This provides the required user space stubs to enable the in-kernel
i8254 emulation of KVM.
The in-kernel model supports lost tick compensation according to the
"delay" policy. This is enabled by default and can be switched off via a
device property.
Depending on the feature set of the host kernel (before 2.6.32), we may
have to disable the HPET or lack sound output from the PC speaker.
Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
---
Makefile.target | 2 +-
hw/i8254.h | 11 +++
hw/kvm/i8254.c | 237 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
hw/pc.c | 14 +++-
4 files changed, 261 insertions(+), 3 deletions(-)
create mode 100644 hw/kvm/i8254.c
diff --git a/Makefile.target b/Makefile.target
index 68481a3..2af5511 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -235,7 +235,7 @@ obj-i386-y += vmport.o
obj-i386-y += pci-hotplug.o smbios.o wdt_ib700.o
obj-i386-y += debugcon.o multiboot.o
obj-i386-y += pc_piix.o
-obj-i386-$(CONFIG_KVM) += kvm/clock.o kvm/apic.o kvm/i8259.o kvm/ioapic.o
+obj-i386-$(CONFIG_KVM) += kvm/clock.o kvm/apic.o kvm/i8259.o kvm/ioapic.o kvm/i8254.o
obj-i386-$(CONFIG_SPICE) += qxl.o qxl-logger.o qxl-render.o
# shared objects
diff --git a/hw/i8254.h b/hw/i8254.h
index a1d2e98..ba6b598 100644
--- a/hw/i8254.h
+++ b/hw/i8254.h
@@ -51,6 +51,17 @@ static inline ISADevice *pit_init(ISABus *bus, int base, int isa_irq,
return dev;
}
+static inline ISADevice *kvm_pit_init(ISABus *bus, int base)
+{
+ ISADevice *dev;
+
+ dev = isa_create(bus, "kvm-pit");
+ qdev_prop_set_uint32(&dev->qdev, "iobase", base);
+ qdev_init_nofail(&dev->qdev);
+
+ return dev;
+}
+
void pit_set_gate(ISADevice *dev, int channel, int val);
void pit_get_channel_info(ISADevice *dev, int channel, PITChannelInfo *info);
diff --git a/hw/kvm/i8254.c b/hw/kvm/i8254.c
new file mode 100644
index 0000000..0d7196a
--- /dev/null
+++ b/hw/kvm/i8254.c
@@ -0,0 +1,237 @@
+/*
+ * KVM in-kernel PIT (i8254) support
+ *
+ * Copyright (c) 2012 Siemens AG
+ *
+ * Authors:
+ * Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
+ *
+ * This work is licensed under the terms of the GNU GPL version 2.
+ * See the COPYING file in the top-level directory.
+ */
+#include "qemu-timer.h"
+#include "hw/i8254.h"
+#include "hw/i8254_internal.h"
+#include "kvm.h"
+
+#define KVM_PIT_REINJECT_BIT 0
+
+typedef struct KVMPITState {
+ PITCommonState pit;
+ LostTickPolicy lost_tick_policy;
+} KVMPITState;
+
+static void kvm_pit_get(PITCommonState *s)
+{
+ struct kvm_pit_state2 kpit;
+ struct kvm_pit_channel_state *kchan;
+ struct PITChannelState *sc;
+ int i, ret;
+
+ if (kvm_has_pit_state2()) {
+ ret = kvm_vm_ioctl(kvm_state, KVM_GET_PIT2, &kpit);
+ if (ret < 0) {
+ fprintf(stderr, "KVM_GET_PIT2 failed: %s\n", strerror(ret));
+ abort();
+ }
+ s->channels[0].irq_disabled = kpit.flags & KVM_PIT_FLAGS_HPET_LEGACY;
+ } else {
+ /*
+ * kvm_pit_state2 is superset of kvm_pit_state struct,
+ * so we can use it for KVM_GET_PIT as well.
