qemu/hw/acpi/cpu_hotplug.c
Ani Sinha 7b393b7142 hw/acpi: changes towards enabling -Wshadow=local
Code changes in acpi that addresses all compiler complaints coming from enabling
-Wshadow flags. Enabling -Wshadow catches cases of local variables shadowing
other local variables or parameters. These makes the code confusing and/or adds
bugs that are difficult to catch.  See also

    Subject: Help wanted for enabling -Wshadow=local
    Message-Id: <87r0mqlf9x.fsf@pond.sub.org>
    https://lore.kernel.org/qemu-devel/87r0mqlf9x.fsf@pond.sub.org

The code is tested to build with and without the flag turned on.

CC: Markus Armbruster <armbru@redhat.com>
CC: Philippe Mathieu-Daude <philmd@linaro.org>
CC: mst@redhat.com
CC: imammedo@redhat.com
Signed-off-by: Ani Sinha <anisinha@redhat.com>
Message-ID: <20230922124203.127110-1-anisinha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
[Commit message tweaked]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2023-09-29 10:07:18 +02:00

338 lines
12 KiB
C

/*
* QEMU ACPI hotplug utilities
*
* Copyright (C) 2013 Red Hat Inc
*
* Authors:
* Igor Mammedov <imammedo@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "hw/acpi/cpu_hotplug.h"
#include "qapi/error.h"
#include "hw/core/cpu.h"
#include "hw/i386/pc.h"
#include "hw/pci/pci.h"
#include "qemu/error-report.h"
#define CPU_EJECT_METHOD "CPEJ"
#define CPU_MAT_METHOD "CPMA"
#define CPU_ON_BITMAP "CPON"
#define CPU_STATUS_METHOD "CPST"
#define CPU_STATUS_MAP "PRS"
#define CPU_SCAN_METHOD "PRSC"
static uint64_t cpu_status_read(void *opaque, hwaddr addr, unsigned int size)
{
AcpiCpuHotplug *cpus = opaque;
uint64_t val = cpus->sts[addr];
return val;
}
static void cpu_status_write(void *opaque, hwaddr addr, uint64_t data,
unsigned int size)
{
/* firmware never used to write in CPU present bitmap so use
this fact as means to switch QEMU into modern CPU hotplug
mode by writing 0 at the beginning of legacy CPU bitmap
*/
if (addr == 0 && data == 0) {
AcpiCpuHotplug *cpus = opaque;
object_property_set_bool(cpus->device, "cpu-hotplug-legacy", false,
&error_abort);
}
}
static const MemoryRegionOps AcpiCpuHotplug_ops = {
.read = cpu_status_read,
.write = cpu_status_write,
.endianness = DEVICE_LITTLE_ENDIAN,
.valid = {
.min_access_size = 1,
.max_access_size = 4,
},
.impl = {
.max_access_size = 1,
},
};
static void acpi_set_cpu_present_bit(AcpiCpuHotplug *g, CPUState *cpu)
{
CPUClass *k = CPU_GET_CLASS(cpu);
int64_t cpu_id;
cpu_id = k->get_arch_id(cpu);
if ((cpu_id / 8) >= ACPI_GPE_PROC_LEN) {
object_property_set_bool(g->device, "cpu-hotplug-legacy", false,
&error_abort);
return;
}
g->sts[cpu_id / 8] |= (1 << (cpu_id % 8));
}
void legacy_acpi_cpu_plug_cb(HotplugHandler *hotplug_dev,
AcpiCpuHotplug *g, DeviceState *dev, Error **errp)
{
acpi_set_cpu_present_bit(g, CPU(dev));
acpi_send_event(DEVICE(hotplug_dev), ACPI_CPU_HOTPLUG_STATUS);
}
void legacy_acpi_cpu_hotplug_init(MemoryRegion *parent, Object *owner,
AcpiCpuHotplug *gpe_cpu, uint16_t base)
{
CPUState *cpu;
memory_region_init_io(&gpe_cpu->io, owner, &AcpiCpuHotplug_ops,
gpe_cpu, "acpi-cpu-hotplug", ACPI_GPE_PROC_LEN);
memory_region_add_subregion(parent, base, &gpe_cpu->io);
gpe_cpu->device = owner;
CPU_FOREACH(cpu) {
acpi_set_cpu_present_bit(gpe_cpu, cpu);
}
}
void acpi_switch_to_modern_cphp(AcpiCpuHotplug *gpe_cpu,
CPUHotplugState *cpuhp_state,
uint16_t io_port)
{
MemoryRegion *parent = pci_address_space_io(PCI_DEVICE(gpe_cpu->device));
memory_region_del_subregion(parent, &gpe_cpu->io);
cpu_hotplug_hw_init(parent, gpe_cpu->device, cpuhp_state, io_port);
}
void build_legacy_cpu_hotplug_aml(Aml *ctx, MachineState *machine,
