_t *battery_port;
+ char err_details[0x20] = {};
+
+ trace_battery_realize();
+
+ if (s->use_qmp_control && s->enable_sysfs) {
+ error_setg(errp, "Cannot enable both QMP control and sysfs mode");
+ return;
+ }
+
+ /* Initialize QMP state to sensible defaults when in QMP mode */
+ if (s->use_qmp_control) {
+ s->qmp_present = true;
+ s->qmp_charging = false;
+ s->qmp_discharging = true;
+ s->qmp_charge_percent = 50;
+ s->qmp_rate = 1000; /* 1000 mW discharge rate */
+ }
+
+ if (s->enable_sysfs) {
+ if (!s->bat_path) {
+ strcpy(err_details, " Try using 'sysfs_path='");
+ }
+
+ if (!get_battery_path(dev)) {
+ error_setg(errp, "Battery sysfs path not found or unreadable.%s",
+ err_details);
+ return;
+ }
+ battery_get_full_charge(s, errp);
+ } else {
+ s->charge_full = BATTERY_FULL_CAP;
+ }
+
+ isa_register_ioport(d, &s->io, s->ioport);
+
+ battery_probe_state_timer_init(s);
+
+ if (!fw_cfg) {
+ return;
+ }
+
+ battery_port = g_malloc(sizeof(*battery_port));
+ *battery_port = cpu_to_le16(s->ioport);
+ fw_cfg_add_file(fw_cfg, "etc/battery-port", battery_port,
+ sizeof(*battery_port));
+}
+
+static const Property battery_device_properties[] = {
+ DEFINE_PROP_UINT16(BATTERY_IOPORT_PROP, BatteryState, ioport, 0x530),
+ DEFINE_PROP_BOOL("use-qmp", BatteryState, use_qmp_control, true),
+ DEFINE_PROP_BOOL("enable-sysfs", BatteryState, enable_sysfs, false),
+ DEFINE_PROP_UINT64(BATTERY_PROBE_STATE_INTERVAL, BatteryState,
+ probe_state_interval, 2000),
+ DEFINE_PROP_STRING(BATTERY_PATH_PROP, BatteryState, bat_path),
+};
+
+static const VMStateDescription battery_vmstate = {
+ .name = "battery",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .fields = (VMStateField[]) {
+ VMSTATE_UINT16(ioport, BatteryState),
+ VMSTATE_UINT64(probe_state_interval, BatteryState),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+static void build_battery_aml(AcpiDevAmlIf *adev, Aml *scope)
+{
+ Aml *dev, *field, *method, *pkg;
+ Aml *bat_state, *bat_rate, *bat_charge;
+ Aml *sb_scope;
+ BatteryState *s = BATTERY_DEVICE(adev);
+
+ bat_state = aml_local(0);
+ bat_rate = aml_local(1);
+ bat_charge = aml_local(2);
+
+ sb_scope = aml_scope("\\_SB");
+ dev = aml_device("BAT0");
+ aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0C0A")));
+
+ method = aml_method("_STA", 0, AML_NOTSERIALIZED);
+ aml_append(method, aml_return(aml_int(0x1F)));
+ aml_append(dev, method);
+
+ aml_append(dev, aml_operation_region("DBST", AML_SYSTEM_IO,
+ aml_int(s->ioport),
+ BATTERY_LEN));
+ field = aml_field("DBST", AML_DWORD_ACC, AML_NOLOCK, AML_PRESERVE);
+ aml_append(field, aml_named_field("BSTA", 32));
+ aml_append(field, aml_named_field("BRTE", 32));
+ aml_append(field, aml_named_field("BCRG", 32));
+ aml_append(dev, field);
+
+ method = aml_method("_BIF", 0, AML_NOTSERIALIZED);
+ pkg = aml_package(13);
+ /* Power Unit */
+ aml_append(pkg, aml_int(0)); /* mW */
+ /* Design Capacity */
+ aml_append(pkg, aml_int(BATTERY_FULL_CAP));
+ /* Last Full Charge Capacity */
+ aml_append(pkg, aml_int(BATTERY_FULL_CAP));
+ /* Battery Technology */
+ aml_append(pkg, aml_int(1)); /* Secondary */
+ /* Design Voltage */
+ aml_append(pkg, aml_int(BATTERY_VAL_UNKNOWN));
+ /* Design Capacity of Warning */
+ aml_append(pkg, aml_int(BATTERY_CAPACITY_OF_WARNING));
+ /* Design Capacity of Low */
+ aml_append(pkg, aml_int(BATTERY_CAPACITY_OF_LOW));
+ /* Battery Capacity Granularity 1 */
+ aml_append(pkg, aml_int(BATTERY_CAPACITY_GRANULARITY));
+ /* Battery Capacity Granularity 2 */
+ aml_append(pkg, aml_int(BATTERY_CAPACITY_GRANULARITY));
+ /* Model Number */
+ aml_append(pkg, aml_string("QBAT001")); /* Model Number */
+ /* Serial Number */
+ aml_append(pkg, aml_string("SN00000")); /* Serial Number */
+ /* Battery Type */
+ aml_append(pkg, aml_string("Virtual")); /* Battery Type */
+ /* OEM Information */
+ aml_append(pkg, aml_string("QEMU")); /* OEM Information */
+ aml_append(method, aml_return(pkg));
+ aml_append(dev, method);
+
+ pkg = aml_package(4);
+ /* Battery State */
+ aml_append(pkg, aml_int(0));
+ /* Battery Present Rate */
+ aml_append(pkg, aml_int(BATTERY_VAL_UNKNOWN));
+ /* Battery Remaining Capacity */
+ aml_append(pkg, aml_int(BATTERY_VAL_UNKNOWN));
+ /* Battery Present Voltage */
+ aml_append(pkg, aml_int(BATTERY_VAL_UNKNOWN));
+ aml_append(dev, aml_name_decl("DBPR", pkg));
+
+ method = aml_method("_BST", 0, AML_NOTSERIALIZED);
+ aml_append(method, aml_store(aml_name("BSTA"), bat_state));
+ aml_append(method, aml_store(aml_name("BRTE"), bat_rate));
+ aml_append(method, aml_store(aml_name("BCRG"), bat_charge));
+ aml_append(method, aml_store(bat_state,
+ aml_index(aml_name("DBPR"), aml_int(0))));
+ aml_append(method, aml_store(bat_rate,
+ aml_index(aml_name("DBPR"), aml_int(1))));
+ aml_append(method, aml_store(bat_charge,
+ aml_index(aml_name("DBPR"), aml_int(2))));
+ aml_append(method, aml_return(aml_name("DBPR")));
+ aml_append(dev, method);
+
+ aml_append(sb_scope, dev);
+ aml_append(scope, sb_scope);
+
+ /* Device Check */
+ method = aml_method("\\_GPE._E07", 0, AML_NOTSERIALIZED);
+ aml_append(method, aml_notify(aml_name("\\_SB.BAT0"), aml_int(0x01)));
+ aml_append(scope, method);
+
+ /* Status Change */
+ method = aml_method("\\_GPE._E08", 0, AML_NOTSERIALIZED);
+ aml_append(method, aml_notify(aml_name("\\_SB.BAT0"), aml_int(0x80)));
+ aml_append(scope, method);
+
+ /* Information Change */
+ method = aml_method("\\_GPE._E09", 0, AML_NOTSERIALIZED);
+ aml_append(method, aml_notify(aml_name("\\_SB.BAT0"), aml_int(0x81)));
+ aml_append(scope, method);
+}
+
+static void battery_class_init(ObjectClass *class, const void *data)
+{
+ DeviceClass *dc = DEVICE_CLASS(class);
+ AcpiDevAmlIfClass *adevc = ACPI_DEV_AML_IF_CLASS(class);
+
+ dc->realize = battery_realize;
+ device_class_set_props(dc, battery_device_properties);
+ dc->vmsd = &battery_vmstate;
+ adevc->build_dev_aml = build_battery_aml;
+}
+
+static uint64_t battery_ioport_read(void *opaque, hwaddr addr, unsigned size)
+{
+ BatteryState *s = opaque;
+
+ battery_get_dynamic_status(s);
+
+ switch (addr) {
+ case bsta_addr0:
+ return s->state.acc[0];
+ case bsta_addr1:
+ return s->state.acc[1];
+ case bsta_addr2:
+ return s->state.acc[2];
+ case bsta_addr3:
+ return s->state.acc[3];
+ case brte_addr0:
+ return s->rate.acc[0];
+ case brte_addr1:
+ return s->rate.acc[1];
+ case brte_addr2:
+ return s->rate.acc[2];
+ case brte_addr3:
+ return s->rate.acc[3];
+ case bcrg_addr0:
+ return s->charge.acc[0];
+ case bcrg_addr1:
+ return s->charge.acc[1];
+ case bcrg_addr2:
+ return s->charge.acc[2];
+ case bcrg_addr3:
+ return s->charge.acc[3];
+ default:
+ warn_report("Battery: guest read unknown value.");
+ trace_battery_ioport_read_unknown();
+ return 0;
+ }
+}
+
+static const MemoryRegionOps battery_ops = {
+ .read = battery_ioport_read,
+ .impl = {
+ .min_access_size = 1,
+ .max_access_size = 1,
+ },
+};
+
+static void battery_instance_init(Object *obj)
+{
+ BatteryState *s = BATTERY_DEVICE(obj);
+
+ memory_region_init_io(&s->io, obj, &battery_ops, s, "battery",
+ BATTERY_LEN);
+}
+
+static const TypeInfo battery_info = {
+ .name = TYPE_BATTERY,
+ .parent = TYPE_ISA_DEVICE,
+ .instance_size = sizeof(BatteryState),
+ .class_init = battery_class_init,
+ .instance_init = battery_instance_init,
+ .interfaces = (InterfaceInfo[]) {
+ { TYPE_ACPI_DEV_AML_IF },
+ { },
+ },
+};
+
+static BatteryState *find_battery_device(void)
+{
+ Object *o = object_resolve_path_type("", TYPE_BATTERY, NULL);
+ if (!o) {
+ return NULL;
+ }
+ return BATTERY_DEVICE(o);
+}
+
+void qmp_battery_set_state(BatteryInfo *state, Error **errp)
+{
+ BatteryState *s = find_battery_device();
+
+ if (!s) {
+ error_setg(errp, "No battery device found");
+ return;
+ }
+
+ s->qmp_present = state->present;
+ s->qmp_charging = state->charging;
+ s->qmp_discharging = state->discharging;
+ s->qmp_charge_percent = state->charge_percent;
+
+ if (state->has_rate) {
+ s->qmp_rate = state->rate;
+ }
+
+ Object *obj = object_resolve_path_type("", TYPE_ACPI_DEVICE_IF, NULL);
+ if (obj) {
