Patchwork [1/4] xen: introduce mc146818rtcxen

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Submitter Stefano Stabellini
Date Nov. 15, 2011, 2:51 p.m.
Message ID <1321368671-1134-1-git-send-email-stefano.stabellini@eu.citrix.com>
Download mbox | patch
Permalink /patch/125796/
State New
Headers show

Comments

Stefano Stabellini - Nov. 15, 2011, 2:51 p.m.
From: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

Xen doesn't need full RTC emulation in Qemu because the RTC is already
emulated by the hypervisor. In particular we want to avoid the timers
initialization so that Qemu doesn't need to wake up needlessly.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
 hw/mc146818rtc.c |   36 +++++++++++++++++++++++++++++++++++-
 1 files changed, 35 insertions(+), 1 deletions(-)
Anthony Liguori - Nov. 15, 2011, 2:54 p.m.
On 11/15/2011 08:51 AM, stefano.stabellini@eu.citrix.com wrote:
> From: Stefano Stabellini<stefano.stabellini@eu.citrix.com>
>
> Xen doesn't need full RTC emulation in Qemu because the RTC is already
> emulated by the hypervisor. In particular we want to avoid the timers
> initialization so that Qemu doesn't need to wake up needlessly.
>
> Signed-off-by: Stefano Stabellini<stefano.stabellini@eu.citrix.com>

Yuck.  There's got to be a better way to do this.

I think it would be better to name timers and then in Xen specific machine code, 
disable the RTC timers.

Regards,

Anthony Liguori

> ---
>   hw/mc146818rtc.c |   36 +++++++++++++++++++++++++++++++++++-
>   1 files changed, 35 insertions(+), 1 deletions(-)
>
> diff --git a/hw/mc146818rtc.c b/hw/mc146818rtc.c
> index 2aaca2f..91242d0 100644
> --- a/hw/mc146818rtc.c
> +++ b/hw/mc146818rtc.c
> @@ -28,6 +28,7 @@
>   #include "apic.h"
>   #include "isa.h"
>   #include "mc146818rtc.h"
> +#include "arch_init.h"
>
>   //#define DEBUG_CMOS
>   //#define DEBUG_COALESCED
> @@ -614,6 +615,17 @@ static const MemoryRegionOps cmos_ops = {
>       .old_portio = cmos_portio
>   };
>
> +static int rtcxen_initfn(ISADevice *dev)
> +{
> +    int base = 0x70;
> +    RTCState *s = DO_UPCAST(RTCState, dev, dev);
> +
> +    memory_region_init_io(&s->io,&cmos_ops, s, "rtc", 2);
> +    isa_register_ioport(dev,&s->io, base);
> +
> +    return 0;
> +}
> +
>   static int rtc_initfn(ISADevice *dev)
>   {
>       RTCState *s = DO_UPCAST(RTCState, dev, dev);
> @@ -655,7 +667,11 @@ ISADevice *rtc_init(int base_year, qemu_irq intercept_irq)
>       ISADevice *dev;
>       RTCState *s;
>
> -    dev = isa_create("mc146818rtc");
> +    if (xen_available()) {
> +        dev = isa_create("mc146818rtcxen");
> +    } else {
> +        dev = isa_create("mc146818rtc");
> +    }
>       s = DO_UPCAST(RTCState, dev, dev);
>       qdev_prop_set_int32(&dev->qdev, "base_year", base_year);
>       qdev_init_nofail(&dev->qdev);
> @@ -684,3 +700,21 @@ static void mc146818rtc_register(void)
>       isa_qdev_register(&mc146818rtc_info);
>   }
>   device_init(mc146818rtc_register)
> +
> +static ISADeviceInfo mc146818rtcxen_info = {
> +    .qdev.name     = "mc146818rtcxen",
> +    .qdev.size     = sizeof(RTCState),
> +    .qdev.no_user  = 1,
> +    .qdev.vmsd     =&vmstate_rtc,
> +    .init          = rtcxen_initfn,
> +    .qdev.props    = (Property[]) {
> +        DEFINE_PROP_INT32("base_year", RTCState, base_year, 1980),
> +        DEFINE_PROP_END_OF_LIST(),
> +    }
> +};
> +
> +static void mc146818rtcxen_register(void)
> +{
> +    isa_qdev_register(&mc146818rtcxen_info);
> +}
> +device_init(mc146818rtcxen_register)

Patch

diff --git a/hw/mc146818rtc.c b/hw/mc146818rtc.c
index 2aaca2f..91242d0 100644
--- a/hw/mc146818rtc.c
+++ b/hw/mc146818rtc.c
@@ -28,6 +28,7 @@ 
 #include "apic.h"
 #include "isa.h"
 #include "mc146818rtc.h"
+#include "arch_init.h"
 
 //#define DEBUG_CMOS
 //#define DEBUG_COALESCED
@@ -614,6 +615,17 @@  static const MemoryRegionOps cmos_ops = {
     .old_portio = cmos_portio
 };
 
+static int rtcxen_initfn(ISADevice *dev)
+{
+    int base = 0x70;
+    RTCState *s = DO_UPCAST(RTCState, dev, dev);
+
+    memory_region_init_io(&s->io, &cmos_ops, s, "rtc", 2);
+    isa_register_ioport(dev, &s->io, base);
+
+    return 0;
+}
+
 static int rtc_initfn(ISADevice *dev)
 {
     RTCState *s = DO_UPCAST(RTCState, dev, dev);
@@ -655,7 +667,11 @@  ISADevice *rtc_init(int base_year, qemu_irq intercept_irq)
     ISADevice *dev;
     RTCState *s;
 
-    dev = isa_create("mc146818rtc");
+    if (xen_available()) {
+        dev = isa_create("mc146818rtcxen");
+    } else {
+        dev = isa_create("mc146818rtc");
+    }
     s = DO_UPCAST(RTCState, dev, dev);
     qdev_prop_set_int32(&dev->qdev, "base_year", base_year);
     qdev_init_nofail(&dev->qdev);
@@ -684,3 +700,21 @@  static void mc146818rtc_register(void)
     isa_qdev_register(&mc146818rtc_info);
 }
 device_init(mc146818rtc_register)
+
+static ISADeviceInfo mc146818rtcxen_info = {
+    .qdev.name     = "mc146818rtcxen",
+    .qdev.size     = sizeof(RTCState),
+    .qdev.no_user  = 1,
+    .qdev.vmsd     = &vmstate_rtc,
+    .init          = rtcxen_initfn,
+    .qdev.props    = (Property[]) {
+        DEFINE_PROP_INT32("base_year", RTCState, base_year, 1980),
+        DEFINE_PROP_END_OF_LIST(),
+    }
+};
+
+static void mc146818rtcxen_register(void)
+{
+    isa_qdev_register(&mc146818rtcxen_info);
+}
+device_init(mc146818rtcxen_register)