+ */
+ ret = kvm_vm_ioctl(kvm_state, KVM_GET_PIT, &kpit);
+ if (ret < 0) {
+ fprintf(stderr, "KVM_GET_PIT failed: %s\n", strerror(ret));
+ abort();
+ }
+ }
+ for (i = 0; i < 3; i++) {
+ kchan = &kpit.channels[i];
+ sc = &s->channels[i];
+ sc->count = kchan->count;
+ sc->latched_count = kchan->latched_count;
+ sc->count_latched = kchan->count_latched;
+ sc->status_latched = kchan->status_latched;
+ sc->status = kchan->status;
+ sc->read_state = kchan->read_state;
+ sc->write_state = kchan->write_state;
+ sc->write_latch = kchan->write_latch;
+ sc->rw_mode = kchan->rw_mode;
+ sc->mode = kchan->mode;
+ sc->bcd = kchan->bcd;
+ sc->gate = kchan->gate;
+ sc->count_load_time = kchan->count_load_time;
+ }
+
+ sc = &s->channels[0];
+ sc->next_transition_time =
+ pit_get_next_transition_time(sc, sc->count_load_time);
+}
+
+static void kvm_pit_put(PITCommonState *s)
+{
+ struct kvm_pit_state2 kpit;
+ struct kvm_pit_channel_state *kchan;
+ struct PITChannelState *sc;
+ int i, ret;
+
+ kpit.flags = s->channels[0].irq_disabled ? KVM_PIT_FLAGS_HPET_LEGACY : 0;
+ for (i = 0; i < 3; i++) {
+ kchan = &kpit.channels[i];
+ sc = &s->channels[i];
+ kchan->count = sc->count;
+ kchan->latched_count = sc->latched_count;
+ kchan->count_latched = sc->count_latched;
+ kchan->status_latched = sc->status_latched;
+ kchan->status = sc->status;
+ kchan->read_state = sc->read_state;
+ kchan->write_state = sc->write_state;
+ kchan->write_latch = sc->write_latch;
+ kchan->rw_mode = sc->rw_mode;
+ kchan->mode = sc->mode;
+ kchan->bcd = sc->bcd;
+ kchan->gate = sc->gate;
+ kchan->count_load_time = sc->count_load_time;
+ }
+
+ ret = kvm_vm_ioctl(kvm_state,
+ kvm_has_pit_state2() ? KVM_SET_PIT2 : KVM_SET_PIT,
+ &kpit);
+ if (ret < 0) {
+ fprintf(stderr, "%s failed: %s\n",
+ kvm_has_pit_state2() ? "KVM_SET_PIT2" : "KVM_SET_PIT",
+ strerror(ret));
+ abort();
+ }
+}
+
+static void kvm_pit_set_gate(PITCommonState *s, PITChannelState *sc, int val)
+{
+ kvm_pit_get(s);
+
+ switch (sc->mode) {
+ default:
+ case 0:
+ case 4:
+ /* XXX: just disable/enable counting */
+ break;
+ case 1:
+ case 2:
+ case 3:
+ case 5:
+ if (sc->gate < val) {
+ /* restart counting on rising edge */
+ sc->count_load_time = qemu_get_clock_ns(vm_clock);
+ }
+ break;
+ }
+ sc->gate = val;
+
+ kvm_pit_put(s);
+}
+
+static void kvm_pit_get_channel_info(PITCommonState *s, PITChannelState *sc,
+ PITChannelInfo *info)
+{
+ kvm_pit_get(s);
+
+ pit_get_channel_info_common(s, sc, info);
+}
+
+static void kvm_pit_reset(DeviceState *dev)
+{
+ PITCommonState *s = DO_UPCAST(PITCommonState, dev.qdev, dev);
+
+ pit_reset_common(s);
+
+ kvm_pit_put(s);
+}
+
+static void kvm_pit_irq_control(void *opaque, int n, int enable)
+{
+ PITCommonState *pit = opaque;
+ PITChannelState *s = &pit->channels[0];
+
+ kvm_pit_get(pit);
+
+ s->irq_disabled = !enable;
+
+ kvm_pit_put(pit);
+}
+
+static int kvm_pit_initfn(PITCommonState *pit)
+{
+ KVMPITState *s = DO_UPCAST(KVMPITState, pit, pit);