+ acpi_send_event(DEVICE(obj), ACPI_BATTERY_CHANGE_STATUS);
+ }
+}
+
+BatteryInfo *qmp_query_battery(Error **errp)
+{
+ BatteryState *s = find_battery_device();
+ BatteryInfo *ret;
+
+ if (!s) {
+ error_setg(errp, "No battery device found");
+ return NULL;
+ }
+
+ ret = g_new0(BatteryInfo, 1);
+
+ if (s->use_qmp_control) {
+ ret->present = s->qmp_present;
+ ret->charging = s->qmp_charging;
+ ret->discharging = s->qmp_discharging;
+ ret->charge_percent = s->qmp_charge_percent;
+ ret->has_rate = true;
+ ret->rate = s->qmp_rate;
+ } else {
+ battery_get_dynamic_status(s);
+ ret->present = true;
+ ret->charging = !!(s->state.val & BATTERY_CHARGING);
+ ret->discharging = !!(s->state.val & BATTERY_DISCHARGING);
+ ret->charge_percent = (s->charge.val * 100) / BATTERY_FULL_CAP;
+ ret->has_rate = true;
+ ret->rate = s->rate.val;
+ }
+
+ ret->has_remaining_capacity = false;
+ ret->has_design_capacity = true;
+ ret->design_capacity = BATTERY_FULL_CAP;
+
+ return ret;
+}
+
+static void battery_register_types(void)
+{
+ type_register_static(&battery_info);
+}
+
+type_init(battery_register_types)
diff --git a/hw/acpi/meson.build b/hw/acpi/meson.build
index 73f02b9691..10379a7b2c 100644
--- a/hw/acpi/meson.build
+++ b/hw/acpi/meson.build
@@ -31,6 +31,7 @@ acpi_ss.add(when: 'CONFIG_PC', if_false: files('acpi-x86-stub.c'))
if have_tpm
acpi_ss.add(files('tpm.c'))
endif
+acpi_ss.add(when: 'CONFIG_BATTERY', if_true: files('battery.c'))
system_ss.add(when: 'CONFIG_ACPI', if_false: files('acpi-stub.c', 'aml-build-stub.c', 'ghes-stub.c', 'acpi_interface.c'))
system_ss.add(when: 'CONFIG_ACPI_PCI_BRIDGE', if_false: files('pci-bridge-stub.c'))
system_ss.add_all(when: 'CONFIG_ACPI', if_true: acpi_ss)
diff --git a/hw/acpi/trace-events b/hw/acpi/trace-events
index edc93e703c..dd3e815482 100644
--- a/hw/acpi/trace-events
+++ b/hw/acpi/trace-events
@@ -87,3 +87,8 @@ acpi_nvdimm_read_io_port(void) "Alert: we never read _DSM IO Port"
acpi_nvdimm_dsm_mem_addr(uint64_t dsm_mem_addr) "dsm memory address 0x%" PRIx64
acpi_nvdimm_dsm_info(uint32_t revision, uint32_t handle, uint32_t function) "Revision 0x%" PRIx32 " Handle 0x%" PRIx32 " Function 0x%" PRIx32
acpi_nvdimm_invalid_revision(uint32_t revision) "Revision 0x%" PRIx32 " is not supported, expect 0x1"
+
+# battery.c
+battery_realize(void) "Battery device realize entry"
+battery_get_dynamic_status(uint32_t state, uint32_t rate, uint32_t charge) "Battery read state: 0x%"PRIx32", rate: %"PRIu32", charge: %"PRIu32
+battery_ioport_read_unknown(void) "Battery read unknown"
diff --git a/hw/i386/Kconfig b/hw/i386/Kconfig
index 3a0e2b8ebb..2c878fd112 100644
--- a/hw/i386/Kconfig
+++ b/hw/i386/Kconfig
@@ -39,6 +39,7 @@ config PC
imply VIRTIO_VGA
imply NVDIMM
imply FDC_ISA
+ imply BATTERY
select I8259
select I8254
select PCKBD
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 423c4959fe..790b16e582 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -1248,6 +1248,7 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
aml_append(sb_scope, dev);
}
+
aml_append(dsdt, sb_scope);
if (pm->pcihp_bridge_en || pm->pcihp_root_en) {
diff --git a/include/hw/acpi/acpi_dev_interface.h b/include/hw/acpi/acpi_dev_interface.h
index 68d9d15f50..3064ef6734 100644
--- a/include/hw/acpi/acpi_dev_interface.h
+++ b/include/hw/acpi/acpi_dev_interface.h
@@ -13,6 +13,7 @@ typedef enum {
ACPI_NVDIMM_HOTPLUG_STATUS = 16,
ACPI_VMGENID_CHANGE_STATUS = 32,
ACPI_POWER_DOWN_STATUS = 64,
+ ACPI_BATTERY_CHANGE_STATUS = 128,
} AcpiEventStatusBits;
#define TYPE_ACPI_DEVICE_IF "acpi-device-interface"
diff --git a/include/hw/acpi/battery.h b/include/hw/acpi/battery.h
new file mode 100644
index 0000000000..5c5e83abfa
--- /dev/null
+++ b/include/hw/acpi/battery.h
@@ -0,0 +1,33 @@
+/*
+ * QEMU emulated battery device.
+ *
+ * Copyright (c) 2019 Janus Technologies, Inc. (http://janustech.com)
+ *
+ * Authors:
+ * Leonid Bloch <lb.workbox@gmail.com>
+ * Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
+ * Dmitry Fleytman <dmitry.fleytman@gmail.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ */
+
+#ifndef HW_ACPI_BATTERY_H
+#define HW_ACPI_BATTERY_H
+
+#define TYPE_BATTERY "battery"
+#define BATTERY_IOPORT_PROP "ioport"
+#define BATTERY_PATH_PROP "sysfs_path"
+#define BATTERY_PROBE_STATE_INTERVAL "probe_interval"
+
+#define BATTERY_FULL_CAP 10000 /* mWh */
+
+#define BATTERY_CAPACITY_OF_WARNING (BATTERY_FULL_CAP / 10) /* 10% */
+#define BATTERY_CAPACITY_OF_LOW (BATTERY_FULL_CAP / 25) /* 4% */
+#define BATTERY_CAPACITY_GRANULARITY (BATTERY_FULL_CAP / 100) /* 1% */
+
+#define BATTERY_VAL_UNKNOWN 0xFFFFFFFF
+
+#define BATTERY_LEN 0x0C
+
+#endif
diff --git a/qapi/acpi.json b/qapi/acpi.json
index 906b3687a5..d1ad663bfd 100644
--- a/qapi/acpi.json
+++ b/qapi/acpi.json
@@ -142,3 +142,76 @@
##
{ 'event': 'ACPI_DEVICE_OST',
'data': { 'info': 'ACPIOSTInfo' } }
+
+##
+# @BatteryInfo:
+#
+# Battery state information
+#
+# @present: whether the battery is present
+#
+# @charging: whether the battery is charging
+#
+# @discharging: whether the battery is discharging
+#
+# @charge-percent: battery charge percentage (0-100)
+#
+# @rate: charge/discharge rate in mW (optional)
+#
+# @remaining-capacity: remaining capacity in mWh (optional)
+#
+# @design-capacity: design capacity in mWh (optional)
+#
+# Since: 10.2
+##
+{ 'struct': 'BatteryInfo',
+ 'data': { 'present': 'bool',
+ 'charging': 'bool',
+ 'discharging': 'bool',
+ 'charge-percent': 'int',
+ '*rate': 'int',
+ '*remaining-capacity': 'int',
+ '*design-capacity': 'int' } }
+
+##
+# @battery-set-state:
+#
+# Set the state of the emulated battery device
+#
+# @state: new battery state
+#
+
+#
+# Since: 10.2
+#
+# .. qmp-example::
+#
+# -> { "execute": "battery-set-state",
+# "arguments": { "state": { "present": true,
+# "charging": true,
+# "discharging": false,
+# "charge-percent": 85 } } }
+# <- { "return": {} }
+##
+{ 'command': 'battery-set-state',
+ 'data': { 'state': 'BatteryInfo' } }
+
+##
+# @query-battery:
+#
+# Query the current state of the emulated battery device
+#
+# Returns: current battery state
+#
+# Since: 10.2
+#
+# .. qmp-example::
+#
+# -> { "execute": "query-battery" }
+# <- { "return": { "present": true,
+# "charging": true,
+# "discharging": false,
+# "charge-percent": 85 } }
+##
+{ 'command': 'query-battery',
+ 'returns': 'BatteryInfo' }
--
2.50.1
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH v2 3/4] hw/acpi: Introduce the QEMU AC adapter
2025-08-21 17:45 [PATCH v2 0/4] Introduce a battery, AC adapter, and lid button Leonid Bloch
2025-08-21 17:45 ` [PATCH v2 1/4] hw/acpi: Increase the number of possible ACPI interrupts Leonid Bloch
2025-08-21 17:45 ` [PATCH v2 2/4] hw/acpi: Introduce the QEMU Battery Leonid Bloch
@ 2025-08-21 17:45 ` Leonid Bloch
2025-08-21 17:45 ` [PATCH v2 4/4] hw/acpi: Introduce the QEMU lid button Leonid Bloch
2025-08-21 18:03 ` [PATCH v2 0/4] Introduce a battery, AC adapter, and " Leonid Bloch
4 siblings, 0 replies; 7+ messages in thread
From: Leonid Bloch @ 2025-08-21 17:45 UTC (permalink / raw)
To: Michael S . Tsirkin, Igor Mammedov, Ani Sinha, Paolo Bonzini,
Richard Henderson, Eduardo Habkost, Eric Blake, Markus Armbruster,
Marcel Apfelbaum, Dmitry Fleytman
Cc: Leonid Bloch, qemu-devel
The AC adapter device communicates AC power state to the guest via ACPI.
It supports two modes of operation:
1. QMP control mode (default): AC adapter state is controlled
programmatically via QMP commands, ensuring deterministic behavior.
2. Host mirroring mode (optional): The device reflects the host's AC
adapter state from sysfs. Probing occurs on guest ACPI requests and
at timed intervals. State changes trigger ACPI notifications.
Properties:
- 'use-qmp': Enable QMP control mode (default: true)
- 'enable-sysfs': Enable host AC adapter mirroring (default: false)
- 'probe_interval': Probe interval in ms for sysfs mode (default: 2000)
- 'sysfs_path': Override default sysfs path /sys/class/power_supply/
The device implements the ACPI_DEV_AML_IF interface to generate its
own AML code, placing the ADP0 device directly under \_SB scope.
