diff mbox series

[v3] pc: Implement -no-hpet as sugar for -machine hpet=on

Message ID 20201021144716.1536388-1-ehabkost@redhat.com
State New
Headers show
Series [v3] pc: Implement -no-hpet as sugar for -machine hpet=on | expand

Commit Message

Eduardo Habkost Oct. 21, 2020, 2:47 p.m. UTC
Get rid of yet another global variable.

The default will be hpet=on only if CONFIG_HPET=y.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
Changes v2 -> v3:
* Revert v2 changes (use "hpet" property), plus:
* Default to hpet=off if CONFIG_HPET=n
* Error out if creation of HPET device fails and hpet=on

Changes v1 -> v2:
* Rename property to "allow-hpet" to make its semantic clearer,
  as it won't make sure HPET is created if CONFIG_HPET=n
* Use qdev_new(TYPE_HPET) at pc_basic_device_init()
---
 include/hw/i386/pc.h  |  1 +
 include/hw/i386/x86.h |  3 ---
 hw/i386/pc.c          | 61 +++++++++++++++++++++++++++++--------------
 hw/i386/pc_piix.c     |  2 +-
 softmmu/vl.c          |  4 +--
 5 files changed, 46 insertions(+), 25 deletions(-)

Comments

Paolo Bonzini Oct. 21, 2020, 3:28 p.m. UTC | #1
On 21/10/20 16:47, Eduardo Habkost wrote:
> Get rid of yet another global variable.

> 

> The default will be hpet=on only if CONFIG_HPET=y.

> 

> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

> ---

> Changes v2 -> v3:

> * Revert v2 changes (use "hpet" property), plus:

> * Default to hpet=off if CONFIG_HPET=n

> * Error out if creation of HPET device fails and hpet=on

> 

> Changes v1 -> v2:

> * Rename property to "allow-hpet" to make its semantic clearer,

>   as it won't make sure HPET is created if CONFIG_HPET=n

> * Use qdev_new(TYPE_HPET) at pc_basic_device_init()

> ---

>  include/hw/i386/pc.h  |  1 +

>  include/hw/i386/x86.h |  3 ---

>  hw/i386/pc.c          | 61 +++++++++++++++++++++++++++++--------------

>  hw/i386/pc_piix.c     |  2 +-

>  softmmu/vl.c          |  4 +--

>  5 files changed, 46 insertions(+), 25 deletions(-)

> 

> diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h

> index 84639d0ebc..911e460097 100644

> --- a/include/hw/i386/pc.h

> +++ b/include/hw/i386/pc.h

> @@ -43,6 +43,7 @@ typedef struct PCMachineState {

>      bool smbus_enabled;

>      bool sata_enabled;

>      bool pit_enabled;

> +    bool hpet_enabled;

>  

>      /* NUMA information: */

>      uint64_t numa_nodes;

> diff --git a/include/hw/i386/x86.h b/include/hw/i386/x86.h

> index d5dcf7a07f..4e66a15ff5 100644

> --- a/include/hw/i386/x86.h

> +++ b/include/hw/i386/x86.h

> @@ -124,7 +124,4 @@ qemu_irq x86_allocate_cpu_irq(void);

>  void gsi_handler(void *opaque, int n, int level);

>  void ioapic_init_gsi(GSIState *gsi_state, const char *parent_name);

>  

> -/* hpet.c */

> -extern int no_hpet;

> -

>  #endif

> diff --git a/hw/i386/pc.c b/hw/i386/pc.c

> index 4e323755d0..416fb0e0f6 100644

> --- a/hw/i386/pc.c

> +++ b/hw/i386/pc.c

> @@ -1142,28 +1142,31 @@ void pc_basic_device_init(struct PCMachineState *pcms,

>       * 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())) {

> +    if (pcms->hpet_enabled && (!kvm_irqchip_in_kernel() ||

> +                               kvm_has_pit_state2())) {

>          hpet = qdev_try_new(TYPE_HPET);

> -        if (hpet) {

> -            /* For pc-piix-*, hpet's intcap is always IRQ2. For pc-q35-1.7

> -             * and earlier, use IRQ2 for compat. Otherwise, use IRQ16~23,

> -             * IRQ8 and IRQ2.