+ struct kvm_pit_config config = {
+ .flags = 0,
+ };
+ int ret;
+
+ if (kvm_check_extension(kvm_state, KVM_CAP_PIT2)) {
+ ret = kvm_vm_ioctl(kvm_state, KVM_CREATE_PIT2, &config);
+ } else {
+ ret = kvm_vm_ioctl(kvm_state, KVM_CREATE_PIT);
+ }
+ if (ret < 0) {
+ fprintf(stderr, "Create kernel PIC irqchip failed: %s\n",
+ strerror(ret));
+ return ret;
+ }
+ switch (s->lost_tick_policy) {
+ case LOST_TICK_DELAY:
+ break; /* enabled by default */
+ case LOST_TICK_DISCARD:
+ if (kvm_check_extension(kvm_state, KVM_CAP_REINJECT_CONTROL)) {
+ struct kvm_reinject_control control = { .pit_reinject = 0 };
+
+ ret = kvm_vm_ioctl(kvm_state, KVM_REINJECT_CONTROL, &control);
+ if (ret < 0) {
+ fprintf(stderr,
+ "Can't disable in-kernel PIT reinjection: %s\n",
+ strerror(ret));
+ return ret;
+ }
+ }
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ memory_region_init_reservation(&pit->ioports, "kvm-pit", 4);
+
+ qdev_init_gpio_in(&pit->dev.qdev, kvm_pit_irq_control, 1);
+
+ return 0;
+}
+
+static void kvm_pit_class_init(ObjectClass *klass, void *data)
+{
+ PITCommonClass *k = PIT_COMMON_CLASS(klass);
+
+ k->init = kvm_pit_initfn;
+ k->set_channel_gate = kvm_pit_set_gate;
+ k->get_channel_info = kvm_pit_get_channel_info;
+ k->pre_save = kvm_pit_get;
+ k->post_load = kvm_pit_put;
+}
+
+static DeviceInfo kvm_pit_info = {
+ .name = "kvm-pit",
+ .size = sizeof(KVMPITState),
+ .reset = kvm_pit_reset,
+ .class_init = kvm_pit_class_init,
+ .props = (Property[]) {
+ DEFINE_PROP_HEX32("iobase", KVMPITState, pit.iobase, -1),
+ DEFINE_PROP_LOSTTICKPOLICY("lost_tick_policy", KVMPITState,
+ lost_tick_policy, LOST_TICK_DELAY),
+ DEFINE_PROP_END_OF_LIST(),
+ },
+};
+
+static void kvm_pit_register(void)
+{
+ pit_qdev_register(&kvm_pit_info);
+}
+
+device_init(kvm_pit_register)
diff --git a/hw/pc.c b/hw/pc.c
index d298dc2..33f3823 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -1149,7 +1149,13 @@ void pc_basic_device_init(ISABus *isa_bus, qemu_irq *gsi,
register_ioport_write(0xf0, 1, 1, ioportF0_write, NULL);
- if (!no_hpet) {
+ /*
+ * Check if an HPET shall be created.
+ *
+ * Without KVM_CAP_PIT_STATE2, we cannot switch off the in-kernel PIT
+ * when the HPET wants to take over. Thus we have to disable the latter.
+ */
+ if (!no_hpet && (!kvm_irqchip_in_kernel() || kvm_has_pit_state2())) {
hpet = sysbus_try_create_simple("hpet", HPET_BASE, NULL);
if (hpet) {
@@ -1165,7 +1171,11 @@ void pc_basic_device_init(ISABus *isa_bus, qemu_irq *gsi,
qemu_register_boot_set(pc_boot_set, *rtc_state);
- pit = pit_init(isa_bus, 0x40, pit_isa_irq, pit_alt_irq);
+ if (kvm_irqchip_in_kernel()) {
+ pit = kvm_pit_init(isa_bus, 0x40);
+ } else {
+ pit = pit_init(isa_bus, 0x40, pit_isa_irq, pit_alt_irq);
+ }
if (hpet) {
/* connect PIT to output control line of the HPET */
qdev_connect_gpio_out(hpet, 0, qdev_get_gpio_in(&pit->qdev, 0));
--
1.7.3.4
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