QMP commands:
- ac-adapter-set-state: Set AC adapter connection state
- query-ac-adapter: Query current AC adapter state
Signed-off-by: Leonid Bloch <lb.workbox@gmail.com>
---
MAINTAINERS | 6 +
docs/specs/acad.rst | 195 ++++++++++++
docs/specs/index.rst | 1 +
hw/acpi/Kconfig | 4 +
hw/acpi/acad.c | 447 +++++++++++++++++++++++++++
hw/acpi/meson.build | 1 +
hw/acpi/trace-events | 5 +
hw/i386/Kconfig | 1 +
include/hw/acpi/acad.h | 27 ++
include/hw/acpi/acpi_dev_interface.h | 1 +
qapi/acpi.json | 49 +++
11 files changed, 737 insertions(+)
create mode 100644 docs/specs/acad.rst
create mode 100644 hw/acpi/acad.c
create mode 100644 include/hw/acpi/acad.h
diff --git a/MAINTAINERS b/MAINTAINERS
index 51af9b7366..612efcb686 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2927,6 +2927,12 @@ S: Maintained
F: hw/acpi/battery.*
F: docs/specs/battery.rst
+AC Adapter
+M: Leonid Bloch <lb.workbox@gmail.com>
+S: Maintained
+F: hw/acpi/acad.*
+F: docs/specs/acad.rst
+
Subsystems
----------
Overall Audio backends
diff --git a/docs/specs/acad.rst b/docs/specs/acad.rst
new file mode 100644
index 0000000000..73d5501b8f
--- /dev/null
+++ b/docs/specs/acad.rst
@@ -0,0 +1,195 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+=================
+AC Adapter Device
+=================
+
+The AC adapter device provides AC power state information to the guest. It
+supports two operating modes:
+
+1. **QMP Control Mode** (default): AC adapter state is controlled via QMP
+ commands, providing deterministic control for testing and migration safety.
+2. **Sysfs Mode**: AC adapter state mirrors the host's physical AC adapter,
+ useful for desktop virtualization where the guest should see the host's
+ power state.
+
+Configuration
+-------------
+
+The AC adapter device is created as an ISA device using ``-device acad``.
+
+Operating Modes
+~~~~~~~~~~~~~~~
+
+**QMP Control Mode** (``use-qmp=true``, default)
+ AC adapter state is controlled via QMP commands. This mode is recommended for:
+
+ * Production environments requiring migration support
+ * Testing with predictable power states
+ * Environments without host AC adapter access
+ * Security-sensitive deployments
+
+**Sysfs Mode** (``enable-sysfs=true``)
+ AC adapter mirrors the host's physical AC adapter. This mode is useful for:
+
+ * Desktop virtualization on laptops
+ * Development and testing with real AC adapter behavior
+
+ Note: Sysfs mode reads host files and runs timers, which may impact
+ security and migration. Use with caution in production.
+
+Properties
+~~~~~~~~~~
+
+``ioport`` (default: 0x53c)
+ I/O port base address for the AC adapter device register.
+
+``use-qmp`` (default: true)
+ Enable QMP control mode. When true, AC adapter state is controlled via
+ QMP commands. Cannot be used together with ``enable-sysfs=true``.
+
+``enable-sysfs`` (default: false)
+ Enable sysfs mode to mirror the host's AC adapter. Cannot be used together
+ with ``use-qmp=true``.
+
+``probe_interval`` (default: 2000)
+ Time interval between periodic probes in milliseconds (sysfs mode only).
+ A zero value disables the periodic probes, and makes the AC adapter state
+ updates occur on guest requests only.
+
+``sysfs_path`` (default: auto-detected)
+ Path to the host's AC adapter sysfs directory (sysfs mode only). By default,
+ the device auto-detects the first AC adapter of type "Mains" in
+ ``/sys/class/power_supply/``. Use this property to specify a different
+ AC adapter, or to provide a custom path for testing purposes.
+
+Host AC Adapter Detection
+-------------------------
+
+The host's AC adapter information is taken from the sysfs AC adapter
+data, located in::
+
+ /sys/class/power_supply/[device of type "Mains"]
+
+The device automatically scans for the first AC adapter with:
+
+- A ``type`` file containing "Mains"
+- An ``online`` file that can be read
+
+If the sysfs path differs, a different AC adapter needs to be probed,
+or even if a "fake" host AC adapter is to be provided, the ``sysfs_path``
+property allows overriding the default detection.
+
+ACPI Interface
+--------------
+
+The AC adapter device is exposed to the guest as an ACPI device with:
+
+- **HID**: ``ACPI0003`` (AC Adapter)
+- **Device Path**: ``\_SB.ADP0``
+- **Notification Values**:
+
+ - ``0x80``: Status change (connected/disconnected)
+
+ACPI Methods
+~~~~~~~~~~~~
+
+``_PSR`` (Power Source)
+ Returns the current AC adapter state (0 = offline, 1 = online).
+
+``_PCL`` (Power Consumer List)
+ Returns the list of devices powered by this adapter.
+
+``_PIF`` (Power Source Information)
+ Returns static information about the power source including model number,
+ serial number, and OEM information.
+
+I/O Interface
+-------------
+
+The device uses a single I/O port register:
+
+- **Port**: ``ioport`` property value (default 0x53c)
+- **Size**: 1 byte
+- **Access**: Read-only
+
+Register Layout
+~~~~~~~~~~~~~~~
+
+**PWRS** (offset 0x00, 1 byte)
+ Current AC adapter state:
+
+ - ``0x00``: AC adapter offline (unplugged)
+ - ``0x01``: AC adapter online (plugged in)
+
+QMP Commands
+------------
+
+When using QMP control mode (default), the following commands are available:
+
+``ac-adapter-set-state``
+ Set the AC adapter connection state.
+
+ * ``connected``: Whether the AC adapter is connected (boolean)
+
+ Example::
+
+ -> { "execute": "ac-adapter-set-state",
+ "arguments": { "connected": true }}
+ <- { "return": {} }
+
+``query-ac-adapter``
+ Query the current AC adapter state.
+
+ Example::
+
+ -> { "execute": "query-ac-adapter" }
+ <- { "return": { "connected": true }}
+
+Examples
+--------
+
+QMP control mode (default - recommended)::
+
+ # Start with QMP control
+ qemu-system-x86_64 -device acad -qmp tcp:localhost:4444,server,wait=off
+
+ # From another terminal, set AC adapter state via QMP:
+ echo '{"execute":"qmp_capabilities"}
+ {"execute":"ac-adapter-set-state",
+ "arguments":{"connected":true}}' | \
+ nc -N localhost 4444
+
+Sysfs mode (mirror host AC adapter)::
+
+ # Enable sysfs mode to mirror host AC adapter
+ qemu-system-x86_64 -device acad,use-qmp=false,enable-sysfs=true
+
+ # Custom probe interval (5 seconds)
+ qemu-system-x86_64 -device acad,use-qmp=false,enable-sysfs=true,probe_interval=5000
+
+ # Specific AC adapter path
+ qemu-system-x86_64 -device acad,use-qmp=false,enable-sysfs=true,sysfs_path=/sys/class/power_supply/ADP1
+
+Testing with fake AC adapter::
+
+ # Create fake AC adapter files for testing
+ mkdir -p /tmp/fake_ac
+ echo "Mains" > /tmp/fake_ac/type
+ echo "1" > /tmp/fake_ac/online # 1 = connected, 0 = disconnected
+
+ # Use fake AC adapter in sysfs mode
+ qemu-system-x86_64 -device acad,use-qmp=false,enable-sysfs=true,sysfs_path=/tmp/fake_ac
+
+ # Update AC adapter state while VM is running (from another terminal)
+ echo "0" > /tmp/fake_ac/online # Disconnect AC adapter
+ echo "1" > /tmp/fake_ac/online # Reconnect AC adapter
+
+Combined with battery device::
+
+ # QMP mode (recommended)
+ qemu-system-x86_64 -device battery -device acad
+
+ # Sysfs mode (desktop virtualization)
+ qemu-system-x86_64 -device battery,use-qmp=false,enable-sysfs=true \
+ -device acad,use-qmp=false,enable-sysfs=true
diff --git a/docs/specs/index.rst b/docs/specs/index.rst
index 616e8228cc..e144afcd90 100644
--- a/docs/specs/index.rst
+++ b/docs/specs/index.rst
@@ -22,6 +22,7 @@ guest hardware that is specific to QEMU.
acpi_pci_hotplug
acpi_nvdimm
acpi_erst
+ acad
battery
sev-guest-firmware
fw_cfg
diff --git a/hw/acpi/Kconfig b/hw/acpi/Kconfig
index 64403378bd..9d28c3addf 100644
--- a/hw/acpi/Kconfig
+++ b/hw/acpi/Kconfig
@@ -69,6 +69,10 @@ config ACPI_VIOT
bool
depends on ACPI
+config AC_ADAPTER
+ bool
+ depends on ACPI
+
config ACPI_HW_REDUCED
bool
select ACPI
diff --git a/hw/acpi/acad.c b/hw/acpi/acad.c
new file mode 100644
index 0000000000..699198c194
--- /dev/null
+++ b/hw/acpi/acad.c
@@ -0,0 +1,447 @@
+/*
+ * QEMU emulated AC adapter device.