> -             */

> -            uint8_t compat = object_property_get_uint(OBJECT(hpet),

> -                    HPET_INTCAP, NULL);

> -            if (!compat) {

> -                qdev_prop_set_uint32(hpet, HPET_INTCAP, hpet_irqs);

> -            }

> -            sysbus_realize_and_unref(SYS_BUS_DEVICE(hpet), &error_fatal);

> -            sysbus_mmio_map(SYS_BUS_DEVICE(hpet), 0, HPET_BASE);

> +        if (!hpet) {

> +            error_report("couldn't create HPET device");

> +            exit(1);

> +        }

> +        /* For pc-piix-*, hpet's intcap is always IRQ2. For pc-q35-1.7

> +            * and earlier, use IRQ2 for compat. Otherwise, use IRQ16~23,

> +            * IRQ8 and IRQ2.

> +            */

> +        uint8_t compat = object_property_get_uint(OBJECT(hpet),

> +                HPET_INTCAP, NULL);

> +        if (!compat) {

> +            qdev_prop_set_uint32(hpet, HPET_INTCAP, hpet_irqs);

> +        }

> +        sysbus_realize_and_unref(SYS_BUS_DEVICE(hpet), &error_fatal);

> +        sysbus_mmio_map(SYS_BUS_DEVICE(hpet), 0, HPET_BASE);

>  

> -            for (i = 0; i < GSI_NUM_PINS; i++) {

> -                sysbus_connect_irq(SYS_BUS_DEVICE(hpet), i, gsi[i]);

> -            }

> -            pit_isa_irq = -1;

> -            pit_alt_irq = qdev_get_gpio_in(hpet, HPET_LEGACY_PIT_INT);

> -            rtc_irq = qdev_get_gpio_in(hpet, HPET_LEGACY_RTC_INT);

> +        for (i = 0; i < GSI_NUM_PINS; i++) {

> +            sysbus_connect_irq(SYS_BUS_DEVICE(hpet), i, gsi[i]);

>          }

> +        pit_isa_irq = -1;

> +        pit_alt_irq = qdev_get_gpio_in(hpet, HPET_LEGACY_PIT_INT);

> +        rtc_irq = qdev_get_gpio_in(hpet, HPET_LEGACY_RTC_INT);

>      }

>      *rtc_state = mc146818_rtc_init(isa_bus, 2000, rtc_irq);

>  

> @@ -1535,6 +1538,20 @@ static void pc_machine_set_pit(Object *obj, bool value, Error **errp)

>      pcms->pit_enabled = value;

>  }

>  

> +static bool pc_machine_get_hpet(Object *obj, Error **errp)

> +{

> +    PCMachineState *pcms = PC_MACHINE(obj);

> +

> +    return pcms->hpet_enabled;

> +}

> +

> +static void pc_machine_set_hpet(Object *obj, bool value, Error **errp)

> +{

> +    PCMachineState *pcms = PC_MACHINE(obj);

> +

> +    pcms->hpet_enabled = value;

> +}

> +

>  static void pc_machine_get_max_ram_below_4g(Object *obj, Visitor *v,

>                                              const char *name, void *opaque,

>                                              Error **errp)

> @@ -1585,6 +1602,9 @@ static void pc_machine_initfn(Object *obj)

>      pcms->smbus_enabled = true;

>      pcms->sata_enabled = true;

>      pcms->pit_enabled = true;

> +#ifdef CONFIG_HPET

> +    pcms->hpet_enabled = true;

> +#endif

>  

>      pc_system_flash_create(pcms);

>      pcms->pcspk = isa_new(TYPE_PC_SPEAKER);

> @@ -1705,6 +1725,9 @@ static void pc_machine_class_init(ObjectClass *oc, void *data)

>  

>      object_class_property_add_bool(oc, PC_MACHINE_PIT,

>          pc_machine_get_pit, pc_machine_set_pit);

> +

> +    object_class_property_add_bool(oc, "hpet",

> +        pc_machine_get_hpet, pc_machine_set_hpet);

>  }

>  

>  static const TypeInfo pc_machine_info = {

> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c

> index 0cf22a57ad..13d1628f13 100644

> --- a/hw/i386/pc_piix.c

> +++ b/hw/i386/pc_piix.c

> @@ -216,7 +216,7 @@ static void pc_init1(MachineState *machine,

>          i440fx_state = NULL;

>          isa_bus = isa_bus_new(NULL, get_system_memory(), system_io,

>                                &error_abort);

> -        no_hpet = 1;