uint16_t io_base)
{
Aml *dev;
Aml *crs;
Aml *pkg;
Aml *field;
Aml *method;
Aml *if_ctx;
Aml *else_ctx;
int i, apic_idx;
Aml *sb_scope = aml_scope("_SB");
uint8_t madt_tmpl[8] = {0x00, 0x08, 0x00, 0x00, 0x00, 0, 0, 0};
Aml *cpu_id = aml_arg(1);
Aml *apic_id = aml_arg(0);
Aml *cpu_on = aml_local(0);
Aml *madt = aml_local(1);
Aml *cpus_map = aml_name(CPU_ON_BITMAP);
Aml *zero = aml_int(0);
Aml *one = aml_int(1);
MachineClass *mc = MACHINE_GET_CLASS(machine);
const CPUArchIdList *apic_ids = mc->possible_cpu_arch_ids(machine);
X86MachineState *x86ms = X86_MACHINE(machine);
/*
* _MAT method - creates an madt apic buffer
* apic_id = Arg0 = Local APIC ID
* cpu_id = Arg1 = Processor ID
* cpu_on = Local0 = CPON flag for this cpu
* madt = Local1 = Buffer (in madt apic form) to return
*/
method = aml_method(CPU_MAT_METHOD, 2, AML_NOTSERIALIZED);
aml_append(method,
aml_store(aml_derefof(aml_index(cpus_map, apic_id)), cpu_on));
aml_append(method,
aml_store(aml_buffer(sizeof(madt_tmpl), madt_tmpl), madt));
/* Update the processor id, lapic id, and enable/disable status */
aml_append(method, aml_store(cpu_id, aml_index(madt, aml_int(2))));
aml_append(method, aml_store(apic_id, aml_index(madt, aml_int(3))));
aml_append(method, aml_store(cpu_on, aml_index(madt, aml_int(4))));
aml_append(method, aml_return(madt));
aml_append(sb_scope, method);
/*
* _STA method - return ON status of cpu
* apic_id = Arg0 = Local APIC ID
* cpu_on = Local0 = CPON flag for this cpu
*/
method = aml_method(CPU_STATUS_METHOD, 1, AML_NOTSERIALIZED);
aml_append(method,
aml_store(aml_derefof(aml_index(cpus_map, apic_id)), cpu_on));
if_ctx = aml_if(cpu_on);
{
aml_append(if_ctx, aml_return(aml_int(0xF)));
}
aml_append(method, if_ctx);
else_ctx = aml_else();
{
aml_append(else_ctx, aml_return(zero));
}
aml_append(method, else_ctx);
aml_append(sb_scope, method);
method = aml_method(CPU_EJECT_METHOD, 2, AML_NOTSERIALIZED);
aml_append(method, aml_sleep(200));
aml_append(sb_scope, method);
method = aml_method(CPU_SCAN_METHOD, 0, AML_NOTSERIALIZED);
{
Aml *while_ctx, *if_ctx2, *else_ctx2;
Aml *bus_check_evt = aml_int(1);
Aml *remove_evt = aml_int(3);
Aml *status_map = aml_local(5); /* Local5 = active cpu bitmap */
Aml *byte = aml_local(2); /* Local2 = last read byte from bitmap */
Aml *idx = aml_local(0); /* Processor ID / APIC ID iterator */
Aml *is_cpu_on = aml_local(1); /* Local1 = CPON flag for cpu */
Aml *status = aml_local(3); /* Local3 = active state for cpu */
aml_append(method, aml_store(aml_name(CPU_STATUS_MAP), status_map));
aml_append(method, aml_store(zero, byte));
aml_append(method, aml_store(zero, idx));
/* While (idx < SizeOf(CPON)) */
while_ctx = aml_while(aml_lless(idx, aml_sizeof(cpus_map)));
aml_append(while_ctx,
aml_store(aml_derefof(aml_index(cpus_map, idx)), is_cpu_on));
if_ctx = aml_if(aml_and(idx, aml_int(0x07), NULL));
{
/* Shift down previously read bitmap byte */
aml_append(if_ctx, aml_shiftright(byte, one, byte));
}
aml_append(while_ctx, if_ctx);
else_ctx = aml_else();
{
/* Read next byte from cpu bitmap */
aml_append(else_ctx, aml_store(aml_derefof(aml_index(status_map,
aml_shiftright(idx, aml_int(3), NULL))), byte));
}
aml_append(while_ctx, else_ctx);
aml_append(while_ctx, aml_store(aml_and(byte, one, NULL), status));
if_ctx = aml_if(aml_lnot(aml_equal(is_cpu_on, status)));
{
/* State change - update CPON with new state */
aml_append(if_ctx, aml_store(status, aml_index(cpus_map, idx)));
if_ctx2 = aml_if(aml_equal(status, one));
{
aml_append(if_ctx2,
aml_call2(AML_NOTIFY_METHOD, idx, bus_check_evt));
}
aml_append(if_ctx, if_ctx2);