+ *
+ * Copyright (c) 2019 Janus Technologies, Inc. (http://janustech.com)
+ *
+ * Authors:
+ * Leonid Bloch <lb.workbox@gmail.com>
+ * Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
+ * Dmitry Fleytman <dmitry.fleytman@gmail.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "trace.h"
+#include "hw/isa/isa.h"
+#include "hw/acpi/acpi.h"
+#include "hw/nvram/fw_cfg.h"
+#include "qapi/error.h"
+#include "qemu/error-report.h"
+#include "hw/qdev-properties.h"
+#include "migration/vmstate.h"
+#include "hw/acpi/acpi_aml_interface.h"
+#include "qapi/qapi-commands-acpi.h"
+
+#include "hw/acpi/acad.h"
+
+#define AC_ADAPTER_DEVICE(obj) OBJECT_CHECK(ACADState, (obj), \
+ TYPE_AC_ADAPTER)
+
+#define AC_STA_ADDR 0
+
+#define SYSFS_PATH "/sys/class/power_supply"
+#define AC_ADAPTER_TYPE "Mains"
+#define MAX_ALLOWED_TYPE_LENGTH 16
+
+enum {
+ AC_ADAPTER_OFFLINE = 0,
+ AC_ADAPTER_ONLINE = 1,
+};
+
+typedef struct ACADState {
+ ISADevice dev;
+ MemoryRegion io;
+ uint16_t ioport;
+ uint8_t state;
+ bool use_qmp_control;
+ bool qmp_connected;
+ bool enable_sysfs;
+
+ QEMUTimer *probe_state_timer;
+ uint64_t probe_state_interval;
+
+ char *acad_path;
+} ACADState;
+
+static const char *online_file = "online";
+static const char *type_file = "type";
+
+static inline bool acad_file_accessible(char *path, const char *file)
+{
+ char full_path[PATH_MAX];
+ int path_len;
+
+ path_len = snprintf(full_path, PATH_MAX, "%s/%s", path, file);
+ if (path_len < 0 || path_len >= PATH_MAX) {
+ return false;
+ }
+
+ if (access(full_path, R_OK) == 0) {
+ return true;
+ }
+ return false;
+}
+
+static void acad_get_state(ACADState *s)
+{
+ char file_path[PATH_MAX];
+ int path_len;
+ uint8_t val;
+ FILE *ff;
+
+ path_len = snprintf(file_path, PATH_MAX, "%s/%s", s->acad_path,
+ online_file);
+ if (path_len < 0 || path_len >= PATH_MAX) {
+ warn_report("Could not read the AC adapter state.");
+ return;
+ }
+
+ ff = fopen(file_path, "r");
+ if (ff == NULL) {
+ warn_report("Could not read the AC adapter state.");
+ return;
+ }
+
+ if (!fscanf(ff, "%hhu", &val)) {
+ warn_report("AC adapter state unreadable.");
+ } else {
+ switch (val) {
+ case AC_ADAPTER_OFFLINE:
+ case AC_ADAPTER_ONLINE:
+ s->state = val;
+ break;
+ default:
+ warn_report("AC adapter state undetermined.");
+ }
+ }
+ fclose(ff);
+}
+
+static void acad_get_dynamic_status(ACADState *s)
+{
+ if (s->use_qmp_control) {
+ s->state = s->qmp_connected ? AC_ADAPTER_ONLINE : AC_ADAPTER_OFFLINE;
+ } else if (s->enable_sysfs) {
+ acad_get_state(s);
+ } else {
+ s->state = AC_ADAPTER_OFFLINE;
+ }
+
+ trace_acad_get_dynamic_status(s->state);
+}
+
+static void acad_probe_state(void *opaque)
+{
+ ACADState *s = opaque;
+
+ uint8_t state_before = s->state;
+
+ acad_get_dynamic_status(s);
+
+ if (state_before != s->state) {
+ Object *obj = object_resolve_path_type("", TYPE_ACPI_DEVICE_IF, NULL);
+ acpi_send_event(DEVICE(obj), ACPI_AC_ADAPTER_CHANGE_STATUS);
+ }
+ timer_mod(s->probe_state_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
+ s->probe_state_interval);
+}
+
+static void acad_probe_state_timer_init(ACADState *s)
+{
+ if (s->enable_sysfs && s->probe_state_interval > 0) {
+ s->probe_state_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL,
+ acad_probe_state, s);
+ timer_mod(s->probe_state_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
+ s->probe_state_interval);
+ }
+}
+
+static bool acad_verify_sysfs(ACADState *s, char *path)
+{
+ FILE *ff;
+ char type_path[PATH_MAX];
+ int path_len;
+ char val[MAX_ALLOWED_TYPE_LENGTH];
+
+ path_len = snprintf(type_path, PATH_MAX, "%s/%s", path, type_file);
+ if (path_len < 0 || path_len >= PATH_MAX) {
+ return false;
+ }
+
+ ff = fopen(type_path, "r");
+ if (ff == NULL) {
+ return false;
+ }
+
+ if (fgets(val, MAX_ALLOWED_TYPE_LENGTH, ff) == NULL) {
+ fclose(ff);
+ return false;
+ } else {
+ val[strcspn(val, "\n")] = 0;
+ if (strncmp(val, AC_ADAPTER_TYPE, MAX_ALLOWED_TYPE_LENGTH)) {
+ fclose(ff);
+ return false;
+ }
+ }
+ fclose(ff);
+
+ return acad_file_accessible(path, online_file);
+}
+
+static bool get_acad_path(DeviceState *dev)
+{
+ ACADState *s = AC_ADAPTER_DEVICE(dev);
+ DIR *dir;
+ struct dirent *ent;
+ char bp[PATH_MAX];
+ int path_len;
+
+ if (s->acad_path) {
+ return acad_verify_sysfs(s, s->acad_path);
+ }
+
+ dir = opendir(SYSFS_PATH);
+ if (dir == NULL) {
+ return false;
+ }
+
+ ent = readdir(dir);
+ while (ent != NULL) {
+ if (ent->d_name[0] != '.') {
+ path_len = snprintf(bp, PATH_MAX, "%s/%s", SYSFS_PATH,
+ ent->d_name);
+ if (path_len < 0 || path_len >= PATH_MAX) {
+ return false;
+ }
+ if (acad_verify_sysfs(s, bp)) {
+ qdev_prop_set_string(dev, AC_ADAPTER_PATH_PROP, bp);
+ closedir(dir);
+ return true;
+ }
+ }
+ ent = readdir(dir);
+ }
+ closedir(dir);
+
+ return false;
+}
+
+static void acad_realize(DeviceState *dev, Error **errp)
+{
+ ISADevice *d = ISA_DEVICE(dev);
+ ACADState *s = AC_ADAPTER_DEVICE(dev);
+ FWCfgState *fw_cfg = fw_cfg_find();
+ uint16_t *acad_port;
+ char err_details[32] = {};
+
+ trace_acad_realize();
+
+ if (s->use_qmp_control && s->enable_sysfs) {
+ error_setg(errp, "Cannot enable both QMP control and sysfs mode");
+ return;
+ }
+
+ if (s->enable_sysfs) {
+ if (!s->acad_path) {
+ strcpy(err_details, " Try using 'sysfs_path='");
+ }
+
+ if (!get_acad_path(dev)) {
+ error_setg(errp, "AC adapter sysfs path not found or unreadable.%s",
+ err_details);
+ return;
+ }
+ }
+
+ isa_register_ioport(d, &s->io, s->ioport);
+
+ acad_probe_state_timer_init(s);
+
+ if (!fw_cfg) {
+ return;
+ }
+
+ acad_port = g_malloc(sizeof(*acad_port));
+ *acad_port = cpu_to_le16(s->ioport);
+ fw_cfg_add_file(fw_cfg, "etc/acad-port", acad_port,
+ sizeof(*acad_port));
+}
+
+static const Property acad_device_properties[] = {
+ DEFINE_PROP_UINT16(AC_ADAPTER_IOPORT_PROP, ACADState, ioport, 0x53c),
+ DEFINE_PROP_BOOL("use-qmp", ACADState, use_qmp_control, true),
+ DEFINE_PROP_BOOL("enable-sysfs", ACADState, enable_sysfs, false),
+ DEFINE_PROP_UINT64(AC_ADAPTER_PROBE_STATE_INTERVAL, ACADState,
+ probe_state_interval, 2000),
+ DEFINE_PROP_STRING(AC_ADAPTER_PATH_PROP, ACADState, acad_path),
+};
+
+static const VMStateDescription acad_vmstate = {
+ .name = "acad",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .fields = (VMStateField[]) {
+ VMSTATE_UINT16(ioport, ACADState),
+ VMSTATE_UINT64(probe_state_interval, ACADState),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+static void build_acad_aml(AcpiDevAmlIf *adev, Aml *scope)
+{
+ Aml *dev, *field, *method, *pkg;
+ Aml *acad_state;
+ Aml *sb_scope;
+ ACADState *s = AC_ADAPTER_DEVICE(adev);
+
+ acad_state = aml_local(0);
+
+ sb_scope = aml_scope("\\_SB");
+ dev = aml_device("ADP0");
+ aml_append(dev, aml_name_decl("_HID", aml_string("ACPI0003")));
+
+ aml_append(dev, aml_operation_region("ACST", AML_SYSTEM_IO,
+ aml_int(s->ioport),
+ AC_ADAPTER_LEN));
+ field = aml_field("ACST", AML_BYTE_ACC, AML_NOLOCK, AML_PRESERVE);
+ aml_append(field, aml_named_field("PWRS", 8));
+ aml_append(dev, field);
+
+ method = aml_method("_PSR", 0, AML_NOTSERIALIZED);
+ aml_append(method, aml_store(aml_name("PWRS"), acad_state));
+ aml_append(method, aml_return(acad_state));
+ aml_append(dev, method);
+
+ method = aml_method("_PCL", 0, AML_NOTSERIALIZED);
+ pkg = aml_package(1);
+ aml_append(pkg, aml_name("_SB"));
+ aml_append(method, aml_return(pkg));
+ aml_append(dev, method);
+
+ method = aml_method("_PIF", 0, AML_NOTSERIALIZED);
+ pkg = aml_package(6);
+ /* Power Source State */
+ aml_append(pkg, aml_int(0)); /* Non-redundant, non-shared */
+ /* Maximum Output Power */
+ aml_append(pkg, aml_int(AC_ADAPTER_VAL_UNKNOWN));
+ /* Maximum Input Power */
+ aml_append(pkg, aml_int(AC_ADAPTER_VAL_UNKNOWN));
+ /* Model Number */
+ aml_append(pkg, aml_string("QADP001"));
+ /* Serial Number */
+ aml_append(pkg, aml_string("SN00000"));
+ /* OEM Information */
+ aml_append(pkg, aml_string("QEMU"));
+ aml_append(method, aml_return(pkg));
+ aml_append(dev, method);
+
+ aml_append(sb_scope, dev);
+ aml_append(scope, sb_scope);
+
+ /* Status Change */
+ method = aml_method("\\_GPE._E0A", 0, AML_NOTSERIALIZED);
+ aml_append(method, aml_notify(aml_name("\\_SB.ADP0"), aml_int(0x80)));
+ aml_append(scope, method);
+}
+
+static void acad_class_init(ObjectClass *class, const void *data)
+{
+ DeviceClass *dc = DEVICE_CLASS(class);
+ AcpiDevAmlIfClass *adevc = ACPI_DEV_AML_IF_CLASS(class);
+
+ dc->realize = acad_realize;
+ device_class_set_props(dc, acad_device_properties);
+ dc->vmsd = &acad_vmstate;
+ adevc->build_dev_aml = build_acad_aml;
+}
+
+static uint64_t acad_ioport_read(void *opaque, hwaddr addr, unsigned size)
+{
+ ACADState *s = opaque;
+
+ acad_get_dynamic_status(s);
+
+ switch (addr) {
+ case AC_STA_ADDR:
+ return s->state;