> +        pcms->hpet_enabled = false;

>      }

>      isa_bus_irqs(isa_bus, x86ms->gsi);

>  

> diff --git a/softmmu/vl.c b/softmmu/vl.c

> index cb476aa70b..c2281f45a8 100644

> --- a/softmmu/vl.c

> +++ b/softmmu/vl.c

> @@ -146,7 +146,6 @@ static Chardev **serial_hds;

>  Chardev *parallel_hds[MAX_PARALLEL_PORTS];

>  int win2k_install_hack = 0;

>  int singlestep = 0;

> -int no_hpet = 0;

>  int fd_bootchk = 1;

>  static int no_reboot;

>  int no_shutdown = 0;

> @@ -3562,7 +3561,8 @@ void qemu_init(int argc, char **argv, char **envp)

>                  qemu_opts_parse_noisily(olist, "acpi=off", false);

>                  break;

>              case QEMU_OPTION_no_hpet:

> -                no_hpet = 1;

> +                olist = qemu_find_opts("machine");

> +                qemu_opts_parse_noisily(olist, "hpet=off", false);

>                  break;

>              case QEMU_OPTION_no_reboot:

>                  no_reboot = 1;

> 


Acked-by: Paolo Bonzini <pbonzini@redhat.com>


Thanks!

Paolo
Michael S. Tsirkin Oct. 22, 2020, 11:40 a.m. UTC | #2
On Wed, Oct 21, 2020 at 05:28:24PM +0200, Paolo Bonzini wrote:
> On 21/10/20 16:47, Eduardo Habkost wrote:

> > Get rid of yet another global variable.

> > 

> > The default will be hpet=on only if CONFIG_HPET=y.

> > 

> > Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

> > ---

> > Changes v2 -> v3:

> > * Revert v2 changes (use "hpet" property), plus:

> > * Default to hpet=off if CONFIG_HPET=n

> > * Error out if creation of HPET device fails and hpet=on

> > 

> > Changes v1 -> v2:

> > * Rename property to "allow-hpet" to make its semantic clearer,

> >   as it won't make sure HPET is created if CONFIG_HPET=n

> > * Use qdev_new(TYPE_HPET) at pc_basic_device_init()

> > ---

> >  include/hw/i386/pc.h  |  1 +

> >  include/hw/i386/x86.h |  3 ---

> >  hw/i386/pc.c          | 61 +++++++++++++++++++++++++++++--------------

> >  hw/i386/pc_piix.c     |  2 +-

> >  softmmu/vl.c          |  4 +--

> >  5 files changed, 46 insertions(+), 25 deletions(-)

> > 

> > diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h

> > index 84639d0ebc..911e460097 100644

> > --- a/include/hw/i386/pc.h

> > +++ b/include/hw/i386/pc.h

> > @@ -43,6 +43,7 @@ typedef struct PCMachineState {

> >      bool smbus_enabled;

> >      bool sata_enabled;

> >      bool pit_enabled;

> > +    bool hpet_enabled;

> >  

> >      /* NUMA information: */

> >      uint64_t numa_nodes;

> > diff --git a/include/hw/i386/x86.h b/include/hw/i386/x86.h

> > index d5dcf7a07f..4e66a15ff5 100644

> > --- a/include/hw/i386/x86.h

> > +++ b/include/hw/i386/x86.h

> > @@ -124,7 +124,4 @@ qemu_irq x86_allocate_cpu_irq(void);

> >  void gsi_handler(void *opaque, int n, int level);

> >  void ioapic_init_gsi(GSIState *gsi_state, const char *parent_name);

> >  

> > -/* hpet.c */

> > -extern int no_hpet;

> > -

> >  #endif

> > diff --git a/hw/i386/pc.c b/hw/i386/pc.c

> > index 4e323755d0..416fb0e0f6 100644

> > --- a/hw/i386/pc.c

> > +++ b/hw/i386/pc.c

> > @@ -1142,28 +1142,31 @@ void pc_basic_device_init(struct PCMachineState *pcms,

> >       * 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())) {

> > +    if (pcms->hpet_enabled && (!kvm_irqchip_in_kernel() ||

> > +                               kvm_has_pit_state2())) {

> >          hpet = qdev_try_new(TYPE_HPET);

> > -        if (hpet) {

> > -            /* For pc-piix-*, hpet's intcap is always IRQ2. For pc-q35-1.7

> > -             * and earlier, use IRQ2 for compat. Otherwise, use IRQ16~23,

> > -             * IRQ8 and IRQ2.