else_ctx2 = aml_else();
{
aml_append(else_ctx2,
aml_call2(AML_NOTIFY_METHOD, idx, remove_evt));
}
}
aml_append(if_ctx, else_ctx2);
aml_append(while_ctx, if_ctx);
aml_append(while_ctx, aml_increment(idx)); /* go to next cpu */
aml_append(method, while_ctx);
}
aml_append(sb_scope, method);
/* The current AML generator can cover the APIC ID range [0..255],
* inclusive, for VCPU hotplug. */
QEMU_BUILD_BUG_ON(ACPI_CPU_HOTPLUG_ID_LIMIT > 256);
if (x86ms->apic_id_limit > ACPI_CPU_HOTPLUG_ID_LIMIT) {
error_report("max_cpus is too large. APIC ID of last CPU is %u",
x86ms->apic_id_limit - 1);
exit(1);
}
/* create PCI0.PRES device and its _CRS to reserve CPU hotplug MMIO */
dev = aml_device("PCI0." stringify(CPU_HOTPLUG_RESOURCE_DEVICE));
aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0A06")));
aml_append(dev,
aml_name_decl("_UID", aml_string("CPU Hotplug resources"))
);
/* device present, functioning, decoding, not shown in UI */
aml_append(dev, aml_name_decl("_STA", aml_int(0xB)));
crs = aml_resource_template();
aml_append(crs,
aml_io(AML_DECODE16, io_base, io_base, 1, ACPI_GPE_PROC_LEN)
);
aml_append(dev, aml_name_decl("_CRS", crs));
aml_append(sb_scope, dev);
/* declare CPU hotplug MMIO region and PRS field to access it */
aml_append(sb_scope, aml_operation_region(
"PRST", AML_SYSTEM_IO, aml_int(io_base), ACPI_GPE_PROC_LEN));
field = aml_field("PRST", AML_BYTE_ACC, AML_NOLOCK, AML_PRESERVE);
aml_append(field, aml_named_field("PRS", 256));
aml_append(sb_scope, field);
/* build Processor object for each processor */
for (i = 0; i < apic_ids->len; i++) {
int cpu_apic_id = apic_ids->cpus[i].arch_id;
assert(cpu_apic_id < ACPI_CPU_HOTPLUG_ID_LIMIT);
dev = aml_processor(i, 0, 0, "CP%.02X", cpu_apic_id);
method = aml_method("_MAT", 0, AML_NOTSERIALIZED);
aml_append(method,
aml_return(aml_call2(CPU_MAT_METHOD,
aml_int(cpu_apic_id), aml_int(i))
));
aml_append(dev, method);
method = aml_method("_STA", 0, AML_NOTSERIALIZED);
aml_append(method,
aml_return(aml_call1(CPU_STATUS_METHOD, aml_int(cpu_apic_id))));
aml_append(dev, method);
method = aml_method("_EJ0", 1, AML_NOTSERIALIZED);
aml_append(method,
aml_return(aml_call2(CPU_EJECT_METHOD, aml_int(cpu_apic_id),
aml_arg(0)))
);
aml_append(dev, method);
aml_append(sb_scope, dev);
}
/* build this code:
* Method(NTFY, 2) {If (LEqual(Arg0, 0x00)) {Notify(CP00, Arg1)} ...}
*/
/* Arg0 = APIC ID */
method = aml_method(AML_NOTIFY_METHOD, 2, AML_NOTSERIALIZED);
for (i = 0; i < apic_ids->len; i++) {
int cpu_apic_id = apic_ids->cpus[i].arch_id;
if_ctx = aml_if(aml_equal(aml_arg(0), aml_int(cpu_apic_id)));
aml_append(if_ctx,
aml_notify(aml_name("CP%.02X", cpu_apic_id), aml_arg(1))
);
aml_append(method, if_ctx);
}
aml_append(sb_scope, method);
/* build "Name(CPON, Package() { One, One, ..., Zero, Zero, ... })"
*
* Note: The ability to create variable-sized packages was first
* introduced in ACPI 2.0. ACPI 1.0 only allowed fixed-size packages
* ith up to 255 elements. Windows guests up to win2k8 fail when
* VarPackageOp is used.
*/
pkg = x86ms->apic_id_limit <= 255 ? aml_package(x86ms->apic_id_limit) :
aml_varpackage(x86ms->apic_id_limit);
for (i = 0, apic_idx = 0; i < apic_ids->len; i++) {
int cpu_apic_id = apic_ids->cpus[i].arch_id;
for (; apic_idx < cpu_apic_id; apic_idx++) {
aml_append(pkg, aml_int(0));
}
aml_append(pkg, aml_int(apic_ids->cpus[i].cpu ? 1 : 0));
apic_idx = cpu_apic_id + 1;
}
aml_append(sb_scope, aml_name_decl(CPU_ON_BITMAP, pkg));
aml_append(ctx, sb_scope);
method = aml_method("\\_GPE._E02", 0, AML_NOTSERIALIZED);
aml_append(method, aml_call0("\\_SB." CPU_SCAN_METHOD));
aml_append(ctx, method);
}