+ default:
+ warn_report("AC adapter: guest read unknown value.");
+ trace_acad_ioport_read_unknown();
+ return 0;
+ }
+}
+
+static const MemoryRegionOps acad_ops = {
+ .read = acad_ioport_read,
+ .impl = {
+ .min_access_size = 1,
+ .max_access_size = 1,
+ },
+};
+
+static void acad_instance_init(Object *obj)
+{
+ ACADState *s = AC_ADAPTER_DEVICE(obj);
+
+ memory_region_init_io(&s->io, obj, &acad_ops, s, "acad",
+ AC_ADAPTER_LEN);
+}
+
+static const TypeInfo acad_info = {
+ .name = TYPE_AC_ADAPTER,
+ .parent = TYPE_ISA_DEVICE,
+ .instance_size = sizeof(ACADState),
+ .class_init = acad_class_init,
+ .instance_init = acad_instance_init,
+ .interfaces = (InterfaceInfo[]) {
+ { TYPE_ACPI_DEV_AML_IF },
+ { },
+ },
+};
+
+static ACADState *find_acad_device(void)
+{
+ Object *o = object_resolve_path_type("", TYPE_AC_ADAPTER, NULL);
+ if (!o) {
+ return NULL;
+ }
+ return AC_ADAPTER_DEVICE(o);
+}
+
+void qmp_ac_adapter_set_state(bool connected, Error **errp)
+{
+ ACADState *s = find_acad_device();
+
+ if (!s) {
+ error_setg(errp, "No AC adapter device found");
+ return;
+ }
+
+ s->qmp_connected = connected;
+
+ Object *obj = object_resolve_path_type("", TYPE_ACPI_DEVICE_IF, NULL);
+ if (obj) {
+ acpi_send_event(DEVICE(obj), ACPI_AC_ADAPTER_CHANGE_STATUS);
+ }
+}
+
+AcAdapterInfo *qmp_query_ac_adapter(Error **errp)
+{
+ ACADState *s = find_acad_device();
+ AcAdapterInfo *ret;
+
+ if (!s) {
+ error_setg(errp, "No AC adapter device found");
+ return NULL;
+ }
+
+ ret = g_new0(AcAdapterInfo, 1);
+
+ if (s->use_qmp_control) {
+ ret->connected = s->qmp_connected;
+ } else {
+ acad_get_dynamic_status(s);
+ ret->connected = (s->state == AC_ADAPTER_ONLINE);
+ }
+
+ return ret;
+}
+
+static void acad_register_types(void)
+{
+ type_register_static(&acad_info);
+}
+
+type_init(acad_register_types)
diff --git a/hw/acpi/meson.build b/hw/acpi/meson.build
index 10379a7b2c..2b24951f28 100644
--- a/hw/acpi/meson.build
+++ b/hw/acpi/meson.build
@@ -32,6 +32,7 @@ if have_tpm
acpi_ss.add(files('tpm.c'))
endif
acpi_ss.add(when: 'CONFIG_BATTERY', if_true: files('battery.c'))
+acpi_ss.add(when: 'CONFIG_AC_ADAPTER', if_true: files('acad.c'))
system_ss.add(when: 'CONFIG_ACPI', if_false: files('acpi-stub.c', 'aml-build-stub.c', 'ghes-stub.c', 'acpi_interface.c'))
system_ss.add(when: 'CONFIG_ACPI_PCI_BRIDGE', if_false: files('pci-bridge-stub.c'))
system_ss.add_all(when: 'CONFIG_ACPI', if_true: acpi_ss)
diff --git a/hw/acpi/trace-events b/hw/acpi/trace-events
index dd3e815482..68ac6e9701 100644
--- a/hw/acpi/trace-events
+++ b/hw/acpi/trace-events
@@ -92,3 +92,8 @@ acpi_nvdimm_invalid_revision(uint32_t revision) "Revision 0x%" PRIx32 " is not s
battery_realize(void) "Battery device realize entry"
battery_get_dynamic_status(uint32_t state, uint32_t rate, uint32_t charge) "Battery read state: 0x%"PRIx32", rate: %"PRIu32", charge: %"PRIu32
battery_ioport_read_unknown(void) "Battery read unknown"
+
+# acad.c
+acad_realize(void) "AC adapter device realize entry"
+acad_get_dynamic_status(uint8_t state) "AC adapter read state: %"PRIu8
+acad_ioport_read_unknown(void) "AC adapter read unknown"
diff --git a/hw/i386/Kconfig b/hw/i386/Kconfig
index 2c878fd112..baab382a2e 100644
--- a/hw/i386/Kconfig
+++ b/hw/i386/Kconfig
@@ -40,6 +40,7 @@ config PC
imply NVDIMM
imply FDC_ISA
imply BATTERY
+ imply AC_ADAPTER
select I8259
select I8254
select PCKBD
diff --git a/include/hw/acpi/acad.h b/include/hw/acpi/acad.h
new file mode 100644
index 0000000000..a4e7149488
--- /dev/null
+++ b/include/hw/acpi/acad.h
@@ -0,0 +1,27 @@
+/*
+ * QEMU emulated AC adapter device.
+ *
+ * Copyright (c) 2019 Janus Technologies, Inc. (http://janustech.com)
+ *
+ * Authors:
+ * Leonid Bloch <lb.workbox@gmail.com>
+ * Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
+ * Dmitry Fleytman <dmitry.fleytman@gmail.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ */
+
+#ifndef HW_ACPI_AC_ADAPTER_H
+#define HW_ACPI_AC_ADAPTER_H
+
+#define TYPE_AC_ADAPTER "acad"
+#define AC_ADAPTER_IOPORT_PROP "ioport"
+#define AC_ADAPTER_PATH_PROP "sysfs_path"
+#define AC_ADAPTER_PROBE_STATE_INTERVAL "probe_interval"
+
+#define AC_ADAPTER_VAL_UNKNOWN 0xFFFFFFFF
+
+#define AC_ADAPTER_LEN 1
+
+#endif
diff --git a/include/hw/acpi/acpi_dev_interface.h b/include/hw/acpi/acpi_dev_interface.h
index 3064ef6734..588fbbd05f 100644
--- a/include/hw/acpi/acpi_dev_interface.h
+++ b/include/hw/acpi/acpi_dev_interface.h
@@ -14,6 +14,7 @@ typedef enum {
ACPI_VMGENID_CHANGE_STATUS = 32,
ACPI_POWER_DOWN_STATUS = 64,
ACPI_BATTERY_CHANGE_STATUS = 128,
+ ACPI_AC_ADAPTER_CHANGE_STATUS = 1024,
} AcpiEventStatusBits;
#define TYPE_ACPI_DEVICE_IF "acpi-device-interface"
diff --git a/qapi/acpi.json b/qapi/acpi.json
index d1ad663bfd..52e151f0e6 100644
--- a/qapi/acpi.json
+++ b/qapi/acpi.json
@@ -215,3 +215,52 @@
##
{ 'command': 'query-battery',
'returns': 'BatteryInfo' }
+
+##
+# @ac-adapter-set-state:
+#
+# Set the state of the emulated AC adapter device
+#
+# @connected: whether the AC adapter is connected
+#
+
+#
+# Since: 10.2
+#
+# .. qmp-example::
+#
+# -> { "execute": "ac-adapter-set-state",
+# "arguments": { "connected": true } }
+# <- { "return": {} }
+##
+{ 'command': 'ac-adapter-set-state',
+ 'data': { 'connected': 'bool' } }
+
+##
+# @AcAdapterInfo:
+#
+# AC adapter state information
+#
+# @connected: whether the AC adapter is connected
+#
+# Since: 10.2
+##
+{ 'struct': 'AcAdapterInfo',
+ 'data': { 'connected': 'bool' } }
+
+##
+# @query-ac-adapter:
+#
+# Query the current state of the emulated AC adapter device
+#
+# Returns: AC adapter connection state
+#
+# Since: 10.2
+#
+# .. qmp-example::
+#
+# -> { "execute": "query-ac-adapter" }
+# <- { "return": { "connected": true } }
+##
+{ 'command': 'query-ac-adapter',
+ 'returns': 'AcAdapterInfo' }
--
2.50.1
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH v2 4/4] hw/acpi: Introduce the QEMU lid button
2025-08-21 17:45 [PATCH v2 0/4] Introduce a battery, AC adapter, and lid button Leonid Bloch
` (2 preceding siblings ...)
2025-08-21 17:45 ` [PATCH v2 3/4] hw/acpi: Introduce the QEMU AC adapter Leonid Bloch
@ 2025-08-21 17:45 ` Leonid Bloch
2025-08-21 18:03 ` [PATCH v2 0/4] Introduce a battery, AC adapter, and " Leonid Bloch
4 siblings, 0 replies; 7+ messages in thread
From: Leonid Bloch @ 2025-08-21 17:45 UTC (permalink / raw)
To: Michael S . Tsirkin, Igor Mammedov, Ani Sinha, Paolo Bonzini,
Richard Henderson, Eduardo Habkost, Eric Blake, Markus Armbruster,
Marcel Apfelbaum, Dmitry Fleytman
Cc: Leonid Bloch, qemu-devel
The lid button device communicates laptop lid state to the guest via ACPI.
It supports two modes of operation:
1. QMP control mode (default): Lid state is controlled programmatically
via QMP commands for consistent behavior across environments.
2. Host mirroring mode (optional): The device reflects the host's lid
button state from procfs (/proc/acpi/button/lid/*/state). State
changes trigger ACPI notifications to the guest.
Properties:
- 'use-qmp': Enable QMP control mode (default: true)
- 'enable-procfs': Enable host lid button mirroring (default: false)
- 'probe_interval': Probe interval in ms for procfs mode (default: 2000)
- 'procfs_path': Override default procfs path /proc/acpi/button
The device implements the ACPI_DEV_AML_IF interface to generate its
own AML code, placing the LID0 device directly under \_SB scope.
QMP commands:
- lid-button-set-state: Set lid open/closed state
- query-lid-button: Query current lid state
Signed-off-by: Leonid Bloch <lb.workbox@gmail.com>
---
MAINTAINERS | 6 +
docs/specs/button.rst | 189 ++++++++++++
docs/specs/index.rst | 1 +
hw/acpi/Kconfig | 4 +
hw/acpi/button.c | 438 +++++++++++++++++++++++++++
hw/acpi/meson.build | 1 +
hw/acpi/trace-events | 5 +
hw/i386/Kconfig | 1 +
include/hw/acpi/acpi_dev_interface.h | 1 +
include/hw/acpi/button.h | 25 ++
qapi/acpi.json | 49 +++
11 files changed, 720 insertions(+)
create mode 100644 docs/specs/button.rst
create mode 100644 hw/acpi/button.c
create mode 100644 include/hw/acpi/button.h
diff --git a/MAINTAINERS b/MAINTAINERS
index 612efcb686..4d54a2ffb5 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2933,6 +2933,12 @@ S: Maintained
F: hw/acpi/acad.*
F: docs/specs/acad.rst
+Button
+M: Leonid Bloch <lb.workbox@gmail.com>
+S: Maintained
+F: hw/acpi/button.*
+F: docs/specs/button.rst
+
Subsystems
----------
Overall Audio backends
diff --git a/docs/specs/button.rst b/docs/specs/button.rst
new file mode 100644
index 0000000000..10a940b9f5
--- /dev/null
+++ b/docs/specs/button.rst
@@ -0,0 +1,189 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+========================
+Laptop Lid Button Device
+========================
+
+The button device provides laptop lid button state information to the guest.