> > -             */

> > -            uint8_t compat = object_property_get_uint(OBJECT(hpet),

> > -                    HPET_INTCAP, NULL);

> > -            if (!compat) {

> > -                qdev_prop_set_uint32(hpet, HPET_INTCAP, hpet_irqs);

> > -            }

> > -            sysbus_realize_and_unref(SYS_BUS_DEVICE(hpet), &error_fatal);

> > -            sysbus_mmio_map(SYS_BUS_DEVICE(hpet), 0, HPET_BASE);

> > +        if (!hpet) {

> > +            error_report("couldn't create HPET device");

> > +            exit(1);

> > +        }

> > +        /* For pc-piix-*, hpet's intcap is always IRQ2. For pc-q35-1.7

> > +            * and earlier, use IRQ2 for compat. Otherwise, use IRQ16~23,

> > +            * IRQ8 and IRQ2.

> > +            */

> > +        uint8_t compat = object_property_get_uint(OBJECT(hpet),

> > +                HPET_INTCAP, NULL);

> > +        if (!compat) {

> > +            qdev_prop_set_uint32(hpet, HPET_INTCAP, hpet_irqs);

> > +        }

> > +        sysbus_realize_and_unref(SYS_BUS_DEVICE(hpet), &error_fatal);

> > +        sysbus_mmio_map(SYS_BUS_DEVICE(hpet), 0, HPET_BASE);

> >  

> > -            for (i = 0; i < GSI_NUM_PINS; i++) {

> > -                sysbus_connect_irq(SYS_BUS_DEVICE(hpet), i, gsi[i]);

> > -            }

> > -            pit_isa_irq = -1;

> > -            pit_alt_irq = qdev_get_gpio_in(hpet, HPET_LEGACY_PIT_INT);

> > -            rtc_irq = qdev_get_gpio_in(hpet, HPET_LEGACY_RTC_INT);

> > +        for (i = 0; i < GSI_NUM_PINS; i++) {

> > +            sysbus_connect_irq(SYS_BUS_DEVICE(hpet), i, gsi[i]);

> >          }

> > +        pit_isa_irq = -1;

> > +        pit_alt_irq = qdev_get_gpio_in(hpet, HPET_LEGACY_PIT_INT);

> > +        rtc_irq = qdev_get_gpio_in(hpet, HPET_LEGACY_RTC_INT);

> >      }

> >      *rtc_state = mc146818_rtc_init(isa_bus, 2000, rtc_irq);

> >  

> > @@ -1535,6 +1538,20 @@ static void pc_machine_set_pit(Object *obj, bool value, Error **errp)

> >      pcms->pit_enabled = value;

> >  }

> >  

> > +static bool pc_machine_get_hpet(Object *obj, Error **errp)

> > +{

> > +    PCMachineState *pcms = PC_MACHINE(obj);

> > +

> > +    return pcms->hpet_enabled;

> > +}

> > +

> > +static void pc_machine_set_hpet(Object *obj, bool value, Error **errp)

> > +{

> > +    PCMachineState *pcms = PC_MACHINE(obj);

> > +

> > +    pcms->hpet_enabled = value;

> > +}

> > +

> >  static void pc_machine_get_max_ram_below_4g(Object *obj, Visitor *v,

> >                                              const char *name, void *opaque,

> >                                              Error **errp)

> > @@ -1585,6 +1602,9 @@ static void pc_machine_initfn(Object *obj)

> >      pcms->smbus_enabled = true;

> >      pcms->sata_enabled = true;

> >      pcms->pit_enabled = true;

> > +#ifdef CONFIG_HPET

> > +    pcms->hpet_enabled = true;

> > +#endif

> >  

> >      pc_system_flash_create(pcms);

> >      pcms->pcspk = isa_new(TYPE_PC_SPEAKER);

> > @@ -1705,6 +1725,9 @@ static void pc_machine_class_init(ObjectClass *oc, void *data)

> >  

> >      object_class_property_add_bool(oc, PC_MACHINE_PIT,

> >          pc_machine_get_pit, pc_machine_set_pit);

> > +

> > +    object_class_property_add_bool(oc, "hpet",

> > +        pc_machine_get_hpet, pc_machine_set_hpet);