+It supports two operating modes:
+
+1. **QMP Control Mode** (default): Lid state is controlled via QMP commands,
+ providing deterministic control for testing and migration safety.
+2. **Procfs Mode**: Lid state mirrors the host's physical lid button, useful
+ for desktop virtualization where the guest should see the host's lid state.
+
+Configuration
+-------------
+
+The lid button device is created as an ISA device using ``-device button``.
+
+Operating Modes
+~~~~~~~~~~~~~~~
+
+**QMP Control Mode** (``use-qmp=true``, default)
+ Lid state is controlled via QMP commands. This mode is recommended for:
+
+ * Production environments requiring migration support
+ * Testing with predictable lid states
+ * Environments without host lid button access
+ * Security-sensitive deployments
+
+**Procfs Mode** (``enable-procfs=true``)
+ Lid mirrors the host's physical lid button. This mode is useful for:
+
+ * Desktop virtualization on laptops
+ * Development and testing with real lid button behavior
+
+ Note: Procfs mode reads host files and runs timers, which may impact
+ security and migration. Use with caution in production.
+
+Properties
+~~~~~~~~~~
+
+``ioport`` (default: 0x53d)
+ I/O port base address for the lid button device register.
+
+``use-qmp`` (default: true)
+ Enable QMP control mode. When true, lid state is controlled via
+ QMP commands. Cannot be used together with ``enable-procfs=true``.
+
+``enable-procfs`` (default: false)
+ Enable procfs mode to mirror the host's lid button. Cannot be used together
+ with ``use-qmp=true``.
+
+``probe_interval`` (default: 2000)
+ Time interval between periodic probes in milliseconds (procfs mode only).
+ The minimum allowed value is 10ms to prevent excessive polling.
+
+``procfs_path`` (default: /proc/acpi/button)
+ Path to the host's lid button procfs directory (procfs mode only). The device
+ will automatically scan this directory to find the lid state file. Use this
+ property to specify a different path or to provide a custom location for
+ testing purposes.
+
+Host Lid Button Detection
+-------------------------
+
+The host's lid button information is taken from::
+
+ /proc/acpi/button/lid/*/state
+
+This file is expected to be formatted as:
+
+- ``state: open`` (if the lid is open)
+- ``state: closed`` (if the lid is closed)
+
+These formats are based on the Linux 'button' driver.
+
+The device automatically scans the ``/proc/acpi/button/lid/`` directory
+for subdirectories containing a readable ``state`` file. If the procfs path
+differs, a different lid button needs to be probed, or even if a "fake" host
+lid button is to be provided, the ``procfs_path`` property allows overriding
+the default detection.
+
+ACPI Interface
+--------------
+
+The lid button device is exposed to the guest as an ACPI device with:
+
+- **HID**: ``PNP0C0D`` (Lid Device)
+- **Device Path**: ``\_SB.LID0``
+- **Notification Values**:
+
+ - ``0x80``: Status change (lid opened/closed)
+
+ACPI Methods
+~~~~~~~~~~~~
+
+``_LID`` (Lid Status)
+ Returns the current lid state (0 = closed, 1 = open).
+
+I/O Interface
+-------------
+
+The device uses a single I/O port register:
+
+- **Port**: ``ioport`` property value (default 0x53d)
+- **Size**: 1 byte
+- **Access**: Read-only
+
+Register Layout
+~~~~~~~~~~~~~~~
+
+**LIDS** (offset 0x00, 1 byte)
+ Current lid state:
+
+ - ``0x00``: Lid closed
+ - ``0x01``: Lid open
+
+QMP Commands
+------------
+
+When using QMP control mode (default), the following commands are available:
+
+``lid-button-set-state``
+ Set the lid button state.
+
+ * ``open``: Whether the lid is open (boolean)
+
+ Example::
+
+ -> { "execute": "lid-button-set-state",
+ "arguments": { "open": true }}
+ <- { "return": {} }
+
+``query-lid-button``
+ Query the current lid button state.
+
+ Example::
+
+ -> { "execute": "query-lid-button" }
+ <- { "return": { "open": true }}
+
+Examples
+--------
+
+QMP control mode (default - recommended)::
+
+ # Start with QMP control
+ qemu-system-x86_64 -device button -qmp tcp:localhost:4444,server,wait=off
+
+ # From another terminal, set lid state via QMP:
+ echo '{"execute":"qmp_capabilities"}
+ {"execute":"lid-button-set-state",
+ "arguments":{"open":false}}' | \
+ nc -N localhost 4444
+
+Procfs mode (mirror host lid button)::
+
+ # Enable procfs mode to mirror host lid button
+ qemu-system-x86_64 -device button,use-qmp=false,enable-procfs=true
+
+ # Custom probe interval (5 seconds)
+ qemu-system-x86_64 -device button,use-qmp=false,enable-procfs=true,probe_interval=5000
+
+ # Custom procfs path
+ qemu-system-x86_64 -device button,use-qmp=false,enable-procfs=true,procfs_path=/custom/path
+
+Testing with fake lid button::
+
+ # Create fake lid button files for testing
+ mkdir -p /tmp/fake_lid/lid/LID0
+ echo "state: open" > /tmp/fake_lid/lid/LID0/state # Format: "state: open" or "state: closed"
+
+ # Use fake lid button in procfs mode
+ qemu-system-x86_64 -device button,use-qmp=false,enable-procfs=true,procfs_path=/tmp/fake_lid
+
+ # Update lid state while VM is running (from another terminal)
+ echo "state: closed" > /tmp/fake_lid/lid/LID0/state # Close lid
+ echo "state: open" > /tmp/fake_lid/lid/LID0/state # Open lid
+
+Combined with other laptop devices::
+
+ # QMP mode (recommended)
+ qemu-system-x86_64 -device battery -device acad -device button
+
+ # Procfs/sysfs mode (desktop virtualization)
+ qemu-system-x86_64 -device battery,use-qmp=false,enable-sysfs=true \
+ -device acad,use-qmp=false,enable-sysfs=true \
+ -device button,use-qmp=false,enable-procfs=true
diff --git a/docs/specs/index.rst b/docs/specs/index.rst
index e144afcd90..e1c9b91b7b 100644
--- a/docs/specs/index.rst
+++ b/docs/specs/index.rst
@@ -24,6 +24,7 @@ guest hardware that is specific to QEMU.
acpi_erst
acad
battery
+ button
sev-guest-firmware
fw_cfg
fsi
diff --git a/hw/acpi/Kconfig b/hw/acpi/Kconfig
index 9d28c3addf..6600685855 100644
--- a/hw/acpi/Kconfig
+++ b/hw/acpi/Kconfig
@@ -73,6 +73,10 @@ config AC_ADAPTER
bool
depends on ACPI
+config BUTTON
+ bool
+ depends on ACPI
+
config ACPI_HW_REDUCED
bool
select ACPI
diff --git a/hw/acpi/button.c b/hw/acpi/button.c
new file mode 100644
index 0000000000..dfe86af713
--- /dev/null
+++ b/hw/acpi/button.c
@@ -0,0 +1,438 @@
+/*
+ * QEMU emulated lid button device
+ *
+ * Copyright (c) 2019 Janus Technologies, Inc. (http://janustech.com)
+ *
+ * Authors:
+ * Leonid Bloch <lb.workbox@gmail.com>
+ * Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
+ * Dmitry Fleytman <dmitry.fleytman@gmail.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "trace.h"
+#include "hw/isa/isa.h"
+#include "hw/acpi/acpi.h"
+#include "hw/nvram/fw_cfg.h"
+#include "qapi/error.h"
+#include "qemu/error-report.h"
+#include "hw/qdev-properties.h"
+#include "migration/vmstate.h"
+#include "hw/acpi/acpi_aml_interface.h"
+#include "qapi/qapi-commands-acpi.h"
+
+#include "hw/acpi/button.h"
+
+#define BUTTON_DEVICE(obj) OBJECT_CHECK(BUTTONState, (obj), \
+ TYPE_BUTTON)
+
+#define BUTTON_STA_ADDR 0
+
+#define PROCFS_PATH "/proc/acpi/button"
+#define LID_DIR "lid"
+#define LID_STATE_FILE "state"
+#define MIN_BUTTON_PROBE_INTERVAL 10 /* ms */
+#define MAX_ALLOWED_LINE_LENGTH 32 /* For convenience when comparing */
+
+enum {
+ LID_CLOSED = 0,
+ LID_OPEN = 1,
+};
+
+static const char *lid_state[] = { "closed", "open" };
+
+typedef struct BUTTONState {
+ ISADevice dev;
+ MemoryRegion io;
+ uint16_t ioport;
+ uint8_t lid_state;
+ bool use_qmp_control;
+ bool qmp_lid_open;
+ bool enable_procfs;
+
+ QEMUTimer *probe_state_timer;
+ uint64_t probe_state_interval;
+
+ char *button_path;
+ char lid_dir[MAX_ALLOWED_LINE_LENGTH];
+} BUTTONState;
+
+static inline bool button_file_accessible(char *path, const char *dir,
+ char *subdir, const char *file)
+{
+ char full_path[PATH_MAX];
+ int path_len;
+
+ path_len = snprintf(full_path, PATH_MAX, "%s/%s/%s/%s", path, dir, subdir,
+ file);
+ if (path_len < 0 || path_len >= PATH_MAX) {
+ return false;
+ }
+
+ if (access(full_path, R_OK) == 0) {
+ return true;
+ }
+ return false;
+}
+
+static void button_get_lid_state(BUTTONState *s)
+{
+ char file_path[PATH_MAX];
+ int path_len;
+ char line[MAX_ALLOWED_LINE_LENGTH];
+ FILE *ff;
+
+ path_len = snprintf(file_path, PATH_MAX, "%s/%s/%s/%s", s->button_path,
+ LID_DIR, s->lid_dir, LID_STATE_FILE);
+ if (path_len < 0 || path_len >= PATH_MAX) {
+ warn_report("Could not read the lid state.");
+ return;
+ }
+
+ ff = fopen(file_path, "r");
+ if (ff == NULL) {
+ warn_report("Could not read the lid state.");
+ return;
+ }
+
+ if (fgets(line, MAX_ALLOWED_LINE_LENGTH, ff) == NULL) {
+ warn_report("Lid state unreadable.");
+ } else {
+ if (strstr(line, lid_state[LID_OPEN]) != NULL) {
+ s->lid_state = LID_OPEN;
+ } else if (strstr(line, lid_state[LID_CLOSED]) != NULL) {
+ s->lid_state = LID_CLOSED;
+ } else {
+ warn_report("Lid state undetermined.");
+ }
+ }
+
+ fclose(ff);
+}
+
+static void button_get_dynamic_status(BUTTONState *s)
+{
+ trace_button_get_dynamic_status();
+
+ if (s->use_qmp_control) {
+ s->lid_state = s->qmp_lid_open ? LID_OPEN : LID_CLOSED;
+ } else if (s->enable_procfs) {
+ button_get_lid_state(s);
+ } else {
+ s->lid_state = LID_CLOSED;
+ }
+}
+
+static void button_probe_state(void *opaque)
+{
+ BUTTONState *s = opaque;
+
+ uint8_t lid_state_before = s->lid_state;
+
+ button_get_dynamic_status(s);
+
+ if (lid_state_before != s->lid_state) {
+ Object *obj = object_resolve_path_type("", TYPE_ACPI_DEVICE_IF, NULL);
+ acpi_send_event(DEVICE(obj), ACPI_BUTTON_CHANGE_STATUS);
+ }
+ timer_mod(s->probe_state_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
+ s->probe_state_interval);
+}
+
+static void button_probe_state_timer_init(BUTTONState *s)
+{
+ if (s->enable_procfs && s->probe_state_interval > 0) {
+ s->probe_state_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL,
+ button_probe_state, s);
+ timer_mod(s->probe_state_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
+ s->probe_state_interval);
+ }
+}
+
+static inline bool button_verify_lid_procfs(char *path, char *lid_subdir)
+{
+ return button_file_accessible(path, LID_DIR, lid_subdir, LID_STATE_FILE);
+}
+
+static bool button_get_lid_dir(BUTTONState *s, char *path)
+{
+ DIR *dir;
+ char lid_path[PATH_MAX];
+ int path_len;
+ struct dirent *ent;
+
+ path_len = snprintf(lid_path, PATH_MAX, "%s/%s", path, LID_DIR);
+ if (path_len < 0 || path_len >= PATH_MAX) {
+ return false;
+ }
+
+ dir = opendir(lid_path);
+ if (dir == NULL) {
+ return false;
+ }
+
+ ent = readdir(dir);
+ while (ent != NULL) {
+ if (ent->d_name[0] != '.') {
+ if (button_verify_lid_procfs(path, ent->d_name)) {
+ path_len = snprintf(s->lid_dir, strlen(ent->d_name) + 1, "%s",
+ ent->d_name);
+ if (path_len < 0 || path_len > strlen(ent->d_name)) {
+ return false;
+ }
+ closedir(dir);
+ return true;
+ }
+ }
+ ent = readdir(dir);
+ }
+ closedir(dir);
+ return false;
+}
+
+static bool get_button_path(DeviceState *dev)
+{
+ BUTTONState *s = BUTTON_DEVICE(dev);
+ char procfs_path[PATH_MAX];
+ int path_len;
+
+ if (s->button_path) {
+ path_len = snprintf(procfs_path, strlen(s->button_path) + 1, "%s",
+ s->button_path);
+ if (path_len < 0 || path_len > strlen(s->button_path)) {
+ return false;
+ }
+ } else {
+ path_len = snprintf(procfs_path, sizeof(PROCFS_PATH), "%s",
+ PROCFS_PATH);
+ if (path_len < 0 || path_len >= sizeof(PROCFS_PATH)) {
+ return false;
+ }
+ }
+
+ if (button_get_lid_dir(s, procfs_path)) {
+ qdev_prop_set_string(dev, BUTTON_PATH_PROP, procfs_path);
+ return true;
+ }
+
+ return false;
+}
+
+static void button_realize(DeviceState *dev, Error **errp)
+{
+ ISADevice *d = ISA_DEVICE(dev);
+ BUTTONState *s = BUTTON_DEVICE(dev);
+ FWCfgState *fw_cfg = fw_cfg_find();
+ uint16_t *button_port;
+ char err_details[32] = {};
+
+ trace_button_realize();
+
+ if (s->use_qmp_control && s->enable_procfs) {
+ error_setg(errp, "Cannot enable both QMP control and procfs mode");
+ return;
+ }
+
+ /* Initialize lid to open by default when in QMP mode */
+ if (s->use_qmp_control) {
+ s->qmp_lid_open = true;
+ }
+
+ if (s->probe_state_interval < MIN_BUTTON_PROBE_INTERVAL) {
+ error_setg(errp, "'probe_state_interval' must be greater than %d ms",
+ MIN_BUTTON_PROBE_INTERVAL);
+ return;
+ }
+
+ if (s->enable_procfs) {
+ if (!s->button_path) {
+ strcpy(err_details, " Try using 'procfs_path='");
+ }
+
+ if (!get_button_path(dev)) {
+ error_setg(errp, "Button procfs path not found or unreadable.%s",
+ err_details);
+ return;
+ }
+ }
+
+ isa_register_ioport(d, &s->io, s->ioport);
+
+ button_probe_state_timer_init(s);
+
+ if (!fw_cfg) {
+ return;
+ }
+
+ button_port = g_malloc(sizeof(*button_port));
+ *button_port = cpu_to_le16(s->ioport);
+ fw_cfg_add_file(fw_cfg, "etc/button-port", button_port,
+ sizeof(*button_port));
+}
+
+static const Property button_device_properties[] = {
+ DEFINE_PROP_UINT16(BUTTON_IOPORT_PROP, BUTTONState, ioport, 0x53d),
+ DEFINE_PROP_BOOL("use-qmp", BUTTONState, use_qmp_control, true),
+ DEFINE_PROP_BOOL("enable-procfs", BUTTONState, enable_procfs, false),
+ DEFINE_PROP_UINT64(BUTTON_PROBE_STATE_INTERVAL, BUTTONState,
+ probe_state_interval, 2000),
+ DEFINE_PROP_STRING(BUTTON_PATH_PROP, BUTTONState, button_path),
+};
+
+static const VMStateDescription button_vmstate = {
+ .name = "button",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .fields = (VMStateField[]) {
+ VMSTATE_UINT16(ioport, BUTTONState),
+ VMSTATE_UINT64(probe_state_interval, BUTTONState),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+static void build_button_aml(AcpiDevAmlIf *adev, Aml *scope)
+{
+ Aml *dev, *field, *method;
+ Aml *button_state;
+ Aml *sb_scope;
+ BUTTONState *s = BUTTON_DEVICE(adev);
+
+ button_state = aml_local(0);
+
+ sb_scope = aml_scope("\\_SB");
+ dev = aml_device("LID0");
+ aml_append(dev, aml_name_decl("_HID", aml_string("PNP0C0D")));
+
+ aml_append(dev, aml_operation_region("LSTA", AML_SYSTEM_IO,
+ aml_int(s->ioport),
+ BUTTON_LEN));
+ field = aml_field("LSTA", AML_BYTE_ACC, AML_NOLOCK, AML_PRESERVE);
+ aml_append(field, aml_named_field("LIDS", 8));
+ aml_append(dev, field);
+
+ method = aml_method("_LID", 0, AML_NOTSERIALIZED);
+ aml_append(method, aml_store(aml_name("LIDS"), button_state));
+ aml_append(method, aml_return(button_state));
+ aml_append(dev, method);
+
+ aml_append(sb_scope, dev);
+ aml_append(scope, sb_scope);
+
+ /* Status Change */
+ method = aml_method("\\_GPE._E0B", 0, AML_NOTSERIALIZED);
+ aml_append(method, aml_notify(aml_name("\\_SB.LID0"), aml_int(0x80)));
+ aml_append(scope, method);
+}
+
+static void button_class_init(ObjectClass *class, const void *data)
+{
+ DeviceClass *dc = DEVICE_CLASS(class);
+ AcpiDevAmlIfClass *adevc = ACPI_DEV_AML_IF_CLASS(class);
+
+ dc->realize = button_realize;
+ device_class_set_props(dc, button_device_properties);
+ dc->vmsd = &button_vmstate;
+ adevc->build_dev_aml = build_button_aml;
+}
+
+static uint64_t button_ioport_read(void *opaque, hwaddr addr, unsigned size)
+{
+ BUTTONState *s = opaque;
+
+ button_get_dynamic_status(s);
+
+ switch (addr) {
+ case BUTTON_STA_ADDR:
+ return s->lid_state;
+ default:
+ warn_report("Button: guest read unknown value.");
+ trace_button_ioport_read_unknown();
+ return 0;
+ }
+}
+
+static const MemoryRegionOps button_ops = {
+ .read = button_ioport_read,
+ .impl = {
+ .min_access_size = 1,
+ .max_access_size = 1,
+ },
+};
+
+static void button_instance_init(Object *obj)
+{
+ BUTTONState *s = BUTTON_DEVICE(obj);
+
+ memory_region_init_io(&s->io, obj, &button_ops, s, "button",
+ BUTTON_LEN);
+}
+
+static const TypeInfo button_info = {
+ .name = TYPE_BUTTON,
+ .parent = TYPE_ISA_DEVICE,
+ .instance_size = sizeof(BUTTONState),
+ .class_init = button_class_init,
+ .instance_init = button_instance_init,
+ .interfaces = (InterfaceInfo[]) {
+ { TYPE_ACPI_DEV_AML_IF },
+ { },
+ },
+};
+
+static BUTTONState *find_button_device(void)
+{
+ Object *o = object_resolve_path_type("", TYPE_BUTTON, NULL);
+ if (!o) {
+ return NULL;
+ }
+ return BUTTON_DEVICE(o);
+}
+
+void qmp_lid_button_set_state(bool open, Error **errp)
+{
+ BUTTONState *s = find_button_device();
+
+ if (!s) {
+ error_setg(errp, "No lid button device found");
+ return;
+ }
+
+ s->qmp_lid_open = open;
+
+ Object *obj = object_resolve_path_type("", TYPE_ACPI_DEVICE_IF, NULL);
+ if (obj) {
+ acpi_send_event(DEVICE(obj), ACPI_BUTTON_CHANGE_STATUS);
+ }
+}
+
+LidButtonInfo *qmp_query_lid_button(Error **errp)
+{
+ BUTTONState *s = find_button_device();
+ LidButtonInfo *ret;
+
+ if (!s) {
+ error_setg(errp, "No lid button device found");
+ return NULL;
+ }
+
+ ret = g_new0(LidButtonInfo, 1);
+
+ if (s->use_qmp_control) {
+ ret->open = s->qmp_lid_open;
+ } else {
+ button_get_dynamic_status(s);
+ ret->open = (s->lid_state == LID_OPEN);
+ }
+
+ return ret;
+}
+
+static void button_register_types(void)
+{
+ type_register_static(&button_info);
+}
+
+type_init(button_register_types)