> >  }

> >  

> >  static const TypeInfo pc_machine_info = {

> > diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c

> > index 0cf22a57ad..13d1628f13 100644

> > --- a/hw/i386/pc_piix.c

> > +++ b/hw/i386/pc_piix.c

> > @@ -216,7 +216,7 @@ static void pc_init1(MachineState *machine,

> >          i440fx_state = NULL;

> >          isa_bus = isa_bus_new(NULL, get_system_memory(), system_io,

> >                                &error_abort);

> > -        no_hpet = 1;

> > +        pcms->hpet_enabled = false;

> >      }

> >      isa_bus_irqs(isa_bus, x86ms->gsi);

> >  

> > diff --git a/softmmu/vl.c b/softmmu/vl.c

> > index cb476aa70b..c2281f45a8 100644

> > --- a/softmmu/vl.c

> > +++ b/softmmu/vl.c

> > @@ -146,7 +146,6 @@ static Chardev **serial_hds;

> >  Chardev *parallel_hds[MAX_PARALLEL_PORTS];

> >  int win2k_install_hack = 0;

> >  int singlestep = 0;

> > -int no_hpet = 0;

> >  int fd_bootchk = 1;

> >  static int no_reboot;

> >  int no_shutdown = 0;

> > @@ -3562,7 +3561,8 @@ void qemu_init(int argc, char **argv, char **envp)

> >                  qemu_opts_parse_noisily(olist, "acpi=off", false);

> >                  break;

> >              case QEMU_OPTION_no_hpet:

> > -                no_hpet = 1;

> > +                olist = qemu_find_opts("machine");

> > +                qemu_opts_parse_noisily(olist, "hpet=off", false);

> >                  break;

> >              case QEMU_OPTION_no_reboot:

> >                  no_reboot = 1;

> > 

> 

> Acked-by: Paolo Bonzini <pbonzini@redhat.com>

> 

> Thanks!

> 

> Paolo


Reviewed-by: Michael S. Tsirkin <mst@redhat.com>


I will queue this, thanks!
diff mbox series

Patch

diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 84639d0ebc..911e460097 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -43,6 +43,7 @@  typedef struct PCMachineState {
     bool smbus_enabled;
     bool sata_enabled;
     bool pit_enabled;
+    bool hpet_enabled;
 
     /* NUMA information: */
     uint64_t numa_nodes;
diff --git a/include/hw/i386/x86.h b/include/hw/i386/x86.h
index d5dcf7a07f..4e66a15ff5 100644
--- a/include/hw/i386/x86.h
+++ b/include/hw/i386/x86.h
@@ -124,7 +124,4 @@  qemu_irq x86_allocate_cpu_irq(void);
 void gsi_handler(void *opaque, int n, int level);
 void ioapic_init_gsi(GSIState *gsi_state, const char *parent_name);
 
-/* hpet.c */
-extern int no_hpet;
-
 #endif
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 4e323755d0..416fb0e0f6 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1142,28 +1142,31 @@  void pc_basic_device_init(struct PCMachineState *pcms,
      * 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())) {
+    if (pcms->hpet_enabled && (!kvm_irqchip_in_kernel() ||
+                               kvm_has_pit_state2())) {
         hpet = qdev_try_new(TYPE_HPET);
-        if (hpet) {
-            /* For pc-piix-*, hpet's intcap is always IRQ2. For pc-q35-1.7
-             * and earlier, use IRQ2 for compat. Otherwise, use IRQ16~23,
-             * IRQ8 and IRQ2.
-             */
-            uint8_t compat = object_property_get_uint(OBJECT(hpet),
-                    HPET_INTCAP, NULL);
-            if (!compat) {
-                qdev_prop_set_uint32(hpet, HPET_INTCAP, hpet_irqs);
-            }
-            sysbus_realize_and_unref(SYS_BUS_DEVICE(hpet), &error_fatal);
-            sysbus_mmio_map(SYS_BUS_DEVICE(hpet), 0, HPET_BASE);
+        if (!hpet) {
+            error_report("couldn't create HPET device");
+            exit(1);
+        }
+        /* For pc-piix-*, hpet's intcap is always IRQ2. For pc-q35-1.7
+            * and earlier, use IRQ2 for compat. Otherwise, use IRQ16~23,
+            * IRQ8 and IRQ2.
+            */
+        uint8_t compat = object_property_get_uint(OBJECT(hpet),
+                HPET_INTCAP, NULL);
+        if (!compat) {
+            qdev_prop_set_uint32(hpet, HPET_INTCAP, hpet_irqs);
+        }
+        sysbus_realize_and_unref(SYS_BUS_DEVICE(hpet), &error_fatal);
+        sysbus_mmio_map(SYS_BUS_DEVICE(hpet), 0, HPET_BASE);
 
-            for (i = 0; i < GSI_NUM_PINS; i++) {
-                sysbus_connect_irq(SYS_BUS_DEVICE(hpet), i, gsi[i]);
-            }
-            pit_isa_irq = -1;
-            pit_alt_irq = qdev_get_gpio_in(hpet, HPET_LEGACY_PIT_INT);
-            rtc_irq = qdev_get_gpio_in(hpet, HPET_LEGACY_RTC_INT);
+        for (i = 0; i < GSI_NUM_PINS; i++) {
+            sysbus_connect_irq(SYS_BUS_DEVICE(hpet), i, gsi[i]);
         }
+        pit_isa_irq = -1;
+        pit_alt_irq = qdev_get_gpio_in(hpet, HPET_LEGACY_PIT_INT);
+        rtc_irq = qdev_get_gpio_in(hpet, HPET_LEGACY_RTC_INT);
     }
     *rtc_state = mc146818_rtc_init(isa_bus, 2000, rtc_irq);
 
@@ -1535,6 +1538,20 @@  static void pc_machine_set_pit(Object *obj, bool value, Error **errp)
     pcms->pit_enabled = value;
 }
 
+static bool pc_machine_get_hpet(Object *obj, Error **errp)
+{
+    PCMachineState *pcms = PC_MACHINE(obj);
+
+    return pcms->hpet_enabled;
+}
+
+static void pc_machine_set_hpet(Object *obj, bool value, Error **errp)
+{
+    PCMachineState *pcms = PC_MACHINE(obj);
+
+    pcms->hpet_enabled = value;
+}
+
 static void pc_machine_get_max_ram_below_4g(Object *obj, Visitor *v,
                                             const char *name, void *opaque,
                                             Error **errp)
@@ -1585,6 +1602,9 @@  static void pc_machine_initfn(Object *obj)
     pcms->smbus_enabled = true;
     pcms->sata_enabled = true;
     pcms->pit_enabled = true;
+#ifdef CONFIG_HPET
+    pcms->hpet_enabled = true;
+#endif
 
     pc_system_flash_create(pcms);
     pcms->pcspk = isa_new(TYPE_PC_SPEAKER);
@@ -1705,6 +1725,9 @@  static void pc_machine_class_init(ObjectClass *oc, void *data)
 
     object_class_property_add_bool(oc, PC_MACHINE_PIT,
         pc_machine_get_pit, pc_machine_set_pit);
+
+    object_class_property_add_bool(oc, "hpet",
+        pc_machine_get_hpet, pc_machine_set_hpet);
 }
 
 static const TypeInfo pc_machine_info = {
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 0cf22a57ad..13d1628f13 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -216,7 +216,7 @@  static void pc_init1(MachineState *machine,
         i440fx_state = NULL;
         isa_bus = isa_bus_new(NULL, get_system_memory(), system_io,
                               &error_abort);
-        no_hpet = 1;
+        pcms->hpet_enabled = false;
     }
     isa_bus_irqs(isa_bus, x86ms->gsi);
 
diff --git a/softmmu/vl.c b/softmmu/vl.c
index cb476aa70b..c2281f45a8 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -146,7 +146,6 @@  static Chardev **serial_hds;
 Chardev *parallel_hds[MAX_PARALLEL_PORTS];
 int win2k_install_hack = 0;
 int singlestep = 0;
-int no_hpet = 0;
 int fd_bootchk = 1;
 static int no_reboot;
 int no_shutdown = 0;
@@ -3562,7 +3561,8 @@  void qemu_init(int argc, char **argv, char **envp)
                 qemu_opts_parse_noisily(olist, "acpi=off", false);
                 break;
             case QEMU_OPTION_no_hpet:
-                no_hpet = 1;
+                olist = qemu_find_opts("machine");
+                qemu_opts_parse_noisily(olist, "hpet=off", false);
                 break;
             case QEMU_OPTION_no_reboot:
                 no_reboot = 1;