diff --git a/hw/acpi/meson.build b/hw/acpi/meson.build
index 2b24951f28..94993ecb9a 100644
--- a/hw/acpi/meson.build
+++ b/hw/acpi/meson.build
@@ -33,6 +33,7 @@ if have_tpm
endif
acpi_ss.add(when: 'CONFIG_BATTERY', if_true: files('battery.c'))
acpi_ss.add(when: 'CONFIG_AC_ADAPTER', if_true: files('acad.c'))
+acpi_ss.add(when: 'CONFIG_BUTTON', if_true: files('button.c'))
system_ss.add(when: 'CONFIG_ACPI', if_false: files('acpi-stub.c', 'aml-build-stub.c', 'ghes-stub.c', 'acpi_interface.c'))
system_ss.add(when: 'CONFIG_ACPI_PCI_BRIDGE', if_false: files('pci-bridge-stub.c'))
system_ss.add_all(when: 'CONFIG_ACPI', if_true: acpi_ss)
diff --git a/hw/acpi/trace-events b/hw/acpi/trace-events
index 68ac6e9701..816f027bb3 100644
--- a/hw/acpi/trace-events
+++ b/hw/acpi/trace-events
@@ -97,3 +97,8 @@ battery_ioport_read_unknown(void) "Battery read unknown"
acad_realize(void) "AC adapter device realize entry"
acad_get_dynamic_status(uint8_t state) "AC adapter read state: %"PRIu8
acad_ioport_read_unknown(void) "AC adapter read unknown"
+
+# button.c
+button_realize(void) "Button device realize entry"
+button_get_dynamic_status(void) "Button read dynamic status entry"
+button_ioport_read_unknown(void) "Button read unknown"
diff --git a/hw/i386/Kconfig b/hw/i386/Kconfig
index baab382a2e..1d2d809028 100644
--- a/hw/i386/Kconfig
+++ b/hw/i386/Kconfig
@@ -41,6 +41,7 @@ config PC
imply FDC_ISA
imply BATTERY
imply AC_ADAPTER
+ imply BUTTON
select I8259
select I8254
select PCKBD
diff --git a/include/hw/acpi/acpi_dev_interface.h b/include/hw/acpi/acpi_dev_interface.h
index 588fbbd05f..4f5bcc15da 100644
--- a/include/hw/acpi/acpi_dev_interface.h
+++ b/include/hw/acpi/acpi_dev_interface.h
@@ -15,6 +15,7 @@ typedef enum {
ACPI_POWER_DOWN_STATUS = 64,
ACPI_BATTERY_CHANGE_STATUS = 128,
ACPI_AC_ADAPTER_CHANGE_STATUS = 1024,
+ ACPI_BUTTON_CHANGE_STATUS = 2048,
} AcpiEventStatusBits;
#define TYPE_ACPI_DEVICE_IF "acpi-device-interface"
diff --git a/include/hw/acpi/button.h b/include/hw/acpi/button.h
new file mode 100644
index 0000000000..fa5f7001b2
--- /dev/null
+++ b/include/hw/acpi/button.h
@@ -0,0 +1,25 @@
+/*
+ * QEMU emulated button device.
+ *
+ * Copyright (c) 2019 Janus Technologies, Inc. (http://janustech.com)
+ *
+ * Authors:
+ * Leonid Bloch <lb.workbox@gmail.com>
+ * Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
+ * Dmitry Fleytman <dmitry.fleytman@gmail.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ */
+
+#ifndef HW_ACPI_BUTTON_H
+#define HW_ACPI_BUTTON_H
+
+#define TYPE_BUTTON "button"
+#define BUTTON_IOPORT_PROP "ioport"
+#define BUTTON_PATH_PROP "procfs_path"
+#define BUTTON_PROBE_STATE_INTERVAL "probe_interval"
+
+#define BUTTON_LEN 1
+
+#endif
diff --git a/qapi/acpi.json b/qapi/acpi.json
index 52e151f0e6..bcbddbfbd5 100644
--- a/qapi/acpi.json
+++ b/qapi/acpi.json
@@ -264,3 +264,52 @@
##
{ 'command': 'query-ac-adapter',
'returns': 'AcAdapterInfo' }
+
+##
+# @lid-button-set-state:
+#
+# Set the state of the emulated laptop lid button device
+#
+# @open: whether the lid is open
+#
+
+#
+# Since: 10.2
+#
+# .. qmp-example::
+#
+# -> { "execute": "lid-button-set-state",
+# "arguments": { "open": true } }
+# <- { "return": {} }
+##
+{ 'command': 'lid-button-set-state',
+ 'data': { 'open': 'bool' } }
+
+##
+# @LidButtonInfo:
+#
+# Lid button state information
+#
+# @open: whether the lid is open
+#
+# Since: 10.2
+##
+{ 'struct': 'LidButtonInfo',
+ 'data': { 'open': 'bool' } }
+
+##
+# @query-lid-button:
+#
+# Query the current state of the emulated laptop lid button device
+#
+# Returns: lid button state
+#
+# Since: 10.2
+#
+# .. qmp-example::
+#
+# -> { "execute": "query-lid-button" }
+# <- { "return": { "open": true } }
+##
+{ 'command': 'query-lid-button',
+ 'returns': 'LidButtonInfo' }
--
2.50.1
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [PATCH v2 0/4] Introduce a battery, AC adapter, and lid button
2025-08-21 17:45 [PATCH v2 0/4] Introduce a battery, AC adapter, and lid button Leonid Bloch
` (3 preceding siblings ...)
2025-08-21 17:45 ` [PATCH v2 4/4] hw/acpi: Introduce the QEMU lid button Leonid Bloch
@ 2025-08-21 18:03 ` Leonid Bloch
4 siblings, 0 replies; 7+ messages in thread
From: Leonid Bloch @ 2025-08-21 18:03 UTC (permalink / raw)
To: Michael S . Tsirkin, Igor Mammedov, Ani Sinha, Paolo Bonzini,
Richard Henderson, Eduardo Habkost, Eric Blake, Markus Armbruster,
Marcel Apfelbaum, Dmitry Fleytman
Cc: qemu-devel
[-- Attachment #1: Type: text/plain, Size: 4404 bytes --]
GitHub PR for ease of review: https://github.com/blochl/qemu/pull/2
Link to v1:
https://lists.gnu.org/archive/html/qemu-devel/2021-01/msg05246.html
On Thu, Aug 21, 2025 at 8:46 PM Leonid Bloch <lb.workbox@gmail.com> wrote:
> First, I must apologize for the extremely long delay since v1 - it has been
> nearly 4 years, which is unacceptable. Life circumstances intervened.
>
> This series introduces three ACPI devices that are particularly useful
> for laptop/mobile virtualization:
>
> * Battery
> * AC adapter
> * Laptop lid button
>
> Changes in v2:
> --------------
> Based on the feedback from Philippe Mathieu-Daudé and Michael S. Tsirkin:
>
> * Complete redesign with dual-mode operation:
> - QMP control mode (default): Devices are controlled via QMP commands,
> providing deterministic behavior essential for migration and CI/testing
> - Host mirroring mode (opt-in): Original sysfs/procfs monitoring
> behavior,
> now disabled by default
>
> * Migrated to modern QEMU ACPI architecture:
> - Devices now implement ACPI_DEV_AML_IF interface
> - AML generation moved from centralized acpi-build.c to device files
>
> * Added a QMP interface:
> - battery-set-state/query-battery
> - ac-adapter-set-state/query-ac-adapter
> - lid-button-set-state/query-lid-button
>
> * Documentation improvements:
> - Converted to .rst format
> - Added examples for both QMP and "fake" sysfs/procfs testing
>
> The dual-mode design ensures these devices are migration-safe and
> deterministic by default, while still allowing host state mirroring
> when explicitly requested for desktop use cases.
>
> Use cases:
> ----------
> 1. Testing: CI systems can programmatically control power states
> 2. Cloud: Expose virtual battery for usage-based resource limiting
> 3. Desktop virtualization: Mirror host laptop state to guest (opt-in)
> 4. Development: Test power management without physical hardware
>
> Example usage:
> --------------
> # Default QMP-controlled battery
> qemu-system-x86_64 -device battery
>
> # Mirror host battery
> qemu-system-x86_64 -device battery,use-qmp=false,enable-sysfs=true
>
> # Control via QMP
> {"execute": "battery-set-state",
> "arguments": {"state": {"present": true, "charging": false,
> "discharging": true, "charge-percent": 42,
> "rate": 500}}}
>
> The series has been tested with Windows and Linux guests, correctly
> showing battery status, AC adapter state, and lid button events in
> guest UIs and triggering appropriate power management actions.
>
> Thanks again for your patience and feedback.
> Leonid.
>
> Leonid Bloch (4):
> hw/acpi: Increase the number of possible ACPI interrupts
> hw/acpi: Introduce the QEMU Battery
> hw/acpi: Introduce the QEMU AC adapter
> hw/acpi: Introduce the QEMU lid button
>
> MAINTAINERS | 18 +
> docs/specs/acad.rst | 195 +++++++
> docs/specs/battery.rst | 225 ++++++++
> docs/specs/button.rst | 189 +++++++
> docs/specs/index.rst | 3 +
> hw/acpi/Kconfig | 12 +
> hw/acpi/acad.c | 447 ++++++++++++++++
> hw/acpi/battery.c | 735 +++++++++++++++++++++++++++
> hw/acpi/button.c | 438 ++++++++++++++++
> hw/acpi/core.c | 17 +-
> hw/acpi/meson.build | 3 +
> hw/acpi/trace-events | 15 +
> hw/i386/Kconfig | 3 +
> hw/i386/acpi-build.c | 1 +
> include/hw/acpi/acad.h | 27 +
> include/hw/acpi/acpi_dev_interface.h | 3 +
> include/hw/acpi/battery.h | 33 ++
> include/hw/acpi/button.h | 25 +
> qapi/acpi.json | 171 +++++++
> 19 files changed, 2558 insertions(+), 2 deletions(-)
> create mode 100644 docs/specs/acad.rst
> create mode 100644 docs/specs/battery.rst
> create mode 100644 docs/specs/button.rst
> create mode 100644 hw/acpi/acad.c
> create mode 100644 hw/acpi/battery.c
> create mode 100644 hw/acpi/button.c
> create mode 100644 include/hw/acpi/acad.h
> create mode 100644 include/hw/acpi/battery.h
> create mode 100644 include/hw/acpi/button.h
>
> --
> 2.50.1
>
>
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^ permalink raw reply [flat|nested] 7+ messages in thread